Thermodynamics at Work
The debate rages on in the diet industry about the best way to control weight. Fads come and go, but — this study argues — the key idea behind maintaining a healthy weight is basic and well-established: balance calories consumed against calories expended.
The findings are the latest in a string of studies to challenge claims that the secret to healthy weight loss lies in adjusting the amount of nutritional components of a diet — protein, fat and carbohydrates.
In the study, to be published in Wednesday’s issue of the Journal of the American Medical Association, 25 young, healthy men and women were deliberately fed nearly 1,000 excess calories a day for 56 days, but with diets that varied in the amounts of protein and fat.
While those on a low-protein diet — about 5% of total calories — gained less weight than those on a normal- or high-protein regimen, body fat among participants in all three groups increased by about the same amount. Typical protein consumption is about 15% of calories, while the U.S. government recommends it make up between 17% and 21% of total daily calories.
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The findings suggest that it matters little whether a diet is high or low in fat, carbohydrates or protein, it’s calories that build body fat.