Are we still spending time trying to prove/disprove the low fat effect? Apparently so. Lancet has just published another meta-analysis looking at randomized controlled trials, funded by NIH and the American Diabetes Association. Not surprisingly, low fat didn’t work when compared to low carbohydrate interventions. Low fat also lead to NO DIFFERENCE when compared to SAD…. Maybe a meta-analysis of long term low fat eaters is in order- I’d be most curious as to the squelae associated with such a choice….
3517 citations were identified by the search and 53 studies met our inclusion criteria, including 68 128 participants (69 comparisons). In weight loss trials, low-carbohydrate interventions led to significantly greater weight loss than did low-fat interventions (18 comparisons; WMD 1·15 kg [95% CI 0·52 to 1·79]; I2=10%). Low-fat interventions did not lead to differences in weight change compared with other higher-fat weight loss interventions (19 comparisons; WMD 0·36 kg [−0·66 to 1·37; I2=82%), and led to a greater weight decrease only when compared with a usual diet (eight comparisons; −5·41 kg [−7·29 to −3·54]; I2=68%). Similarly, results of non-weight-loss trials and weight maintenance trials, for which no low-carbohydrate comparisons were made, showed that low-fat versus higher-fat interventions have a similar effect on weight loss, and that low-fat interventions led to greater weight loss only when compared with usual diet. In weight loss trials, higher-fat weight loss interventions led to significantly greater weight loss than low-fat interventions when groups differed by more than 5% of calories obtained from fat at follow-up (18 comparisons; WMD 1·04 kg [95% CI 0·06 to 2·03]; I2=78%), and when the difference in serum triglycerides between the two interventions at follow-up was at least 0·06 mmol/L (17 comparisons; 1·38 kg [0·50 to 2·25]; I2=62%).