Feature Article: Saturated Fats: Harmless After All?

The impact of saturated fat on health is a controversy that has been brewing for some time in the field of nutrition. Early research based on animal investigations, ecological observations and controlled feeding studies looking at serum cholesterol supported a major, negative effect of saturated fat on risk of coronary heart disease. 

More recently, there has been some research that may call this into question.  For example, certain classes of saturated fats have been shown to have different effects on our health than others. Furthermore, saturated fat has been shown to be more or less harmful depending on what you eat in its place.  For years, proponents of low carb and paleo diets have been saying that saturated fat is mostly harmless and that the real enemy is carbohydrates.  Some people even take coconut oil (which is a saturated fat) as a health supplement.  So what’s the story here?  Is saturated fat as bad for you as we thought or can you feel free to load up on butter and steaks without risking your heart?  Let’s clear the air.

What Are Saturated Fats?

Saturated fats are fats that contain no double bonds.  All of their carbons are saturated with hydrogen.  They are found, for the most part, in animal products.  Sources of saturated fat include butter, cheese, whole milk, steak, bacon, hamburgers, pepperoni and other fatty meats.  There are also a couple of vegetable sources of saturated fats, most notably coconut oil and palm oil. 

Symposium On Health Effects Of Saturated Fat

In light of the recent questions concerning saturated fats, an expert panel was put together to weight the evidence.  There were some pretty impressive researchers on this panel, including Harvard’s Dr. Walter Willett and Dr. Frank Hu.  The members of the panel reviewed the literature and came up with a consensus opinion on the health effects of saturated fat.  They published their findings in the American Journal of Clinical Nutrition (Reference 1).

Here are some of the key findings:

1) The risk of heart disease is decreased when polyunsaturated fats replace saturated fat in the diet.  For every 1% of energy from saturated fats that are replaced with polyunsaturated fat, the risk of heart disease is reduced by 2-3%.  This is mostly due to the lowering of LDL cholesterol.

2) No clear benefit has been shown for substituting carbohydrates for saturated fat.  However, this may be due to the fact that so much of the carbohydrate consumed in the US is refined and high glyemic load.  These types of carbs tend to lower HDL cholesterol and raise triglycerides.  Evidence is suggestive that replacing saturated fat with low glycemic load carbohydrates significantly reduces risk of heart disease.

3) Replacing saturated fat with refined carbohydrates decreases HDL and LDL particle size (smaller LDL particles are more atherogenic than larger ones) and increases triglycerides.  These changes are quite harmful when it comes to risk of heart disease.

4) It is difficult to tell the effects of monounsaturated fats because in the US, a large percentage of monounsaturated fat is consumed in the form of beef and dairy.   Having said this, the research is suggestive that replacing saturated fat with monounsaturated fat will reduce risk of heart disease.

5) Individual saturated fats have different physiological effects.  Stearic acid tends to be less harmful than other types of saturated fat.   Regarding cholesterol raising effects, stearic acid appears to be neutral where other saturated fats (12:0, 14:0 and 16:0) raise LDL and HDL cholesterol.  C-14 appears to have the most negative effect.

6) There is not enough evidence to judge if short and medium chain saturated fats are harmful.

Take Home Message

So, at the end of the day, saturated fat is still pretty bad for you and it's a good idea to limit it in your diet.  If you replace saturated fat with polyunsaturated fats or monounsaturated fats your risk of heart disease is reduced significantly.  You’ll find these types of fats in vegetable oils, nuts, seeds and avocados.  If you replace saturated fat with low glycemic carbohydrates, it looks like you will also reduce your risk of heart disease.  On the other hand, if you replace saturated fats with the wrong type of carbs like white bread, pasta, white rice and sugar, you may actually be worse off.   The take home message is that the wrong type of dietary carbohydrate is as harmful as the wrong type of dietary fat.  If you’ve read my book or work with me privately, this is old news to you!

Reference

1) The role of reducing intakes of saturated fat in the prevention of cardiovascular disease: Where does the evidence stand in 2010? The American Journal Of Clinical Nutrition 2011;93:684-88.

Research Update: Mediterranean Diet Vs Low Fat Diet For Weight Loss

A Randomized Controlled Trial Of A Moderate Fat, Low Energy Diet Compared With A Low Fat, Low Energy Diet For Weight Loss In Overweight Adults
McManus K, et al.
International Journal of Obesity 2001 25:1503-11.

Objective: To compare the efficacy of a low fat diet and a moderate fat diet for long term weight loss.

Study Population: 101 overweight men and women (BMI between 26.5 and 46).

Methods: Subjects were randomized to one of two weight loss interventions.  Both diets had a goal of 1200 calories per day for women and 1500 calories for men.  Both diets provided 15-20% of calories as protein.  The low fat diet provided 20% of calories as fat and 60-65% of calories from carbohydrate.  The moderate fat diet provided 35% fat and 45-50% carbohydrate.

Everything else about the interventions was identical, including physical activity recommendations, behavior modification advice, weekly nutrition counseling sessions and the recording of food to gauge compliance.  Measurements included body weight, BMI, waist and hip circumference, physical activity and nutrient intake.  These were taken at baseline, 6, 12 and 18 months.

Results: 1) After 18 months, the moderate fat group had lost 9.2 pounds, decreased their BMI by 1.6 points and decreased their waist circumference by 2.7 inches.        2) During this same period, the low fat group gained 6.4 pounds, increased their BMI by 1.4 points and increased their waist circumference by 1 inch.  3) After 18 months, only 20% of the low fat group was actively participating in the weight loss program while 54% of the moderate fat dieters were sticking with their plan.

Discussion: This is a beautifully designed study.  First of all, it was 18 months long so you can assess both weight loss and maintenance of lost weight.  All elements of the weight loss interventions were identical, including total calories, total protein, physical activity and the dietary counseling component.  The only difference between the two interventions is that one was low fat, high carb and the other was moderate fat, moderate carb.

The results are striking.  After 18 months, the moderate fat group was 15.6 pounds lighter than the low fat, high carb group.  It is also notable that only 20% of the low fat dieters were able to stick to their program long term, while over 50% of the moderate fat dieters were able to stick to their program.  This is the knock on low fat diets in general.  Early on, you can lose some weight with them, but it appears that most weight is regained fairly quickly.  It seems that people have a hard time sticking to the low fat plans.  This is most likely due to the increased hunger caused by the dramatic swings in blood sugar on these diets.

Take Home Message: Fat is not the enemy, people.  When chosen wisely with vegetable source of fat, a moderate fat diet (35% of calories) can help reduce the risk of heart disease and diabetes and even help you maintain your weight.  Losing weight is great, but keeping it off is better.  The research is beginning to mount that a moderate fat diet gives you a better chance of keeping your weight off than a low fat diet.

Questions And Answers: Running

I always get a lot of questions on cardio in general and running in particular, so I thought running would make a great topic for my next Q and A.  As always, if you are initiating an exercise program, check with your doctor to make sure it is safe to do so.

Is running a good exercise for weight loss?

Yes and no.  As far as its effectiveness, running is great for weight loss.  You burn a ton of calories.  However, it is high impact and over time can be very tough on the body.  When we run, we put up to 6 times our body weight on our joints.  I’m about 190 lbs, so when I run, I’m pounding my knees, hips, back and ankles with the equivalent of over 1100 pounds of joint stress!  I don’t think our bodies were designed to deal with this level of impact, particularly if you run long distances multiple times per week.  I have found if someone runs long enough and far enough, year after year, they will surely have to deal with some major overuse injuries that can have a negative impact on their ability to engage in physical activity as they age.

I think I want to run a marathon, should I?

I always try to talk my clients out of running marathons.  I get the challenge and sense of accomplishment that goes with running one, but I just don’t think it’s safe.  I’ve already covered the joint stress issue.  Another issue is the effect of that amount of exercise on immune function.  The graph of exercise and immune function is J-shaped.  Your immune system starts to improve with increasing exercise.   However, after a point, immune function starts to decline with increasing exercise.  It even gets to a point below the baseline.  What that means is exercising too much can be worse for your immune system than not exercising at all.  Ever notice how most marathon runners get an upper respiratory infection after the race?  I’m not a fan of any activity that depresses immune function. 

What if I just love to run?

I’ve worked with enough clients over the years to know that running is really addicting and many people will do it despite my recommendation not to.  In this case I would suggest a modified run/walk program.  What I have them do is run for 2 minutes at a pace a little faster than normal and then follow this with 3 minutes of brisk walking.  This interval is repeated throughout the cardio session.  With this strategy, you get the increased calorie burn of running but also break up the impact of continuous running.

Do you advise your clients to run?

Never, I always try to talk them out of it.  If they persist I suggest the run/walk program described above.  I also let them know about lower impact forms of exercise like elliptical training.  This form of exercise will give you a similar calorie burn while protecting the joints. 

Book Review: The China Study

The China Study by Dr. T. Collin Campbell is next up for review.  Dr. Campbell is an accomplished researcher who is a Professor in Nutritional Biochemistry at Cornell University.  Dr. Campbell has published a ton of research papers and has served as a member on a number of government nutrition and health committees.  He is probably most well known for his work on the China Study, which is an ecological study of nutrition and disease among 6,500 people across China.  The focus of this book is what Dr. Campbell learned from the China Study.

Introduction

Dr. Campbell strongly believes that we should eat a very low fat, low protein diet devoid of all animal products.  If you read this blog regularly or have read my book, you know I am not a low fat or vegetarian guy.  In fact, I feel that low fat diets can have a negative impact on our health due to their resulting high glycemic load.  However, in the young field of nutritional epidemiology, I believe it is important to read work that goes against your own personal views to further understand the controversies that make this field so interesting and thought provoking.  The book presents a lot of Dr. Campbell’s research on nutrition and disease.  He then tells you what foods to eat, and goes into a detailed explanation of the problems with nutrition research and policy at both the academic and government level.  Overall the book was well written and an interesting read.

5 Things I Liked About The China Study

1) Points out the dangers of red meat and saturated fat.  One thing we have all learned from low fat diet advocates is that saturated fat and lots of red meat can be harmful.  This book is no exception.

2) Emphasis on fruits and vegetables.  Fruits and vegetables are the best things we can eat to improve our health.  This is stressed throughout the book.

3) Emphasis on whole grain foods.  While I’m not a high carb guy by any stretch, I realize the importance of whole grains in our diet.  The literature is teeming with evidence that whole grains improve our health and reduce risk of heart disease, stroke, diabetes and certain cancers.

4) De-empahsizes dairy products.  Those of you who know my writing know that I’m not a huge fan of dairy. 

5) Nutrition policy section  As a member of a number of government committees on nutrition policy, Dr. Campbell can relate his first hand experience on the competing interests of academia, the food industry, research science and the government’s influence on our food policy recommendations.  I found this section a very interesting read.

What I didn’t agree with in The China Study

1) This books groups all fats as unhealthy.  While certain fats are unhealthy (saturated fat and Trans fat) other fats like mono-unsaturated fat, poly-unsaturated fat and omega 3 fatty acids are extremely health promoting.  I don’t know why he didn’t differentiate the different classes of fats.

2) This book groups all animal proteins as unhealthy.  There is a very big difference in how chicken, salmon, turkey and egg whites treat our bodies when compared to steak, bacon and hot dogs.  Some animal proteins are bad for you and some are not.

3) Very high carbohydrate diets have recently been shown to have a negative impact on HDL cholesterol and triglycerides when compared to more Mediterranean style diets.  This isn’t mentioned anywhere in the book.

4) Very high carbohydrate diets result in a high dietary glycemic load.  The glycemic load has been associated with a variety of diseases in the past 10 years.  There was no mention of this anywhere in the book or even of the glycemic load as a concept.

5) His criticism of the Nurse’s Health Study was baffling.  He feels that NONE of the research out of Harvard tells us anything because of flaws in the design of the study.  I had a hard time understanding this argument.  His study is ecological in nature, follows 6,500 Chinese citizens and measures diet one time via a 3 day food record and he has total confidence in the results.  The Nurses’ Health Study is a prospective cohort study, follows 120,000 American nurses for over 30 years and measures diet by means of a validated food frequency questionnaire that is updated every 4 years to reflect changes in diet.  Every aspect of the Nurses’ Health Study is superior to the China study yet it is given no respect in this book. 

Is The China Study Worth Reading?

Absolutely.  I enjoyed the book and learned a lot.  At the end of the day, low fat diet advocates taught us a lot about a healthy diet: the dangers of saturated fat, red meat and dietary cholesterol as well as the benefits of fruits, vegetables and whole grains.  However, well designed research has added a lot to our understanding about the benefits of healthy fats, lean animal proteins, fish and other sources of omega 3’s and most importantly, a low glycemic load diet. 

Research Update: Sleep and snacking and disturbing news about omega 3’s

Dietary omega-3 fatty acids and fish consumption and risk of type 2 diabetes

American Journal of Clinical Nutrition 2011 93:143-50

This study looked at the association between omega 3 intake and risk of type 2 diabetes. Over 36,300 women from the Women’s Health Study were followed for 16 years and during this time there were 2,370 new cases of type 2 diabetes.  Women who consumed the most marine based omega 3’s (.43 grams a day) had a 44% increased risk of type 2 diabetes compared to women who consumed the least (.07 grams per day).  A similar increased risk was found for women who consumed the most fish (4 servings per week) compared to women who consumed the least (1/2 serving per week).

Take Home Message:  This is a very significant finding.  People are going nuts about omega 3 supplementation.  Omega 3’s have been shown to have extremely beneficial effects on risk of heart disease, which is great, but here is evidence that going overboard has the potential to hurt you.  This is not the first study to show an adverse effect of high amounts of omega 3.  Several other well designed studies have shown higher glucose levels and decreased insulin sensitivity in type 2 diabetic patients with large doses of omega 3 fatty acids.   Get your omega 3’s through your diet, as nature intended, by eating a variety of seafood meals 2-3 times per week.  My clients and those who have read my book know that I am not a fan of supplementation in general.  Too many times concentrated nutrients in large dose supplement form create unexpected consequences in humans.  Get your nutrients through your diet and you’ll have nothing to worry about.

Sleep curtailment is accompanied by increased intake of calories from snacks

American Journal of Clinical Nutrition 2009; 89:126-33

This is a beautifully designed little study on sleep deprivation and subsequent energy intake.  Eleven healthy subjects slept in a sleep lab for 14 days on two separate occasions.  The sleep lab is a controlled environment where physical activity, sleep and energy intake can be strictly monitored.  The subjects were given unlimited access to as much food as they wanted.  On the first 14 day visit they were restricted to 5.5 hours of sleep a night. On the second 14 day visit, they were allowed to sleep 8.5 hours per night.  Besides the amount of sleep, everything else about the two interventions was identical.  The amount of food they ate throughout the two interventions was measured and compared.  When the subjects slept only 5.5 hours a night they consumed 297 more calories per day!

Take Home Message: Get your sleep!  That rate of caloric consumption would result in a weight gain of 1 pound every 12 days.   Several studies have shown that a lack of sleep increases ghrelin levels (a hormone that influences appetite) and decreases leptin levels (a hormone that influences metabolism).  This must not be the whole story because in this study there was no difference in leptin and ghrelin levels.   More research is needed to elucidate the mechanisms at play here but the message is clear: Get your sleep.

Product Review: PT Pro Portable Fitness Bench

I’ve been working with weight loss and fitness clients for over 15 years.  One thing that I have noticed over the years is that people who work out at home do a much better job at sticking with their routine than those that go to a gym.  This is for a few reasons.  Number one is a time issue.  If you have to get in your car, drive to the gym, get changed in the locker room and then do the same thing in reverse, you may have just turned your 40 minutes workout into an hour and 20 minute ordeal.  It’s just too easy to blow off. 

Also, somewhere along the way, gyms became really expensive!  Many gyms here in the Boston area are $70, $80 or even $100 dollars a month.  This adds up.  If you are spending $80 a month for your gym, that is $960 per year or $4800 in 5 years.  If you took 50% of one years gym fees, you can set yourself up with a home gym that will last for decades!

A great start for any home gym is a set of dumbbells and an exercise bench.  Enter the PT Pro Portable Fitness Bench.  This bench is perfect for people that don’t have a lot of space and/or don’t want to look at their exercise equipment on a regular basis.

Here are some of the features and benefits of this bench

#1) It folds up for storage.  The legs of this bench fold up so you can store it in a closet.  This is a great feature if you live in an apartment and don’t want your bench taking up valuable space.

#2) For fitness professionals; it is highly portable.  The bench is lightweight and you can bring it to a client’s home if you are an in-home trainer.

#3) The bench has both incline and decline capabilities so you can add a lot more variety than you can with a simple flat bench.

#4) It is very well made.  I’ve had mine for years and it is holding up extremely well.  In fact, it looks and works as well today as the day I got it.

Cost: It is not cheap at $299 but it is a one time expense, you’ll likely never have to buy another bench.  It’s also a cost saver if it allows you to cancel your gym membership. 

For more information, here’s the manufacturer’s website: http://www.jpdesignandmfg.com/dbID/20.html

I recommend it highly.

Livestrong

As some of you may know, I recently was hired as a free lance writer for Livestrong.com.

Livestrong is a great site that features a ton of useful health, fitness and nutrition information.  It gets over 6 million hits a month!  I figured that I’d share my last 3 articles that were published on livestrong.com as this blog post.

#1) Why is week 2 of weight loss so hard?  In this article I detail some of the reasons that week 2 of weight loss is not as successful as week 1.

#2) The best all around exercise machine? In this article I declare one exercise machine as the king of them all.  Spoiler alert: it’s the elliptical trainer.

#3) Why aren’t I losing weight on my gazelle?  This article explores how to use the Gazelle Exercise Glider optimally for weight loss.

I hope you enjoy the articles and the site and let me know what you think!