Is One Diet as Good as Another?
NOT!
Back at the beginning of the month, I commented on a recent study that’s been making the rounds, about how calorie intake – and not diet composition – is the main determinant of weight loss. In my opinion, this was kind of a “duuuuhhhh” sort of conclusion, as ALL successful diets work this way, whether calories are actually counted or not.
I did, however, add a caveat…diet composition CAN make a difference when it comes to body composition. The aforementioned study looked only at simple weight loss and didn’t discriminate between lean mass and fat losses. Yet, in my experience, WHAT is lost is as important (and perhaps even more important) as how much.
In support of this point, I brought up earlier work on higher protein diets by Donald Layman and colleagues, which was not cited by the study authors. This was a surprising omission, as Dr. Layman is a distinguished and prolific researcher. Thus, it comes as no surprise to me to see this press release on Dr. Layman’s latest study, which is hot off the presses:
URBANA – Any diet will do? Not if you want to lose fat instead of muscle. Not if you want to lower your triglyceride levels so you’ll be less likely to develop diabetes and heart disease. Not if you want to avoid cravings that tempt you to cheat on your diet. And not if you want to keep the weight off long-term.
“Our latest study shows you have a better chance of achieving all these goals if you follow a diet that is moderately high in protein,” said Donald Layman, a University of Illinois professor emeritus of nutrition. The research was published in the March Journal of Nutrition.
Layman’s new study followed the weight-loss efforts of 130 persons at two sites, the U of I and Penn State University, during 4 months of active weight loss and 8 months of maintenance. Two previous studies had looked at short-term weight loss; this one was designed to look at long-term effects, he said.
Although both plans were equal in calories, half the group followed a moderate-protein diet (40% carbohydrates, 30% protein, 30% fat) while the other followed a diet based on USDA’s food-guide pyramid (55% carbohydrates, 15% protein, 15% fat).
“Persons in the first group ate twice the amount of protein as the second group,” said Layman.
And the difference in protein made all the difference in improved body composition and body lipids, he said.
Although the amount of weight lost in both groups was similar, at 4 months participants in the protein group had lost 22 percent more body fat than members of the food-pyramid group. At 12 months, the moderate-protein dieters had lost 38 percent more body fat.
Same weight loss, but more of it was fat and less was muscle. Why is that important?
“The additional protein helped dieters preserve muscle. That’s important for long-term weight loss because muscle burns calories–if you lose muscle, and you used to be able to consume 2,000 calories without gaining weight, you’ll find that now you can only eat, say, 1,800 calories without weight gain,” he said.
The higher protein dieters also had greater improvements in serum triglycerides, and was equally effective at reducing LDL (“bad”) cholesterol.
The moral of the story? It’s that there’s more to a diet than simple weight loss. Diet composition and body composition are linked. Higher protein diets not only work, they work better than their lower protein, RDA-based counterparts.
