High Protein Diet: Lose Weight, Without Losing Bone?

“Nutritional research today is typically the blind leading the blind. People following nutritional belief systems like religion,” explains Dr. Fuhrman and this study claiming that high protein diets help preserve bone integrity during weight-loss is no different. From the University of Illinois at Urbana-Champaign:

The scientists recruited and randomized 130 middle-aged, overweight persons at two sites—the U of I and Pennsylvania State University. Participants then followed either the higher-protein weight-loss diet or a conventional higher-carbohydrate weight-loss diet based on the food-guide pyramid for four months of active weight loss followed by eight months of weight maintenance.

"Essentially we substituted lean meats and low-fat milk, cheese, yogurt, etc., for some of the high-carbohydrate foods in the food-pyramid diet. Participants also ate five servings of vegetables and two to three servings of fruit each day," Evans said.

Bone mineral content and density were measured with DXA scans of the whole body, lumbar spine, and hip at the beginning of the study, at four months, at eight months, and at the end of the 12-month period.

"In the higher-protein group, bone density remained fairly stable, but bone health declined over time in the group that followed the conventional higher-carbohydrate diet. A statistically significant treatment effect favored the higher-protein diet group," said Matthew Thorpe, a medical scholars (MD/PhD) student who works in Evans's lab and was the primary author of the study.

I asked Dr. Fuhrman about this research and here’s what he had to say. Take a look:

There are so many variables that the conclusions are simplistic. First of all, the vast majority of Americans are severely Vitamin D deficient and their higher protein group was given more Vitamin D fortified milk. Second, the intervention group was encouraged to eat more green vegetables and less sugar, bread and white potato, getting higher level of bone building nutrients, including Vitamin K, and thirdly, the intervention group, though eating less refined carbohydrates were only given a diet a little higher in protein (30 percent) which is not a very high protein diet.

All in all, if they are going to claim some benefit to lean muscle or bone for the higher protein diet, they have to control for Vitamin D, K and other bone supportive nutrients that were higher in the intervention group. Even though this was a poorly designed and poorly controlled study, I basically agree with what they found—that a moderate protein diet with more fruits and vegetable and less refined foods bread and pasta, with attention to more Vitamin D from fortified skim milk will result in better bone mass with dieting compared to a diet not paying attention to these details. However, I think the better results stem from numerous factors, and not likely from a higher percentage of protein and less carbohydrate.

No doubt, this report will whip the low-carb congregation into their usual zealotry.

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Comments (2) Read through and enter the discussion with the form at the end
Chuck F - June 10, 2008 10:58 PM

Just Curious. Many of the ultra-extreme life-extension people now follow a high protein(30%) vegetarian diet, getting most of thier protien from sources such as rice protien concentrate/ whey protien sometimes Egg whites.

Based on my reading of this site, I still can't figure out if the authors problems with protien stem from the meat it's attached to or from the protien. Any Idea What Dr.Fuhrman thinks of the high protien vegetable diets?

Matt Thorpe - February 15, 2010 3:04 PM

Actually, a close reading of the report reveals the only nutrients not matched between groups were those found in dairy, lean meats and starchy staples - vegetable and fruit intakes did not differ between groups. Aside from protein and calcium, we found no differences in bone-building nutrients, including vitamin K. Both groups were prescribed and consumed similar levels of sugary and other 'junk' foods. In spite of the one additional serving of dairy daily, vitamin D intakes did not actually differ between groups.

In light of this, it is highly unlikely that any nutrients besides protein and potentially calcium explain the benefits. Other studies have shown that calcium supplements alone do not protect bone during weight loss. For these reasons, we stand by our conclusions that a diet rich in the combination of protein and calcium appear to have protected bone health during weight loss.

I concur with Chuck F above that the authors are very unclear about the scientific basis for their specific complaints. Most of the criticisms in this particular post are simply not correct.

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