A large study of multiple studies already published (a meta-analysis, one of the best ways to determine the validity of study results) shows that most diets result in similar weight loss, whether they are low-carbohydrate or low-fat or simply moderate overall diets. All diets were better than no diet in terms of weight loss.
This makes sense. Most diets result in more appropriate calorie intake and better nutrition. I do think that from a nutritional standpoint, some diets are better than others. The Mediterranean diet or a variation of it is what I think is best. Regardless, any diet is likely to result in weight loss. Dieting should be done carefully and wisely, with attention to nutrition. Physical activity should be part of any program for weight loss and overall improvement in health. Eating healthy, feeling healthy, a healthy lifestyle, and a positive attitude are more important than the number of pounds lost. Any diet that a patient finds easy to follow and feels good about is likely to succeed. There is no magic formula behind any particular diet.
Johnston BC, Kanters S, Bandayrel K, et al. Comparison of Weight Loss Among Named Diet Programs in Overweight and Obese Adults: A Meta-analysis. JAMA. 2014;312(9):923-933. doi:10.1001/jama.2014.10397
