By Margarita Nahapetyan
Low-fat, low-carb or high-protein diet does not matter, all that really counts is to eat less and count your calories, according to a new federal study.
To come to this conclusion, the National Heart, Lung, and Blood Institute of the National Institutes of Health financed a study that involved hundreds of people with extra weight. The research was conducted by scientists at the Harvard School of Public Health in Boston and the Pennington Biomedical Research Center in Baton Rouge, part of the Louisiana State University system.
A team of researchers led by Dr. Frank M. Sacks designed a clinical trial that randomly assigned more than 800 overweight men and women with the ages between 30 and 70, to spend two years on one of four healthy diets with different combinations of fat, protein, and carbohydrates:
- A low-fat, average-protein diet
- A low-fat, high-protein diet
- A high-fat, average-protein diet
- A high-fat, high-protein diet
Protein in the diets ranged from 15 to 25 per cent of calories, fat from 20 to 40 per cent of calories, and carbohydrates from 35 to 65 per cent of calories. Each of the four diets used in the new study were low in saturated fat and cholesterol and high in dietary fiber which means they all were heart-healthy.
Each plan reduced about 750 calories from a participant's normal diet, but no one consumed less than 1,200 calories per day. Besides, all the participants were asked to exercise about an hour and a half every week, with acceptability of brisk walking, in addition to receiving group and individual diet counseling every eight weeks.
The results revealed that each of the eating plans worked the same way when measured by lost pounds. The 80 per cent of the participants who were on diets till the very end, lost an average of 13 pounds in the first six months. After two years, they had kept off an average of 9 pounds and lost 1 to 3 inches in the waist, regardless of which diet they were on. Dieters who had the best record of attending counseling sessions lost 22 pounds.
In addition, volunteers had improvements in heart-disease risk factors, including increases in the HDL (good) cholesterol by 9 per cent, and decreases in LDL (bad) cholesterol and triglycerides (blood fats), as well as blood pressure, at six months and two years. Participants reported similar levels of fullness, hunger and satisfaction on all four eating plans.
While the initial loss of 13 pounds may not seem like much, Sacks says it represents 7 per cent of the dieters' starting weight. The previous findings have shown that a weight loss between 5 to 10 per cent helps reduce the risk for developing heart disease and other conditions.
"What we found is that the most important thing for people to lose weight is to choose a heart-healthy diet and to keep the amounts down," concluded the scientist. "It is not so important whether they eat higher carbohydrates or higher protein or lower carbohydrates or lower protein," he said. "What really matters is just plain, simple old quantity: how much people eat."
The findings are published in the New England Journal of Medicine.