Friday, September 13, 2019

Can I eat raisins?

This is a question I get from new clients all the time. Since raisins are a form of fruit, it makes sense that people think that they are a good choice as a snack or as part of a meal.
While it is true that fruits in their whole and natural form are great to include in your diet in abundance, a lot changes about a grape when it is dried into a raisin. 
The drying process tends to increase the sugar in a fruit. This transformation dramatically changes the way that raisins impact our blood sugar.
Let’s compare an apple to raisins. The glycemic index of an apple is quite low at 34, while the glycemic index of a raisin is 64. The glycemic load of an apple for a 120 gram serving is 5, while the glycemic load of a 60 gram serving of raisins is 28.   
Glycemic index and glycemic load are measures of how a food impacts our blood sugar. Generally speaking, the lower this number, the easier the food will be on your blood sugar.
Whether your goal is to lose weight, improve your health or increase your energy, keeping your blood sugar stable is absolutely critical. Raisins make it difficult to do this. Limit raisins and other dried fruits and focus on whole, fresh fruits that are not processed in any way.

Portion size and caloric intake in children

The Study
Does the amount of food on your plate influence the amount of calories you ingest? A recently published study in children attempts to answer this question. Forty-six children aged 3-5 were served the same 5 day menus on two separate occasions. The first was with normal portion sizes. In the second, portions were increased by 50%.

When the children had more food on their plate, they ate an additional 167 calories, which was a statistically significant increase of 18%. Overweight children showed an especially strong response to the larger portions. American Journal of Clinical Nutrition 2019; 109:1361-72.

Take Home Message
While the results of this study are particularly important to parents of pre-school children, I believe that they apply to all of us. When there is more food on our plate, we all tend to eat more. This is a big reason why people who eat out a lot at restaurants tend to gain weight.

There are really 2 take home messages here:
-Serve a reasonable amount of food on your plate in the kitchen and bring your plate to the table. If you see a big dish of food in front of you, you will be way more likely to load up with a second portion.

-Limit eating out at restaurants to just a few times per week. Portion sizes at restaurants are almost always greater than what you would make for yourself at home.

Non-nutritive sweeteners and body weight

The Study
The impact of non-nutritive sweeteners on body weight is controversial. In this study, 154 subjects were randomized to one of 5 groups and consumed 1.5 liters per day of a beverage made with either sugar, sucrolose (Splenda), aspartame (Equal), saccharin (Sweet and Low) or rebaudioside A (another non-nutritive sweetener). The beverage was consumed daily for 12 weeks. The results were fascinating:

 -Subjects consuming the sugar sweetened beverage gained 4.1 pounds by the end of the 12 weeks.

 -Subjects consuming the saccharin (Sweet and Low) beverage gained 2.6 pounds by the end of the 12 weeks.

 -Subjects consuming the sucrolose (Splenda), aspartame (Equal) and rebaudioside A had no significant change in body weight.

-When compared to all of the other non-nutritive sweeteners, the sucrolose (Splenda) group lost a statistically significant 3 pounds. American Journal of Clinical Nutrition 2019;109:1288-1301.

Take Home Message
There are really 2 take home messages here, one is not surprising while the other is quite surprising.

-It is not surprising that drinking a sugar sweetened beverage for 12 weeks puts weight on you. That is exactly what happened in this investigation.

-The idea that different non-nutritive sweeteners have distinct impacts on our weight is completely novel. This is the first study that I have seen that shows this and I think it will initiate a lot of research on in this area. In this study, Sweet and Low resulted in significant weight gain, Splenda in significant weight loss. Equal didn’t impact weight in either direction. While this is just one study, there may be something interesting here. We’ll stay tuned for further research in this area. 

What is worse for your health: regular or diet soda?

Nobody mistakes sugar for health food, but the serious impact it has on our health is just beginning to reveal itself in the research literature. For many people, diet soda is an agreeable alternative to sugar sweetened beverages, but the question arises; is diet soda any better for you than regular soda? A fascinating new study out of Harvard University helps us answer this question.

The Article
In this investigation, 37,716 men from the Health Professional Follow-up Study and 80,647 women from the Nurses’ Health Study were followed for 28 years (Reference 1). Sugar sweetened and artificially sweetened beverages were measured repeatedly throughout the follow-up. The outcomes were risk of cardiovascular death, cancer death and death from any cause. Here are some of the more interesting findings in this important study:

 -When compared to subjects that rarely drank soda, subjects who drank 2 or more sodas a day had a 21% higher risk of mortality, a 31% higher risk of cardiovascular disease and a 16% higher risk of cancer.

 -When compared to subjects that rarely drank diet soda, subjects who drank 2 or more diet sodas a day had a 4% higher risk of mortality and a 13% higher risk of cardiovascular disease. Diet sodas were not associated with risk of cancer.

 -Substituting one diet soda per day for one regular soda per day reduced risk of total mortality by 4%, cardiovascular disease mortality by 5% and cancer mortality by 4%.

Conclusions And Recommendations
This is a very well done study that tells us a lot. The take home messages here are the following:

1) Sugar is really harmful to our health. This study shows us an increased risk of disease and mortality with even moderate consumption. A statistically significant increased risk of mortality was found with just 2-6 servings per week. Sugar is also really addictive. The best advice is just to avoid it completely.  In the context of a blood sugar stabilizing diet, after 2 weeks, you won’t even miss it. I know this last sentence sounds hard to believe, but in my own experience and that of my clients, it is absolutely true.

2) Diet soda was far less harmful to our health. This may be a surprise to a lot of people who believe that artificial sweeteners are more or less a poison. They are actually quite well tested and well-designed research studies (such as this) have shown that they are safe, especially when consumed moderately.

3) A couple of notes when comparing regular soda to diet soda:

 -When comparing extreme quintiles, regular soda had over 5 times the risk of mortality than diet soda.

 -Diet soda was not associated with risk of mortality in those that consumed it moderately, which was less than 2 servings per day.

 -There was no association between diet soda and mortality in men, regardless of how much was consumed. The association was only seen in women.

As far as recommendations, there are 2:

1) Avoid sugar sweetened beverages, they are harmful to our health and are addictive. 

2) An occasional diet soda can be a real treat. Just don’t go overboard. Diet soda can perpetuate cravings for sweet foods and due to the cephalic response, may trick the body into releasing insulin. I generally tell my clients that they can include artificial sweeteners on their cheat meals, which is 2 meals per week. The rest of the time, drink water, decaf coffee/tea and my personal favorite, flavored club soda.

1) Malik VS et al, Long term consumption of sugar sweetened and artificially sweetened beverages and risk of mortality in US adults. Circulation 2019; 139:2113-25.

Saturday, July 13, 2019

Does skipping breakfast make it harder to lose weight?

The Study
For decades, people trying to lose weight have been told that skipping breakfast will seriously hurt their efforts. A recently published meta-analysis put this theory to the test. A meta-analysis combines the findings from several trials and produces a summary estimate of the results. This particular meta-analysis included 13 randomized trials. The results were both interesting and surprising. There was a slight weight loss benefit to skipping breakfast. Subjects randomized to a breakfast skipping group lost about 1 pound more than subjects randomized to a breakfast eating group. The breakfast skippers also had an average of 260 fewer calories consumed per day. British Medical Journal 2019; 346:142.

Take Home Message
Before we all start skipping breakfast, lets take a deep breath. While this study is interesting, the trials only lasted between 24 hours and 16 weeks. This is a very short time for weight loss studies. If there was a drop in resting metabolic rate with skipping breakfast, it may not appear until after this amount of time. In fact, this paper mentions that longer term observational studies have shown a weight loss benefit to eating breakfast.

Despite these interesting results, I still recommend eating breakfast for the following reasons:

-If you eat dinner at 6 in the evening, skip breakfast the next morning and have lunch at noon, you have gone 18 hours without food. My concern with this amount of time fasting is that your body will go into starvation mode and start to reduce resting metabolic rate. There is evidence in the research literature that fasting can decrease resting energy expenditure, as well as have a number of other effects that decrease weight loss efficacy. (Take a look at some of this research here)

-If you are only eating twice per day, it is really hard to get enough protein, healthy fats, fruits, vegetables, vitamins and minerals.

-Your mood, focus, energy and attention will be better if you eat breakfast. 

There are lots of good reasons to eat breakfast. Although this is a very interesting study, I wouldn’t let it change your mind about the importance of this meal.

Is snacking a good idea if you are trying to lose weight?

The Study
Many of my weight loss clients ask me if they are permitted to snack if they get hungry in between meals. A recent study published in the American Journal of Clinical Nutrition examined the impact of snacking on total daily calories. In this investigation, 3,777 men and women from the National Health and Nutrition Examination Survey were studied. These subjects each filled out two 24-hour dietary recalls. In one of the recalls, the subject reported snacking in between meals. In the other, they did not. Total calories were compared between the two days.

On the days that the men snacked, they consumed an extra 239 calories. The women consumed an extra 219 calories on the day that they snacked. Added sugars and sodium were significantly higher on the days that included snacking. American Journal of Clinical Nutrition 2019;109:1145-53.

Take Home Message
I have never been a big fan of snacking for my weight loss clients. If you are eating 3 good, blood sugar stabilizing meals each day, there is really no need to snack. You should not be at all hungry in between meals. The additional calories that snacking adds can have a dramatic impact on body weight. The 200 plus extra calories found in this study would result in nearly two pounds gained each month. 

Eat three balanced meals that include a healthy source of fat, protein and low glycemic carb. You won’t be hungry in between meals and it will be much easier to lose weight.

New research on eggs and cardiovascular disease

Eggs are back in the news in a big way after a meta-analysis published in April in the Journal of the American Medical Association showed an increased risk of cardiovascular disease with only ½ egg consumed per day. Should this study lead us to alter our consumption of eggs? Let’s take a closer look.

The Article
The meta-analysis included 29,615 participants from 6 prospective U.S. cohorts that were followed for roughly 18 years (Reference 1). Each additional half egg consumed per day was associated with a 6% higher risk of cardiovascular disease and an 8% higher risk of mortality.

Limitations And Other Research
While this is definitely an interesting study and we must consider the findings, there are two reasons not to go completely overboard and swear off eggs completely.

#1: There are some methodological issues with this study. To start with, only a single measure of egg consumption was taken and then subjects were followed for 18 years. There is a really good chance that egg consumption changed during this time. Very few of us eat the same way for 18 consecutive years. This study did not account for changes in diet over the follow-up.

Another methodological issue is that the control of confounders was not ideal. A confounder is a variable that may impact risk of cardiovascular disease. To deal with a confounder, you measure it and then control for it in statistical models. Similar to egg consumption, confounders in this study were not updated, just a baseline measure was used. This leaves the door open for residual confounding. Further, certain confounders were left out of the models, including family history of cardiovascular disease, menopausal status and supplement use.

#2: Other studies that were better executed do not show an increased risk of cardiovascular disease with a high consumption of eggs. For example, in an analysis of the Nurses’ Health Study and the Health Professional Follow-up Study that included 117,933 men and women, no significant association was found between consumption of one egg per day and risk of heart disease or stroke (Reference 2). In this study, both egg consumption and confounders were repeatedly updated during the follow-up period. There was also a more complete control of confounders.

Another very large meta-analysis was conducted a few years back (Reference 3). This analysis included subjects taken from 22 cohorts with a follow-up of up to 20 years. When comparing subjects who consumed one or more eggs per day to subjects consuming less than 1 egg per week, there was no increased risk of heart disease, stroke or total cardiovascular disease.

Conclusions And Recommendations
While the results of this new study need to be considered, a lot of other well-designed research has shown that eggs are safe to consume. If you are otherwise healthy, a moderate consumption of eggs can be considered part of a healthy diet. Keep in mind that eggs are a really good source of protein, healthy fat, vitamins and minerals. The yolks are very much like a multivitamin pill.

If you have diabetes, talk to your doctor about how many eggs you should consume, as some research has shown an increased risk of cardiovascular disease with high egg consumption in diabetics.

1) Zhong VW, et al. Association of dietary cholesterol or egg consumption with incident cardiovascular disease and mortality. Journal of the American Medical Association 2019; 321:1081-95.

2) Hu FB, et al. A prospective study of egg consumption and risk of cardiovascular disease in men and women. Journal of the American Medical Association 1999; 281:1387-94.

3) Shin, et al. Egg consumption in relation to risk of cardiovascular disease and diabetes: A systematic review and meta-analysis. American Journal of Clinical Nutrition 2013; 98:146-59.