Research

Energy balance

A low-carbohydrate, high-protein, high-fat diet produces greater short-term weight loss (up to 6 months) than a conventional low-calorie, high-carbohydrate diet, but this advantage disappears by 12 months.

If you switch to a low-carb diet, expect faster weight loss in the first 6 months compared to a standard low-fat diet, but don't assume it will stay superior after a year. The initial boost likely comes from reduced calorie intake rather than a magical metabolic shift. To maintain results long-term, you likely need more than just a diet book; consider adding structured support or behavioral strategies to prevent the common drop-off seen in self-directed diets.

GoodQualifiesHIGH confidence
The low-carbohydrate diet produced a greater weight loss (absolute difference, approximately 4 percent) than did the conventional diet for the first six months, but the differences were not significant at one year.
Gary D. Foster et al. · New England Journal of Medicine · 2003

Why this rating

Randomized, controlled, multicenter trial with a relatively large sample size for its time, though limited by high attrition and short long-term follow-up.

Source

A Randomized Trial of a Low-Carbohydrate Diet for Obesity

Gary D. Foster et al. · New England Journal of Medicine · 2003

DOI 10.1056/nejmoa022207

rct · n=63Cited 1,791×
Read the paper
DOI resolved against Crossref · corpus check 2026-06-10

This is one finding among thousands. Every one is graded and traced to its source, so you can see what the evidence actually supports. Browse the research →