Layman: Low-Carb Diets Need Protein For Maximum Health Benefits

Dr. Layman's research focuses on the vital role of protein in the diet

Another one of America's best and brightest researchers in the field of low-carb research is nutrition professor Dr. Donald K. Layman. His work on the low-carbohydrate nutritional approach that you will hear about in my interview with him today is making a clear difference in the way people view diet and nutrition well into the future just as Dr. Eric Westman, Dr. Jeff Volek, and Dr. Richard Feinman already are as well, just to name a few.

Dr. Layman was kind enough to share a few moments with us today talking about his research on the low-carb approach as it relates to exercise and protein consumption. Prepare to be amazed by all the positive research that just keeps coming out about this miraculous way of eating.

1. Appearing at the "Livin' La Vida Low-Carb" blog today is yet another one of the behind-the-scenes people regarding the science behind low-carbohydrate diets. His name is Dr. Donald Layman from The University of Illinois at Urbana-Champaign. Dr. Layman, we are privileged and honored to have you with us today. Your studies into this incredible dietary approach that has helped so many people lose weight and get healthy is indeed fascinating. How and why did you become so interested in nutritional science?

My interest in nutrition has always focused on muscle development and physical activity. I have studied growth, sports nutrition and muscle wasting during starvation and malnutrition. It has been this work with skeletal muscle that got me interested in the optimum ratios of dietary protein and carbohydrates for life long health. Skeletal muscle needs protein to stay healthy.

2. It's probably not very glamorous doing studies about low-carb. Share with my readers just a little of what your daily work specifically entails.

I guess you’re correct that it’s not very glamorous, but I really enjoy the process of research. I enjoy the search for new ideas and I enjoy training students. My job description says that I spend 50% of my time on research and 50% on teaching.

I think what would surprise your readers is how long it takes to do good research. Even a relatively small study can take 3-4 years from initial concept and planning, through writing proposals for research funding, training research staff, conducting the experiments, frequently repeating experiments to prove reliability, evaluating data, preparing research papers and finally publishing the results. Good research takes a lot of time and often appears to move very slowly.

3. The primary focus of your research is on how changes in diet and exercise can help prevent the onset of health problems such as obesity, Type 2 diabetes, and metabolic syndrome, aka Syndrome X. Preventable disease is a growing problem not only in the United States but around the world now. Why do think people are so unwilling to make the necessary changes with what they eat and how much physical activity they get to keep themselves healthy? Who and/or what is to blame for these problems getting worse and worse?

I think there are lots of reasons people don’t (or can’t) change including time, knowledge, environment and motivation. The question about blame sounds too much like media hype. Why does someone have to be blamed?

As a society we now live longer healthier lives than any time in history. We have modern conveniences that save us time and effort and we have a wonderful food supply that provides us virtually any type of food at any time or during any season. Frankly, we are still learning how to handle our success.

We really do not know what diet is best for life spans that routinely reach into the 80’s and 90’s. But with that said, there is simply no question that we eat too much and exercise too little.

4. Your field of research has been focused on the role of exercise in preserving lean body mass, energy expenditure and maintaining weight. We often hear critics of the low-carb lifestyle talk about how you can't exercise on a low-carb program without "carb-loading." Is this true? If not, then please explain for us how the body functions and fuels itself during a workout for someone on a low-carb diet.

Carb-loading is definitely not required for exercise. Our muscles use two primary fuels, fats (or fatty acids) and carbs, specificially glucose. Think about exercise as a continuum from very low-intensity activity such as walking up to extreme- intensity exercise such as a world class 100-meter sprinter.

With very low-intensity walking the muscles should be using almost 100% fatty acids as the fuel, while the elite sprinter will be almost 100% glucose. Without carbs the sprinter will finish last, but without glucose the walker will simply burn more fats.

So for world class sprinters or marathon runners, carbs are an important fuel, but for the rest of us trying to maintain a healthy adult life, carbs do little more than prevent us from burning fats.

5. In fact, your research study published in the August 2005 issue of The Journal of Nutrition found that eating a low-carb/high-protein diet lead to increased fat-burning in the body as well as the creation of more muscle mass than those you observed on a low-protein, low-fat, high-carb diet. Although weight loss can still happen following a low-carb/high-protein nutritional approach, what are the health advantages of adding exercise to that routine?

I think the J. Nutrition paper was important because it demonstrated the interaction of dietary protein with exercise. The paper showed that the combination of a higher protein diet and exercise increased weight loss and targeted the weight loss to body fat while protecting lean tissues like muscles.

You’re right both diet groups lost weight and exercise helped both groups but there were differences in the amount of fat the was burned by each group.

For example, we had two groups that were diet-only treatment and two groups that were diet-plus-daily exercise. After 16 weeks of dieting, the group receiving the high-carb diet lost about 11 pounds of body fat, while the group consuming the low-carb, high-protein diet lost 13 pounds of body fat. The group that had the high-carb-diet-plus exercise lost 12 pound of body fat while the low-carb, high-protein diet plus exercise lost an amazing 19.5 pounds of fat!

So, the individuals eating a high-carb diet did 16 weeks of daily exercise and lost 1 pound of body fat more than just the diet effect, while the low-carb, high-protein subjects lost an additional 6.5 pounds of body fat doing the same exercise program. The higher protein diet maximizes the benefits of doing exercise.

6. A popular myth that floats around out there about livin' la vida low-carb is that your body hits a certain point during exercise when it stops burning fat for fuel and starts using lean muscle mass instead. Why do people believe they will lose muscle while on a low-carb diet and what really happens to muscle when people eat low-carb?

The answer to this question is a bit complex. This statement is derived from studies of long-term starvation. The body always needs some carbohydrates (glucose). The exact amount varies depending on specific conditions. During total starvation with no food being eaten, the body must rely on its own tissues to provide the essential mixture of fuels to sustain life.

The primary fuel is stored fat and fortunately (or unfortunately as the case may be) most of us could live at least 6 weeks without another meal. However, we also need a continuous supply of glucose. The body has a very small store of glycogen that can provide glucose for about 36 hours, then the body must make its glucose.

The body has three sources of glucose, one is the diet (but our person is starving), a second is glycogen (but this is all gone) and the third is a process called gluconeogenesis where the body makes glucose from amino acids. During starvation, the body must rely on body proteins for the amino acids. But under normal conditions, the body makes glucose from amino acids coming in from the diet.

This is one of the reasons that a low-carb diet must also be high-protein. The high-protein diet allows the body to make the necessary glucose from dietary amino acids and not rely on breaking down body proteins.

7. New research on protein and the effect it has on hunger has become the latest craze that food companies have attempted to take advantage of in the marketing of their foods over the past year. Your research looks closely at protein not just for satiety purposes, but also on the amino acids (especially leucine) it provides for other health benefits. What are some of theadditional reasons for eating more protein, how much should people be eating daily, and what are the best sources for protein that people can purchase?

Our research has shown that people lose more weight, they lose more body fat and less lean tissue, and they have more energy and feel less hungry when they consume protein. Specific mechanisms to explain each of these are not clear.

We think that the increase in the amino acid leucine along with the decrease in the levels of insulin produce the important changes in body composition. Mechanisms to explain the feelings of greater energy and reduced hunger are much more speculative.

The amount of protein that we use is approximately 110 to 130 grams each day with not less than 30 grams at each meal. We recommend use of dairy, meats and eggs as our primary sources of protein because they the right balance of amino acids and a high content of leucine.

8. Another one of those popular myths about people on a low-carb diet is that all of that meat they are eating will cause their kidneys to stop functioning and shut down. Why is this argument invalid and how can a low-protein diet be even more detrimental to someone's health?

That is simply not true. While special-interest groups continue to perpetuate this myth, the Food and Nutrition Board of the National Academies of Science reviewed this issue and they concluded that there was no evidence that diets high in protein harmed the kidney.

However, they did find that LOW protein diets resulted in reduced kidney function. So not only is the statement not true, the truth is exactly the opposite--low-protein diets are bad for your kidneys.

The origins of the myth is that individuals with advanced kidney failure need to reduce the work load on the kidneys which is done be reducing dietary intake of salts and protein. It is a totally different question to ask “what is the best way to treat a damaged kidney” versus “what is the best way to keep a healthy kidney healthy?”

9. Gout is a condition that low-carb diets seem to get blamed for as well. In your experience working with people following this way of eating, is this a problem that runs rampant?

We have now studied over 150 adults using high-protein, low-carb diets and we have never seen a single case of gout. Gout is not a problem with protein or amino acids, it is a metabolic problem associated with handling nucleotides which are the building blocks for DNA and RNA.

10. THANK YOU Dr. Layman for sharing your vast knowledge about the low-carb diet with me and my readers today. We are thankful to have someone like you bringing the real science behind low-carb to the forefront of our culture. Do you have any parting words you would like to share?

Never lose your passion for learning the truth.

We won't, Dr. Layman, we DEFINITELY won't! You can e-mail Dr. Donald K. Layman at dlayman@uiuc.edu.

10-27-06 UPDATE: One of my readers had a question about Dr. Layman's research.

What percentage of carbs, protein and fat did they eat? There are lots of studies coming out on low-carb diets but they never tell you how low the carbs are. This would be helpful information. Can you find out?

Well, I went back to Dr. Layman himself and here's what he said:

The carbs in our study diet were reduced but not super low. We required subjects to maintain diets with less than 170 total grams of carbs per day. Most of our subjects averaged about 140 total grams daily (including fiber). The type of carbs and the distribution throughout the day is as important as the absolute amount.

We use a ratio of carbs to protein in our teaching approach. At any meal or snack, the ratio of carbs to protein should be around 1 to 1. Since protein has such high satiety, this creates a self-limiting approach to carb intake.

THANK YOU for the question and hopefully Dr. Layman answered it for you to your satisfaction. Any other questions?