Dietas de muchas calorias ayudan mas a bajar de peso

NEW YORK (Reuters Health) - Under medical supervision, a high-protein, low-carbohydrate diet is a safe and effective way for severely obese teenagers to lose weight, according to a new study.

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Effective treatment options for young people who are obese are limited, "particularly for those who are severely obese," Dr. Nancy F. Krebs, professor of pediatrics and head of the division of pediatric nutrition at the University of Colorado Denver School of Medicine and colleagues note in a report in The Journal of Pediatrics.

Doctors have been concerned about the safety of the high-protein, low-carbohydrate diet in children. "There have been fears that the diet could adversely impact growth and could increase cholesterol levels because it is a high-fat diet," Krebs explained in a telephone interview with Reuters Health. "This has been a barrier to it being used."

To investigate, the researchers randomly assigned 24 severely obese teenagers to eat a high-protein, low-carbohydrate diet and 22 matched teens to eat a low-fat diet for 13 weeks. The study subjects were 14 years old on average and were at least 175 percent above ideal weight, but were free of type 2 diabetes or other serious medical problems. They were closely supervised throughout the study.

On average, those on the high-protein, low-carb diet lost 29 pounds over 13 weeks, while those on the low-fat diet lost 16 pounds. Both groups kept the weight off nine months after the study. "We had expected the high-protein, low-carbohydrate group to quickly regain all the weight lost, but this did not occur," Krebs said. "At the end of the day, this suggests that with ongoing support, these patients could perhaps have achieved even more weight loss."

The high-fat, low-carbohydrate diet also appeared to be safe, with no serious harmful effects on growth, bone mineral density, and various "metabolic" parameters, such as cholesterol levels. Both groups showed declines in levels of harmful LDL cholesterol and increases in levels of heart-healthy HDL cholesterol.

Clinical psychologist Angela Celio Doyle of the University of Chicago's eating and weight disorders program, who was not involved in the study, said the study helps "fill the hole" in the scientific literature on adolescent obesity.

Doyle said the Colorado study supports the high-protein, low-carbohydrate diet as another option for severely obese teens to lose weight. "There really isn't any gold standard now for how to help these adolescents lose weight," she said.

The study received funding from the National Institutes of Health and the National Cattlemen's Beef Association.

SOURCE: The Journal of Pediatrics, published online March 22, 2010.