Change in proportional protein intake in a 10-week energy-restricted low- or high-fat diet, in relation to changes in body size and metabolic factors.
Study Goal
The researchers aimed to compare the effects of low-fat and high-fat diets under energy restriction, focusing on changes in protein intake and their impact on body size and metabolic factors.
Results Summary
The low-fat diet group with increased protein intake showed greater weight loss and cholesterol reduction compared to the high-fat group with decreased protein intake. The high-fat diet reduced triglycerides more than the low-fat diet, but this effect was matched by the low-fat group with increased protein intake.
Population
Obese adults (n = 771, with 585 completers).
Effective Dosage
600 kcal energy-deficient diets (low-fat: 20-25% fat; high-fat: 40-45% fat).
Duration
10 weeks.
Interactions
None mentioned.
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
low-fat diet with >2 prot% increase | decrease | weight | obese adults | 1.1 kg more | lost more weight | #1 |
low-fat diet with >2 prot% increase | decrease | cholesterol | obese adults | 0.25 mmol/l more | reduced cholesterol more | #2 |
low-fat diet with >2 prot% increase | decrease | weight | participants on a low-fat diet who had increased the percentage energy intake from protein | - | showed the greatest reduction | #3 |
low-fat diet with >2 prot% increase | decrease | cholesterol | participants on a low-fat diet who had increased the percentage energy intake from protein | - | showed the greatest reduction | #4 |
high-fat diet | decrease | plasma triglycerides | obese adults | - | reduced plasma triglycerides more | #5 |
low-fat diet with >2 prot% increase | decrease | triglycerides | participants on a low-fat diet who had increased the percentage energy intake from protein | - | showed a triglyceride reduction equally large | #6 |
OBJECTIVE: To investigate in a secondary analysis of a randomised trial the effects of a low-/high-fat diet and reported change from baseline in energy% from protein (prot%), in relation to changes in body size and metabolic factors. METHODS: Obese adults (n = 771) were randomised to a 600 kcal energy-deficient low-fat (20-25 fat%) or high-fat (40-45 fat%) diet over 10 weeks. Dietary intake data at baseline and during the intervention were available in 585 completers. We used linear regression to calculate the combined effects of randomised group and groups of prot% change (<-2 /-2 to 2/>2) on outcomes. RESULTS: The low-fat group with >2 prot% increase lost 1.1 kg more weight (p = 0.03) and reduced cholesterol by 0.25 mmol/l more (p = 0.003) than the high-fat group with >2 prot% decrease. These differences were 2.5-fold and 1.8-fold greater than the differences between the low-fat and high-fat groups while not considering prot% change. The high-fat group reduced plasma triglycerides more than the low-fat group, but not compared to those in the low-fat group with >2 units prot% increase (p fat-protein interaction = 0.01). CONCLUSIONS: Under energy restriction, participants on a low-fat diet who had increased the percentage energy intake from protein showed the greatest reduction in weight and cholesterol, and a triglyceride reduction equally large to that of participants on a high-fat diet.