According to American research, the most effective weight-loss diet for any person depends on his physiology.
Lead author David Ludwig, director of the Optimal Weight for Life Program at Children's Hospital Boston, who says that 'This study shows that one diet doesn't necessarily fit all', also notes that heavy people with an apple shape —carrying most of their weight in their midsection — lost a lot more pounds on a diet that excluded processed carbohydrates but included plenty of healthful fats. This was in comparison with people with a similar figure who were put on a low-fat diet.
The researchers put 73 adults, ages 18 to 35, on one of two diets. All participants were advised to eat the same amount of protein and fiber and to do the same amount of exercise.
Out of these, half were told to follow a low-fat diet that derived 55% of calories from carbohydrates, 20% from fat and 25% from protein. This diet encouraged low-fat, whole-grain products, vegetables, fruits and limited consumption of high-fat foods and sweets.
The other half followed a low-glycemic load diet — similar to traditional diets around the world, including the Mediterranean diet.
These dieters were allowed to eat a 'liberal amount of healthful (unsaturated) fats,' such as olive and canola oil, and encouraged to eat vegetables, fruits, whole grains, beans and nuts, he says.
These kinds of carbohydrates are considered low on the glycemic index scale, which ranks their effect on blood glucose levels. They are believed to stabilize blood sugar after a meal, lower the hormone insulin and stave off hunger longer.
The dieters also were advised to limit processed carbohydrates, such as white bread, white rice, prepared cereals, crackers, cookies and sugary foods. Research indicates that these foods, considered high on the glycemic index scale, sharply raise blood sugar and insulin levels, stimulating hunger and resulting in overeating.
Dieters on this plan got about 40% of calories from carbohydrates, 35% from fat and 25% from protein.
One of the biggest differences between the diets is that people on the low-glycemic-load plan were encouraged to moderately decrease carbohydrates and increase healthy oils, nuts and seeds, says co-author Cara Ebbeling of Children's Hospital.
The findings included that dieters who secreted the most insulin and tended to have an apple shape lost an average of 13 pounds on the low-glycemic-load diet in six months. They also kept all of that weight off at the end of 18 months by following the maintenance portion of the program.
Participants who secreted a lot of insulin but followed the low-fat plan lost 5 pounds in six months and kept off only 2.6 pounds at 18 months.
It was also seen that those who secreted lower amounts of insulin and tended to have a pear shape — heavier through the hips — lost equal amounts of weight on both diets. They dropped about 10 pounds in six months and regained about half of it at the end of 18 months.
Anthony Fabricatore of the University of Pennsylvania School of Medicine says: 'This new work raises the question of whether patients seeking weight loss should be screened for insulin response before a certain type of diet is recommended. Perhaps we can enhance weight loss outcomes by matching patient to diet, based on physiological characteristics.'
The study was published in the latest edition of the Journal of the American Medical Association.