Jeff Volek on USDA Food Guidelines

Here's the nugget from Dr. Volek's comments:

"4th Point – In respect to low carbohydrate diets posing a health risk, many research teams have repeatedly shown that low carbohydrate diets are more likely than low fat diets to effect global improvement in insulin resistance. Insulin resistance, metabolic syndrome, pre-diabetes, diabetes, and many forms of obesity are all manifestations of carbohydrate intolerance. Therefore carbohydrate restriction is a fully rational approach for these people. Considering that 2 in 3 are overweight and a majority of those people likely have some degree of insulin resistance, we are conservatively talking about several million people who stand to benefit from a diet less than 45% carbohydrate. The markers that show the most consistent improvement in response to a low carbohydrate diet are plasma glucose, insulin, triglycerides, HDL cholesterol, LDL particle size, inflammatory markers, and vascular function. Since low carbohydrate diets bias metabolism to burning fat, saturated fat levels in the body actually decrease on a low carbohydrate diet."

My Comments on DGAC Report on Proposed 2010 USDA Dietary Guidelines

by Jeff Volek, Ph.D., Nutrition and Metabolism Society

My comments pertain to Safety and Effectiveness of Low Carbohydrate Diets.  To establish credibility on this topic since there seems to be no shortage of experts in nutrition, I’m a PhD-trained researcher and registered dietitian, and I have conducted a large amount research on low carbohydrate diets including author/co-author of 23 peer-reviewed scientific manuscripts examining how humans adapt to low carbohydrate diets, 7 studies in animals, and 14 review papers.

The key statement in the DGAC Report is:

“Diets that are less than 45% carbohydrate or more than 35% protein are difficult to adhere to, are not more effective than other calorie-controlled diets for weight loss and weight maintenance, and may pose health risk, and are therefore not recommended for weight loss or maintenance.”

In other words the DGAC report is telling ALL Americans to consume at least 45% of their calories as carbohydrate, and there is no benefit of consuming less than this amount.

1st Point – “Diets less than 45% carbohydrate are difficult to adhere to.”  is not accurate.  Reported rates of attrition in studies comparing low carbohydrate diets to low fat diets show similar if not better adherence to diets lower in carbohydrate. It also seems at odds with the millions of adults currently following a low carbohydrate diet. Even if this premise is accepted, just because a diet might be ‘difficult to adhere to’, does not mean we should abandon ship. It’s also difficult to quit smoking, but that does not dissuade us from promoting smoking cessation.

2nd Point – On the issue of not recommending diets greater than 35% protein, I agree with this position. But the report often incorrectly uses the terms low carbohydrate and high protein interchangeably. Sustainable low carbohydrate diets contain adequate but not excessive protein.

3rd Point – On the issue of low carbohydrate diets “not being more effective than other calorie-controlled diets for weight loss and weight maintenance”…In all comparisons of any duration, low carbohydrate diets do at least as well and sometimes better than control low fat diets. A major limitation in long-term studies is compliance, and after 6-12 months diet groups are usually consuming something that resembles their habitual diet and so it is not surprising weight loss/maintenance is similar.

4th Point – In respect to low carbohydrate diets posing a health risk, many research teams have repeatedly shown that low carbohydrate diets are more likely than low fat diets to effect global improvement in insulin resistance. Insulin resistance, metabolic syndrome, pre-diabetes, diabetes, and many forms of obesity are all manifestations of carbohydrate intolerance. Therefore carbohydrate restriction is a fully rational approach for these people. Considering that 2 in 3 are overweight and a majority of those people likely have some degree of insulin resistance, we are conservatively talking about several million people who stand to benefit from a diet less than 45% carbohydrate. The markers that show the most consistent improvement in response to a low carbohydrate diet are plasma glucose, insulin, triglycerides, HDL cholesterol, LDL particle size, inflammatory markers, and vascular function. Since low carbohydrate diets bias metabolism to burning fat, saturated fat levels in the body actually decrease on a low carbohydrate diet.

In summary, the one-size-fits-all approach that encouraged people to eat less fat and consume complex carbohydrates has been unsuccessful for many (if not the majority) of us.  The recommendation to consume roughly half the calories from carbohydrate is problematic for the growing number of people with obesity and underlying insulin resistance. I strongly encourage USDA to support a lower range of carbohydrate which will help many people better manage their obesity and insulin resistance.

Jeff Volek is a research scientist and Associate Professor at the University of Connecticutt Neag School of Education. He holds a Ph.D. in Kinesiology, an M.S. in Exercise Scientce, He is an R.D. and has a B.S. in Dietetics. He is a member of the Nutrition and Metabolism Societyand serves on their Scientific Board.

His primary area of research is focused on physiological adaptations to low carbohydrate diets with emphasis on outcomes related to metabolic syndrome, diabetes, and cardiovascular disease. He primarily uses prospective diet and/or exercise interventions and sophisticated cellular techniques to understand changes in adiposity, fatty acid and lipoprotein metabolism, inflammation, vascular function, and endocrine adaptations. His recent studies have suggested a shift in understanding the role of dietary carbohydrate restriction. Long considered primarily a stratagem for weight loss, reduction in dietary carbohydrate is now understood to lead to improvements in metabolic syndrome and other cardiac risk factors, even in the absence of weight loss and frequently even in the presence of higher levels of saturated fat. Another major area of research has been in the general area of sports nutrition, including studies evaluating a wide range of dietary supplements on exercise performance and overall health.

http://hartkeisonline.com/2010/07/21/usda-low-fat-high-carb-plan-doesnt-work-for-many-says-nutrition-scientist/