High-Protein, Low-Carb Diet Safe and Effective for Adolescents

At the end of 12 weeks, the teens on the high-protein, low-carbohydrate (HPLC) diet lost an average of 9.0 kg, while those on the low-fat diet lost an average of 5.6 kg, a significant difference, Dr. Nancy F. Krebs of the University of Colorado, Denver, said at a meeting on clinical pediatrics sponsored by the University of California, San Francisco.

Moreover, adolescents in both groups tended to maintain their weight loss over an additional 24 weeks of follow-up. “My hypothesis was that [the HPLC diet] would get them to 12 weeks but they’d rebound,” possibly even ending up heavier than before. 

In fact, while adolescents in the HPLC group tended to gain back a little weight within the first 3 months after the end of the diet, they still weighed less than those in the low-fat group. And the HPLC group appeared to maintain that difference for another three months, although those differences did not reach statistical significance.

All the adolescents in the study were severely overweight, weighing at least 175% of their ideal body weight. The teens in the HPLC group were placed on a diet limiting them to 20 g/day of carbohydrates. To ensure that they were compliant with this diet, the investigators measured ketone levels twice daily. People on HPLC diets tend to become ketonic quickly, something that can be measured easily with a urine dipstick.

In terms of body composition, both groups of adolescents lost equivalent amounts of fat and protein. In this study, the HPLC diet proved not to be protein sparing.

Both groups showed similar improvements in their lipid profiles, with one exception. Adolescents on the HPLC diet lowered their triglyceride levels significantly more than the low-fat group. 

Based on glucose tolerance test results, carbohydrate metabolism improved in both groups. The investigators observed no adverse effects of the HPLC diet.

“I have become a believer in this. I think it actually works for a number of kids quite well,” Dr. Krebs said. “I feel pretty comfortable in using it.”