Two write-ups about the same large study.The good news is that there is no one diet that works - the key is to stick with the diet. From Science Daily:
In an analysis of data from nearly 50 trials including about 7,300 individuals, significant weight loss was observed with any low-carbohydrate or low-fat diet, with weight loss differences between diet programs small, findings that support the practice of recommending any diet that a patient will adhere to in order to lose weight.
Bradley C. Johnston, Ph.D., of the Hospital for Sick Children Research Institute, Toronto, and McMaster University, Hamilton, Ontario, and colleagues conducted a meta-analysis to assess the relative effectiveness of different popular diets in improving weight loss.
The meta-analysis included 59 articles that reported 48 randomized clinical trials (7,286 individuals; median age, 46 years; median weight, 207.5 lbs.). In the diet-class analysis adjusted for exercise and behavioral support, all treatments were superior to no diet at 6-month follow-up. Compared with no diet, low-carbohydrate diets had a median difference in weight loss of 19.2 lbs. and low-fat diets had similar estimated effects (17.6 lbs.).
At 12-month follow-up, the estimated average weight losses of all diet classes compared with no diet were approximately 2.2 to 4.4 lbs. less than after 6-month follow-up. The diet classes of low fat (16 lbs.) and low carbohydrate (16 lbs.) continued to have the largest estimated treatment effects.
Weight loss differences between individual diets were minimal. "Our findings should be reassuring to clinicians and the public that there is no need for a one-size-fits all approach to dieting because many different diets appear to offer considerable weight loss benefits.
From Medical Xpress:
At six month follow-up, people on low-carbohydrate diets lost 19 more pounds than those who were not on a diet, while those on low-fat diets lost 17 more pounds than those on no diet. After 12 months about two to three pounds of that difference was gone, and there was no difference between low-carbohydrate and low-fat diets.
Behavioural support in a diet made a difference at six months, enhancing weight loss by about seven pounds, while exercise was significant at 12 months, improving weight loss by about four and half pounds.