Low carb diets are believed to have positive effects for weight

Low carb diets are believed to have positive effects for weight loss, increased performance, management of diabetes, and even curing cancer.  In the JAMA article, low carb is compared to low fat diets in a 12 month trial.  Discuss the effectiveness of low carb diets in relation to: 1)   Weight changes between a healthy low-fat diet vs a healthy low-carbohydrate diet 2) Genotype pattern and baseline insulin secretion associated with the dietary effects on weight loss 3) Which diet was better for whom?