Can your genes predict the best weight loss diet for you?

The Study

It has been hypothesized that your genetic makeup can predict which weight loss strategy will be the most effective for you. In this interesting study, 609 adults were randomized to either a low-fat or low-carb diet for 12 months. Previous research has suggested that a certain genotype that impacts carbohydrate metabolism may help a person be more successful with a low-carb diet. Similarly, another genotype that influences fat metabolism has been identified that may make a person more successful on a low-fat diet. Before the trial began, subjects were tested for this low-fat or low-carb response gene sequence.  

Among the participants randomized to the low-fat diet, 130 had the low-fat gene and 83 had the low-carb gene. Among the participants randomized to the low-carb diet, 114 had the low-fat gene and 97 had the low-carb gene. By the end of the 12 month follow-up, there were no differences in weight lost between the two groups and neither the low-fat or low-carb genotype predicted weight loss success.

Journal of the American Medical Association 2018; 319:667.

Take Home Message

Although the idea that our genes can tell us what weight loss diet is best for us is intriguing, this study does not provide evidence that this is the case. More research is needed before we can definitively answer this question.

Dietary Insulin And Colon Cancer

The Study

In this investigation, Harvard researchers created a dietary scoring system of foods that promote a high insulin response. They called it the Empirical Dietary Index for Hyperinsulinemia (EDIH). This is different than the glycemic index, which focuses on the blood sugar effects of carbohydrate containing foods. This index includes all foods that spike insulin after consumption. 

The food groups that contributed to a high EDIH score include red meat, low energy soda, cream soups, processed meats, margarine, poultry, French fries, fish, sugar sweetened beverages, tomatoes, low fat dairy and eggs.

The food groups that contributed to a low EDIH score included wine, coffee, fruit, high fat dairy products and green leafy vegetables.

Over 120,000 men and women from the Nurses’ Health Study and the Health Professional Follow-up Study had an EDIH score calculated for their diet and were followed for 26 years. Subjects with the greatest EDIH score had a statistically significant 26% higher risk of colon cancer when compared to subjects with the lowest EDIH score. American Journal of Clinical Nutrition 2018; 108:363-70.

Take Home Message

When choosing a diet to promote weight loss, you always want to look at the long-term health effects of the diet as well.   

The EDIH score takes the idea of the glycemic index a step further. The GI focuses on the blood sugar effects of carbohydrate foods. The EDIH score includes any food that increases insulin. A lot of these foods are proteins. Many popular current diets are really high in animal protein, and this study makes you think twice about them. 

As far as mechanisms go, it is thought that very high levels of insulin, and insulin derived growth hormone may be carcinogenic. 

In addition to keeping your glycemic index low, it is a good idea to go easy on the animal proteins. It is particularly important to limit red meat and processed meats. It is also a good idea to substitute vegetable proteins such as beans, nuts, whole grains and legumes for animal proteins whenever possible.

Carbohydrate Consumption And Mortality

Carbohydrate consumption has been a hot button issue in the field of nutrition for decades. The type and amount of carbohydrate we should be including in our diets is the subject of intense debate in both the research and weight loss communities. This is a subject that is near and dear to my own heart since carbohydrate metabolism was the subject of my own doctoral research. A new study has been published on this topic that is well done and very important.

The Article

This investigation actually consists of two separate studies (Reference 1). The first is a prospective cohort study using the ARIC cohort (The Atherosclerosis Risk in Communities). The second is a meta-analysis including 7 separate studies.

Results

Prospective Cohort Study in the ARIC Cohort

Over 15,000 adults aged 45-64 years in 4 U.S. communities had their diet assessed by means of a food frequency questionnaire and were followed for 25 years. Subjects who consumed 50-55% of their calories as carbohydrate had the lowest mortality rate. Subjects who ate more or less carbohydrate had an increased mortality risk.

-A 50 year old subject consuming less than 30% of calories as carbohydrate would have a projected life expectancy of 29.1 years.

- A 50 year old subject consuming 50-55% of calories as carbohydrate would have a projected life expectancy of 33.1 years.

A 50 year old subject consuming greater than 65% of calories as carbohydrate would have a projected life expectancy of 32 years.

Meta-analysis

The meta-analysis consisted of 8 separate studies with a total of 432,179 subjects and showed a similar result. There was an increased risk of mortality with both a low and high carbohydrate intake when compared to a moderate carbohydrate intake.

Subjects consuming less than 40% of calories as carbohydrate had a statistically significant 20% higher risk of mortality.

Subjects consuming greater than 70% of calories as carbohydrate had a statistically significant 23% higher risk of mortality.

Substituting animal fat and protein for carbohydrate resulted in an increased risk of mortality.

Substituting vegetable fat and protein for carbohydrate resulted in a decreased risk of mortality.

Conclusions And Recommendations

Many people manipulate their carbohydrate consumption in an effort to lose weight. It is really important to examine what effect these weight loss diets may have on long term health. My professional goal has always been to provide a strategy that helps my client lose weight effectively, while improving overall health and decreasing risk of chronic disease. 

This study sheds some light on the long-term health effects of diets that severely manipulate carbohydrate consumption. The mechanisms are pretty straight forward. A low carb diet will generally include less healthy foods such as fruits, vegetables and whole grains and higher amounts of red meat and saturated fat. This results in fewer vitamins, minerals, fiber and cancer fighting phytochemicals. This eating pattern likely results in higher levels of oxidative stress, inflammation and biological aging.

On the other hand, diets very high in carbohydrates tend to include too many refined carbohydrates and not enough healthy vegetable fat. This results in a much higher dietary glycemic load, which has been associated with many negative health outcomes.

Here is what we learn from this important study:

1) Going very low carb is probably not a great idea.

2) Going very high carb is probably not a great idea.

3) Stay in the mid carb range, which is around 50-55% of calories.

4) The quality of carbohydrates consumed is of the utmost importance. Focus on low glycemic carbs such as fruits, vegetables, legumes and whole grains.

5) The majority of your fat should be vegetable fats such as nuts, avocado, nut butters, seeds and healthy vegetable oils such as olive oil and canola oil.

6) Minimize sources of protein that are high in saturated fat, especially red meat and processed meats like bacon, sausage, pepperoni, hot dogs, etc. 

References

1) Seidelmann SB, et al. Dietary carbohydrate intake and mortality; a prospective cohort study and meta-analysis. Lancet Public Health 2018; 9:pe419-e428.

Can I Eat Nuts If I Am Trying To Lose Weight?

Nuts absolutely fit into a weight loss diet.  Here are some of the great things about them:

-They are low glycemic load and therefore are very easy on the blood sugar.

-They contain a healthy source of protein.

-They contain fiber.

-They contain vitamins.

-They contain minerals.

-They contain very healthy sources of fat.

High nut consumption has been associated with a lower risk of heart disease and type 2 diabetes in Harvard prospective cohort studies (Reference 1 and 2).  Now nuts do contain a lot of calories, so you have to be a little careful with your portions.

However, an analysis in the Nurse Health Study showed that women who ate nuts more frequently actually had a reduced risk of obesity compared to women ate them less often (Reference 3).  Feel free to include nuts regularly in your diet, even if you are trying to lose weight.

References

1) Hu FB et al. Frequent nut consumption and risk of coronary heart disease in women: prospective cohort study. British Medical Journal 1998; 317:1341-45.

2) Jiang R, et al. Nut and peanut butter consumption and risk of type 2 diabetes. Journal of the American Medical Association 2002; 288:2554-60.

3) Bes-Rastrollo M, et al. Prospective study of nut consumption, long term weight change and obesity risk in women. American Journal of Clinical Nutrition 2009; 89:1913-19.

Is Sugar Addiction Genetic?

The Study

In the last few years, evidence suggests that sugar is addictive, similar to alcohol or tobacco. A recent publication tested the hypothesis that sugar addiction is genetic. In this investigation, 108 healthy weight adolescents were given milkshakes with varying sugar contents while undergoing a functional brain MRI. If both parents were overweight, the subject was considered at high risk of becoming overweight. If neither or just one parent was overweight, the subject was considered to be at low risk.

Fifty-three of the subjects were considered high risk and fifty-five were considered low risk. When compared to the low risk subjects, the high risk adolescents showed a significantly greater striatal, gustatory and somatosensory response to the high sugar milk shake. These areas of the brain have been shown to be associated with reward and addiction. American Journal of Clinical Nutrition 2018; 107:859.

Take Home Message

This study tells us several things:

1) Sugar consumption appears to fire up the regions of the brain associated with reward and addiction. The research that this may be the case has been building for some time.

2) The authors conclude that sugar may be more responsible for habitual overeating than other dietary components, such as dietary fat. I agree with them.

3) There may be a genetic component to sugar addiction.

I have observed the addictive nature of sugar for years. In most people that I have worked with, if they have a little sugar, they want more and more. The best bet is to just swear off sugar entirely. Although this is really hard at first, after a few weeks, you’ll hardly miss it.  For most of us, limiting sugar to just a few servings a week is like telling an alcoholic to just have a few drinks per week. It simply doesn’t work. 

Carbohydrate Quality And Osteoporosis

The Study

Osteoporosis is a disease that reduces bone strength and markedly increases risk of fracture. It can dramatically reduce quality of life and ability to function as we age. In this study, 870 subjects from the Spanish based PREDIMED cohort had their glycemic index and glycemic load measured by food frequency questionnaire annually for 9 years. When compared to subjects with the lowest glycemic index, subjects with the highest glycemic index had an 80% higher risk of osteoporotic fracture. When compared to subjects with the lowest glycemic load, subjects with the highest glycemic load had a 320% higher risk of osteoporotic fracture. American Journal of Clinical Nutrition 2018; 107:1035.

Take Home Message

We can add osteoporosis to the growing list of diseases that may occur when we focus on the wrong carbohydrates. The authors believed that the increased blood sugars associated with high glycemic carbs explained the higher risk of osteoporosis through several potential mechanisms:

-Increased inflammation.

-Increased oxidative stress.

-A decrease in osteoblast activity.

-Acidosis.

-Inhibition of genes involved in osteoblast differentiation.

-An increased excretion of calcium in the urine.

To reduce the glycemic index and glycemic load of your diet, strictly limit refined carbohydrates such as bread, pasta, white rice and sugar. Focus on fruits, vegetables, legumes and whole grains such as oatmeal, brown rice and quinoa. You also don’t want to go too heavy on the carbs. Shoot for about 45-50% of your daily calories as carbohydrate.

Lifestyle Factors And Life Expectancy

A new study was recently published that is so compelling that it deserves its very own feature article. The study is titled “Impact of healthy lifestyle factors on life expectancies in the US population” and it was published in the journal Circulation. The authors of this investigation are the very best of the Harvard School of Public Health’s Department of Nutrition faculty, which includes Dr. Walter Willett, Dr. Frank Hu and Dr. Meir Stampfer (Reference 1).

Most nutrition research focuses on a very specific aspect of lifestyle and its impact on health. For example, “eating red meat increases incidence of colon cancer” or “eating oatmeal decreases serum cholesterol”. What makes this study so interesting is that several lifestyle behaviors are combined so we can see their cumulative impact on health.

The Article

This investigation used subjects from both The Nurses’ Health Study and The Health Professional Follow-up Study for a total of 123,219 men and women. The researchers created 5 lifestyle factors and scored each subject on how well they followed the behavior. Here is the scoring system:

1) Smoking: If the subject never smoked they received a score of 1. If they were a current smoker or had smoked in the past, they received a score of 0.

2) Physical Activity: If the subject engaged in 30 minutes or more of moderate to vigorous physical activity each day they received a score of 1. If they did less than this, they received a score of 0.

3) Alcohol Consumption: Low risk was considered an alcohol consumption of 5 to 15 grams per day for women (which equals 2.5-7.5 drinks per week) and 5 to 30 grams per day for men (which equals 2.5-14 drinks per week). If the subject’s alcohol consumption was in this range, they received a score of 1, if not they received a score of 0.

4) Body Mass Index: Low risk was considered a BMI between 18.5-24.9. If the subject’s BMI was in this range, they received a score of 1, if not they received a score of 0.

5) Diet: Subjects received a score of 1 for this variable if their diet was in the top 40% of the cohort distribution for the Alternate Healthy Eating Index. This diet score is based on a high consumption of vegetables, fruits, nuts, whole grains, polyunsaturated fats and long chain omega 3 fatty acids and a low intake of red and processed meats, sugar sweetened beverages, trans fat and sodium.

Each subject was given a score for the 5 lifestyle factors. A perfect lifestyle would be a score of “5”, while adhering to none of the lifestyle factors would yield a score of “0”.  Subjects were followed for up to 34 years.

Results

When comparing subjects who followed all 5 factors to subjects following none:

-Risk of all-cause mortality was 74% lower in subjects that followed all 5 factors.

-Risk of death from cancer was 65% lower in subjects that followed all 5 factors.

-Risk of death from cardiovascular disease was 82% lower in subjects that followed all 5 factors.

Starting at age 50, women following all 5 factors could expect to live another 43.1 years, while women following none of the factors could expect to live another 29 years.

Starting at age 50, men following all 5 factors could expect to live another 37.6 years, while men following none of the factors could expect to live another 25.5 years

The researchers ran an additional analysis with a stricter criterion for the lifestyle score.

Body mass index: A score of 1 was given to those with a BMI between 18.5 and 22.9.

Physical Activity: A score of 1 was given to those exercising more than 52 minutes per day.

Diet: A score of 5 was given to those in the top 20% of the distribution for the Alternate Healthy Eating Index.

The scoring for smoking and alcohol consumption were kept the same.

Women who followed this expanded score lived 20.5 years longer than those that followed none of the lifestyle factors. For men, the number was 19.6 years.

Conclusions And Recommendations

These results are truly remarkable. To think that by living a healthy lifestyle you could add up to 20 years to your life is amazing. The coolest part is that this study does not take into account quality of life, which is much higher if you follow these habits. If you are able to hit all 5 of these behaviors consistently, you will notice significant and positive changes in your energy, mood, immune system, confidence, mental focus/performance and how you handle stress. 

The take home message on this is one is simple. Go through each of the 5 lifestyle factors and give yourself a score. If you are at 5, you are all set and keep up the good work. If you are hitting less than 5, do your best to work towards a perfect score. Will it be easy to attain all 5 of these? Probably not. However, the effort you put into a healthy lifestyle is paid back to you many times over. It all begins with making your health a priority.

References

1) Li Y, et al. Impact of healthy lifestyle factors on life expectancies in the U.S. population Circulation 2018 DOI: 10.1161/CIRCULATIONAHA.117.032047.

Non-nutritive Sweeteners And Satiety

The Study

The GI system is believed to contain sweet taste receptors that have an important impact on satiety and hunger. In this interesting study, 12 healthy young men and women had each of the following preloads injected directly into their stomach on separate occasions: 1) 50 grams of glucose 2) 25 grams of fructose 3) 220 mg acesulfame-K, which is a non-nutritive sweetener. Visual analogue scales were used to rate subjective feelings of hunger and satiety. Compared to glucose and fructose, the non-nutritive sweetener initially caused a significantly stronger decrease in hunger and increase in satiety. However, this was followed by a significantly steeper return of hunger. American Journal of Clinical Nutrition 2018; 107:707.

Take Home Message

When I first started studying nutrition, the prevailing wisdom was that weight loss was all about calories in versus calories out. We now know that there is so much more to the story. A huge number of factors influence when and what we eat. Receptors in the GI system are now thought to play a big part. This is a fascinating study.  It utilizes my favorite study design, the crossover trial. In this type of study, each subject receives all interventions on separate occasions and acts as their own control. This really reduces the odds of residual confounding impacting the results. 

In this study, the artificial sweetener caused a significantly greater return to hunger when compared to the calorie containing sugars.  A diet soda or sugar-free dessert is a nice treat for those giving up sugar. However, it is a good idea to limit consumption of artificial sweeteners to just a few times per week. Daily use of non-nutritive sweeteners can have a dramatic effect on hunger and cravings for refined carbs. A few servings per week are not a problem, but daily consumption can really slow weight loss.

Sugar Consumption And Frailty

The Study

This study included 1,973 subjects from Spain over 60 years of age. Sugar consumption was measured with a computer based food frequency questionnaire. Frailty was defined as the presence of three of the following symptoms; exhaustion, low physical activity, slow gait speed, unintentional weight loss and muscle weakness. After several years of follow-up, subjects consuming the most sugar (greater than 36 grams or 9 teaspoons per day) had over twice the risk of frailty when compared to subjects consuming the least amount of sugar (less 15 grams or 4 teaspoons of sugar). American Journal of Clinical Nutrition 2018; 107:772.

Take Home Message

The research literature has shown that added sugar increases risk of obesity, type 2 diabetes, and heart disease. This study shows that it also may have a very negative impact on healthy aging. What makes this study interesting is that it focuses on quality of life and ability to function, rather than a single disease outcome. Do your very best to strictly limit sugar in your diet. Better yet, completely eliminate it.

Book Review: The Obesity Code

Next up for review is The Obesity Code: Unlocking The Secrets Of Weight Loss. The author, Dr. Jason Fung is a Canadian Nephrologist.

Introduction

This book theorizes that overeating and a sedentary lifestyle have little to do with the obesity epidemic. Dr. Fung believes that obesity is caused by high levels of insulin. The book includes sections on the origins of the obesity epidemic, why overeating and exercise are not that important, Dr. Fung’s new model of obesity, what is wrong with our diet and the solution, which details when to eat and what to eat. The book is 315 pages long and very well written. I enjoyed reading it.

5 Things I Really Liked About The Obesity Code

1) Dr. Fung uses a lot of research to back up his claims. While he does make a few errors in interpreting the nutrition literature, this is a refreshing change in comparison to most best-selling weight loss books.

2) I agree that insulin levels have a lot to do with weight gain. This is a major reason why I recommend a low glycemic load approach for weight loss with my own clients.

3) I totally agree with the restriction on snacking. Even small amounts of extra calories consumed daily can add up to significant weight gain over time. Three balanced meals a day are all we need.

4) I totally agree that added sugars and refined carbohydrates are major causes of weight gain for most of us. Eliminating them needs to be a big part of any weight loss strategy.

5) I like the section on the importance of sleep in weight loss. The research is really beginning to back this up. Short sleep appears to decrease leptin levels and increase ghrelin levels. Both hormones have a lot to do with your ability to lose weight.

5 Things I Didn’t Agree With in The Obesity Code

1) I do not understand Dr. Fung’s theories on exercise. Here is an example:

Page 50: “Physical activity has virtually no relationship to the prevalence of obesity.”

Many studies show that physical activity is a big part of the strategy for those that are successful losing weight. A white paper on my website summarizes a number of these studies (you can find it here).

Page 51: “Exercise has not decreased since hunter gatherer times.” Does Dr. Fung really believe that a sedentary office worker that drives to work and sits in front of a computer all day gets as much physical activity as a caveman who had to walk everywhere he went and hunt and forage for every calorie he ingested?

Page 54: “Exercise has many benefits, but weight loss is not among them”. Strangely, right after this quotation, Dr. Fung cites a randomized trial showing that subjects who exercised 5 times per week lost an extra 10 pounds over 10 months when compared to those that did not exercise.

Generally, exercise by itself is not enough to hit your weight loss goals, but in combination with dietary change, exercise plays a critical role.

2) Similar to his view on cardio, this book makes absolutely no mention of the importance of resistance training. Lifting weights decreases the loss of lean body mass as we lose weight. This makes it much more likely that weight we lose will stay off. Building muscle with weight training increases metabolism since muscle burns three times as many calories as fat. Burning more calories per day makes it much easier to lose weight over the long-term.

3) Dr. Fung believes that saturated fat is harmless. He recommends a regular consumption of butter, coconut oil, full fat dairy and beef tallow. He cites a reference from the Nurses’ Health Study to show that total fat is not associated with risk of heart disease (New England Journal of Medicine, 1997; 337:1491). While this is accurate, the rest of this study shows that the type of fat is very important. Saturated fat increased risk of heart disease in this cohort, while mono- and polyunsaturated fat decreased risk. Ironically, after citing this study, Dr. Fung says that saturated fat is fine and that vegetable oils have a negative impact on health. I am not quite sure how he mixed this up. Either way, saturated fat is to be avoided, it increases risk of heart disease.

4) I didn’t agree with the alcohol recommendations in The Obesity Code. Dr. Fung says up to 2 drinks a day are fine. It is my opinion that 14 drinks a week will seriously impede weight loss in both men and women. I have my clients cut down quite a bit on the alcohol if they are trying to lose weight.

5) This book recommends fasting 24 to 36 hours, two to three times per week. I don’t think this is a good idea. In the last year or so, I have blogged on 3 separate studies that examined fasting and were published in top journals. The results were not favorable. Among the findings:

-Drop out rates were higher in those fasting compared to more modest calorie restriction. This means it is much harder to stick to a fasting weight loss plan.

-There was no difference in weight loss between those fasting and those moderately restricting calories.

-LDL cholesterol significantly increased in subjects fasting.

-Several studies showed glucose dysregulation when fasting.

-Subjects fasting had an increase in inflammation.

-Subjects ate significantly more calories than normal the day after fasting.

-Energy expenditure decreased when fasting. 

(You can find these studies, here, here and here.) 

In The Obesity Code, Dr. Fung gives a number of tips when fasting.  Here are a few:

-Take cinnamon and eat chia seeds to reduce hunger.

-Drink salt water when you get dizzy.

-Take a magnesium supplement when you get muscle cramping.

-Drink salt water when you get headaches.

-Take Metamucil when you get constipated.

-Take a multivitamin because you won’t be getting any micronutrients on fasting days.

Maybe it’s just me, but having to do all of these things leads me to believe that fasting is neither a healthy or normal way for the human body to lose weight.

Is The Obesity Code Worth Reading?

Absolutely! It is important for me to read nutrition books that differ from my own personal philosophy. This book makes a lot of really good points. Levels of insulin have much to do with obesity. Limiting sugar and refined carbs are a huge part of the solution. Adequate sleep and limiting snacking are also big players. I would just add a bit to this good advice, notably; lift weights at least twice a week to build muscle, daily cardiovascular exercise is a huge part of weight loss, there is no need to fast, and lastly be sure to limit saturated fats and substitute them with more healthy vegetable fats.

What Can I Drink?

This is a question I get quite often from my own clients. If you are trying to lose weight, what you drink is as important as what you eat. Here are some guidelines:

Avoid

1) Any beverage with added sugar: This includes sodas and sports drinks. As you have probably heard, added sugar is a big part of weight gain for most of us and eliminating it is a big part of weight loss. Drinking calories is just a bad idea if you are trying to lose weight.

2) Fruit and vegetable juices: When you juice a fruit or vegetable, you are concentrating the sugars and eliminating the fiber. You end up with a drink that can spike your blood sugar and cause a reactive hypoglycemia that can increase hunger and subsequent energy intake. Similar to #1 above, these beverages also contain calories.

3) Drinks with artificial sweeteners: This includes diet soda and diet iced tea. Although these beverages are fine for an occasional treat, having them every day can perpetuate cravings for sugar and other refined carbohydrates. I advise my clients to have these kinds of drinks just a couple of times a week when they are allowed to cheat on their diet.

Allowed

1) Filtered tap or bottled water. A squeeze of a fresh lemon, lime or even an orange brings this to a whole new level.

2) Club soda. There are some really good unsweetened flavored club sodas on the market right now. In my opinion, Polar is the best.

3) Decaffeinated coffee or tea, either hot or iced.

Can the allowed beverages be considered boring? Maybe. You know what is not boring, hitting your goal weight.

The Critical Importance Of Weight Training

The Study

In this investigation, 160 obese men and women aged 65 or older were put on a low-calorie weight loss diet for 6 months. All of the subjects had mild to moderate frailty, which was defined by a test called The Physical Performance Test. Subjects were randomized to 1 of 4 groups; aerobic exercise, resistance training, a combination of aerobic and resistance exercise and a control group. The aerobic and resistance exercise sessions lasted 40 minutes and were completed 3 times per week. 

By the end of follow-up, body weight had decreased by 9% in all exercise groups. Other results were very interesting:

-The combination group significantly increased Physical Performance Test scores compared to the other groups.

-Peak oxygen consumption increased more in the combination and aerobic group than in the resistance group.

-Strength increased more in the combination and the resistance groups than in the aerobic group.

-Lean body mass decreased less in the combination and resistance group than in the aerobic group.

-Bone mineral density decreased less in the resistance and combination group than in the aerobic group. The New England Journal of Medicine 2017; 376:1943

Take Home Message

It is abundantly clear that the combination group showed the most improvement in functionality. The benefits of adding resistance training to your weight loss and cardio programs are undeniable. Perhaps the biggest benefit is that weight training reduces the decrease in lean body mass that occurs with weight loss. This makes it much easier to maintain your weight loss long-term.

Resistance training also has tremendous functional health benefits. While this is true for all of us, it is especially true for older adults, since most of the loss of functionality due to aging is related to the loss of muscle mass. It is really important for all adults to hit the weights at least twice per week. This is especially true for older adults.

Sleep Extension And Your Diet

The Study

Forty-two short sleepers (5 to <7 hours per night) were randomized to either a sleep extension or control group. The sleep extension group received a behavioral consultation designed to increase sleep duration. The trial lasted for 4 weeks and dietary intake was measured with a 7-day food diary.  

Post intervention, the sleep extension group significantly increased their sleeping period by 47 minutes per night. By the end of follow-up, the sleep extension group significantly reduced their intake of added sugars when compared to the control group (-9.6 grams/day vs. +.7 grams/day).  American Journal of Clinical Nutrition 2018; 107:43.

Take Home Message

There have been a ton of studies published in the last 10 years on sleep deprivation and weight gain. There is evidence that leptin levels drop and ghrelin levels rise with short sleep. The hormone leptin influences metabolism and the hormone ghrelin influences hunger. Therefore, if you are not sleeping enough, your metabolism will slow down and your hunger will increase. This is not a good combination for those trying to manage their weight. This study shows that getting enough sleep may help you improve the quality of your diet as well. Make sure you get at least 7 hours of sleep each night.

Product Review: Life Fitness X1 Elliptical Trainer

No matter what your fitness goal, it is critical to set up an environment where exercise is easy for you to accomplish. Nothing is easier than having exercise equipment in your home. Today’s review is for a piece of equipment that is near and dear to my heart. 

I have worked at a lot of gyms over the years. I have also belonged to a lot of gyms. The Life Fitness X1 Elliptical Trainer is the home version of my absolute favorite cardio machine of all time. I picked one up as soon as we moved into our new house a few years ago and let me tell you, it is awesome.

Pros
1) Extremely well made and durable: I have had mine for two years. My wife and I use it every single day and it looks like we just took it out of the box.

2) Variable intensity: There are 20 levels of resistance as well as computer guided workouts included with the X1.

3) Quiet: This machine is very quiet. I can work out while my wife is sleeping and she won’t know it.

4) Feels exactly like the more expensive commercial gym model. This is a great workout.

5) Extremely low impact: Elliptical training is my preferred mode of cardio for just about everyone. You burn a lot of calories with virtually no impact on your joints. It feels like you are running on air when on this machine.

6) Having any piece of cardio in your home allows you to avoid bad weather, which can make it very hard to get your cardio in consistently if you exercise outdoors.

Cons
1) On the expensive side. I found the best deal at Costco. At the time of this writing, it goes for $1899.99. This price includes both shipping and assembly. This is a pretty big initial investment, but if you divide it by the number of years you will have it, the X1 comes out to far less than you would pay in yearly dues to a nice gym.

2) It takes up a lot of space. Having said this, I would recommend putting it someplace that you will use it, such as your bedroom or your living room. Exercise machines put in a damp basement have a tendency to disappear from your life. It is also helpful to put it in front of a TV so you can combine your cardio with your TV time.

Do I Recommend The Life Fitness X1?
Absolutely. If you have the space and are able to make the financial commitment, there is no better option for cardio than this, in my opinion. You can check out this machine at Costco here.

If you don’t have the space for a big machine, or don’t want to spend the money, here is a review of the Gazelle Edge, a portable, much less expensive way to have an elliptical in your home.

Disclosure: I am not affiliated with the company that makes the Life Fitness X1 Elliptical Trainer and make no money if you buy it.

Which Diet Is Most Effective; Low Fat, Low Carb Or Mediterranean

The Study

In this well-designed trial, 322 overweight subjects were randomly assigned to either a low fat diet, a low carb diet or a Mediterranean diet for 2 years. By the end of follow-up, the low fat group had lost 6.4 lbs, the Mediterranean group had lost 9.7 lbs. and the low carb group lost 10.3 lbs. There were some other interesting results:

-The low carb diet was the toughest to adhere to and had the highest drop-out rate.

-The Mediterranean diet had a more beneficial impact on blood glucose and insulin levels in diabetics than the low fat or low carb groups.

-Several risk factors for heart disease improved more on the low carb and Mediterranean diets than on the low fat diet, including reductions in c-reactive protein, triglycerides and ratio of total to HDL cholesterol. The New England Journal of Medicine 2008; 359:229

Take Home Message

The research is really starting to show that a low fat diet is not the path to greater weight loss or improved health. This trial was extremely well designed and not only was the low fat diet less effective for weight loss, it did not improve risk factors for heart disease and diabetes as much as the other two approaches. 

It is important to note that the subjects on the low carb diet were instructed to eat vegetable sources of fat and protein. This was not your typical low carb diet where the subjects were eating bacon, steaks and full fat dairy all day. In fact, when you choose healthy sources of protein and fat, the low carb diet looks a lot like a Mediterranean diet.

For me, the take home messages of this study are:

#1) Healthy fat is a good thing and does not need to be tightly restricted whether your goal is improved health or weight loss.

#2) Too many rapidly absorbed carbohydrates in your diet can make it harder to lose weight and can have a negative impact on your health. 

Is Alternate Day Fasting The Best Way To Lose Weight?

The Study

The efficacy and safety of alternate day fasting as a method of weight loss has not been proven despite the popularity of this weight loss strategy. A study recently published in JAMA Internal Medicine attempts to answer this question. In this investigation, 100 subjects were randomly assigned to one of three groups:

Alternate day fasting: these subjects consumed 25% of their energy needs on “fast days” and then 125% of their energy needs on alternate “feast days”.

Calorie restriction: these subjects consumed 75% of their energy needs each day.

Control group: these subjects had no intervention.

The trial consisted of a 6-month weight loss phase and then a 6-month weight maintenance phase. Primary outcome measures were weight loss and risk factors for heart disease. The results were fascinating:

1) Drop out rates were higher in the fasting group when compared to the calorie restriction group (38% vs. 29%).

2) There were no significant differences in weight loss between the two groups by the end of follow-up.

3) Mean LDL cholesterol rose significantly in the alternative day fasting group.

JAMA Internal Medicine 2017; 177:930-38.

Take Home Message

The results of this well-designed trial are not encouraging for proponents of alternative day fasting. Compared to a more conventional approach, fasting did not improve weight loss, was more difficult to follow and even had a negative impact on health, as higher LDL cholesterol translates to an increased risk of cardiovascular disease. 

Other studies I’ve reported on in this blog have shown evidence of glucose dysregulation with fasting (see them here). While we will wait for more research to be conducted in this area, it appears that fasting is not the way to go if weight loss and improved health are your goals.

Late Night Eating And Weight Gain

The right diet, a good cardiovascular exercise program and a full body resistance training program form the foundation of any weight loss strategy. However, other lifestyle choices can have a big impact on weight loss success. An example of one such lifestyle choice is to limit eating after 8:00 PM. This has been recommended to dieters for generations, but is there any research to back this up? Do people who eat a lot of food after 8:00 PM really gain more weight? In this post, we’ll take a look at what the research tells us.

I find this topic interesting for a couple of reasons. First of all, when I was in high school and college, I could not gain weight for the life of me. I ate all the time, but I had a really high metabolism and was extremely physically active, so I burned off every calorie I put into my body. This probably sounds like heaven to people who were struggling with their weight, but it wasn’t so great. I was really, really skinny.

One of my fraternity brothers told me that to gain weight, I just had to eat 2 peanut butter and jelly sandwiches right before I went to bed. I told him that those few hundred calories wouldn’t make a difference because I was already eating a ton of calories all day. He said it wasn’t just the extra calories, it was when I was eating them that was so important. I gave it a shot. The summer between freshman and sophomore year in college, I ate 2 peanut butter and jelly sandwiches right before I went to bed. I was also working in construction and lifting weights. I put on 30 lbs. in 4 months!

When I became a licensed nutritionist and started working with weight loss clients, I found that a lot of people who were overweight ate a high percentage of their food at night. Having them stop this habit, in addition to changes in diet and exercise, helped them to lose weight. I also noticed that clients that made good progress with their diet and exercise but did not stop eating late at night did not lose much weight at all. I have been recommending to limit late night eating to my weight loss clients for over 15 years.  So what does the research have to say about this?

The Research

Surprisingly, I did not find much high quality research on the topic of late night eating and weight gain. However, I did find several investigations utilizing weaker study designs that hint at a potential association.

1) In a recent cross-sectional investigation published in the American Journal of Clinical Nutrition, 110 college-aged men and women recorded all of their food intake with a time stamp so that the hour of consumption could be accurately recorded. When compared to normal weight subjects, overweight subjects consumed significantly more of their calories 1 hour closer to melatonin onset, which was around 11 PM (Reference 1).

2) Another cross-sectional investigation published in the journal Appetite showed that protein, fat and carbohydrate consumed after 8:00 PM were associated with a higher BMI in a group of 52 volunteers that filled out 7 day food logs (Reference 2).

3) This investigation is a much older study that only had an abstract. I include it here because it is interesting and I have never seen results like this before. In this study, 9 young men were given the same meal at 9:00 AM, 5:00 PM and 1:00 AM (Reference 3). Energy expenditure was measured by indirect calorimetry for one hour before, and six hours after consumption. Dietary induced thermogenesis (DIT) of the meal was calculated as the 3 hours of energy expenditure above basal metabolic rate.

Morning DIT was significantly higher than afternoon DIT (P=.04) and night DIT (P=.0002). Afternoon DIT was higher than night DIT (P=.06). What this means is that these young men burned a higher percentage of their meal’s calories in the morning than they did in the afternoon or at night.

Conclusions And Recommendations

The research on late night eating and weight gain is largely unimpressive. To come to a firm conclusion, you’d really want to see a number of randomized trials and well-designed cohort studies showing an association with late night eating and weight gain. To my knowledge, these studies have yet to be conducted. 

What we are left with are cross-sectional studies that are a much weaker form of evidence. Having said that, several studies I did find suggest a cross-sectional association between eating late at night and gaining weight. One study was a trial that mentions a potential mechanism, but it is so old I could not find the full text to properly evaluate it.

I would say the evidence, while weak, is suggestive of a relationship between late night eating and weight gain. So what are some potential mechanisms at play here?

1) Eating food late at night simply adds extra calories that you would not consume otherwise. 

2) Food consumed late at night is of poor nutritional quality and more likely to cause weight gain. Most people snack on high glycemic carbs like chips, pretzels and dessert late at night. These calories spike the blood sugar and increase fat storage.

3) Another hypothesis is that our metabolism slows down quite a bit at night, so more of what we consume is stored as fat.

4) The thermic effect of food is lower at night, so more of what we eat is stored as fat.

Despite the weak forms of evidence and uncertain mechanisms, I still think it is a good idea to limit eating after 8:00 PM if weight loss is your goal. I have seen this be a very big part of the equation for many weight loss clients over the years.

References

1) McHill AW, et al. Later circadian timing of food intake is associated with increased body fat. American Journal of Clinical Nutrition 2017; 106:1213-19.

2) Baron KG, et al. Contribution of evening macronutrient intake to total caloric intake and body mass index. Appetite 2013; 60:246-51.

3) Romon M, et al. Circadian variation of dietary induced thermogenesis. American Journal of Clinical Nutrition 1993; 57:476-480.

Late Night Eating And Weight Gain

The Study

Late night eating is considered a risk for weight gain. However, there has been little research published in this area. In this investigation, 110 college-aged men and women recorded all of their food intake with a time stamp so the hour of consumption could be accurately recorded. When compared to normal weight subjects, overweight subjects consumed significantly more of their calories 1 hour closer to melatonin onset, which was around 11 PM.  American Journal of Clinical Nutrition 2017; 106:1213-19.

Take Home Message

This is a very interesting study. I have noticed for years that my clients who eat late at night don’t seem to lose much weight. The authors of this study were not quite sure why late night eating was associated with weight gain. One hypothesis is that the thermic effect of food decreases late at night. This would translate into more calories being available for fat storage in comparison to the same meal eaten earlier in the day.

Although this investigation is a cross-sectional study, which is considered a weaker form of evidence, I think there is something here. I always have my clients finish eating by 8:00 PM if they are trying to lose weight.  

Grip Strength And Mortality

The Study

In this interesting study, 403,199 members of the UK Biobank Study had their grip strength measured and were followed for 7 years. After controlling for all known confounders, including body mass index, men with the highest grip strength had a 32% lower risk of mortality compared to men with the lowest grip strength. Women with the highest grip strength had a 25% lower risk of mortality compared to women with the lowest grip strength. The American Journal of Clinical Nutrition 2017;106:773-82.

Take Home Message

Grip strength is a pretty good indicator of total strength. This study shows us that the stronger you are, the healthier you are. A possible mechanism at play here is improved glucose metabolism and insulin sensitivity in subjects who regularly lift weights. There is also evidence that weight lifters have improved blood lipid profiles. Resistance training is an often overlooked aspect of health and fitness.  Try to hit the weights at least twice a week and preferably three times a week.  You don’t have to lift heavy weights or spend a lot of time, a simple 20-30 minute full body workout with lighter weights will get the job done nicely.

Book Review: Eat, Drink And Be Healthy

Next up for review is Eat, Drink And Be Healthy, which is an updated 2^nd edition of the original work published in 2001. The author, Dr. Walter Willett, is a Professor of Epidemiology and Nutrition at the Harvard School of Public Health. He was the director of the nutrition department at Harvard when I was in grad school. It was an honor to learn from him and you will not find a more impressive and respected nutrition researcher anywhere in the world.

Introduction

This book is basically a nutrition research encyclopedia, summarizing the most important literature of the past few decades. Dr. Willett organizes the book into 7 diet and lifestyle recommendations that have a powerful impact on risk of chronic disease. The book is 378 pages long. It is extremely well written and researched and I truly enjoyed reading it.  This is the best nutrition book I have ever read and the original version is the 2^nd best nutrition book I have ever read.

5 Things I Really Liked About Eat, Drink, And Be Healthy

1) The best thing about this book is that all of the recommendations are based on scientific evidence. There is not a person in the world that understands nutrition research as well as Dr. Willett. He is considered the father of Nutritional Epidemiology and this book is a bible of nutrition research. So many popular diet books make recommendations based solely on the opinion of the author. It is so very nice to read a nutrition book making recommendations that are based on peer-reviewed evidence.

2) The chapter on dietary fats is amazing. There has been a lot of confusion lately about which fats are healthy and which are not that has been generated by popular diet books and the media. Dr. Willett sets the record straight.

3) If you have worked with me personally or read any of my books, you already know that carbohydrate quality is of extreme importance to me. Dr. Willet does an amazing job with his chapter on carbohydrates.

4) I really liked the section on how to decipher nutrition research. The media does a horrible job when disseminating new nutrition research. Their goal is clearly to generate buzz and sell newspapers and they often completely misinterpret research findings. Dr. Willett explains the process of the scientific method and how it is normal and fine to get contradictory results from nutrition research from time to time. Recommendations should never be altered based on just one study. You always want to look at a new study in the context of research done in other populations and with different study designs. Willett really does a good job explaining this.

5) The chapter on weight loss diets is outstanding. Willett goes through each of the popular diet strategies out there and expertly lists the pro’s and con’s of each. This is probably the coolest part of the book, in my opinion.

Is Eat, Drink And Be Healthy Worth Reading?

Absolutely! As I mentioned above, if you could read just one book on nutrition, this would be it. Dr. Willett has changed the way we conduct nutrition research and millions have benefitted from his work. I think this book should be required reading for all high school students. There are very few books out there that can actually change the course of your life after reading them, this is one of them.