Is weight loss more effective from a high fat, high protein or high carbohydrate diet?

From: NEJM

Journal rating:
rating: 100%
Study Quality:
rating: 85%

Overall Reliability

Article Quality:
rating: 75%
rating: 25%


  • 811 overweight adults


  • Participants were randomly assigned to one of four diets;
  • 20% fat, 15% protein, and 65% carbohydrates (low- fat, average-protein); 20% fat, 25% protein, and 55% carbohydrates (low-fat, high-protein); 40% fat, 15% protein, and 45% carbohydrates (high-fat, average-protein); and 40% fat, 25% protein, and 35% carbohydrates (high-fat, high-protein).
  • The participants were offered group and individual instructional sessions for 2 years.


  • At 6 months, participants assigned to each diet had lost an average of 6 kg, which represented 7% of their initial weight.
  • Participants began to regain weight after 12 months.
  • Among the 80% of participants who completed the trial, the average weight loss was 4 kg; 14 to 15% of the participants had a reduction of at least 10% of their initial body weight.
  • Satiety, hunger, satisfaction with the diet, and attendance at group sessions were similar for all diets; attendance was strongly associated with weight loss (0.2 kg per session attended).


  • No (without confidence) - the diets were equally successful in promoting clinically meaningful weight loss.


Editors Notes

  • Most of the weight loss occurred in the first 6 months.
  • Despite the results being clinically meaningful, the results are not statistically significant.
  • Possible conflict of interest exists