According to Clifton, carbohydrate-restricted diet influenced weight loss, but if not combined with protein, then there is also a loss of lean body muscle mass. Clifton mentioned that a protein intake of more than 1.05g/kg of body weight increased retention of lean body muscle mass.
Clifton described low-glycemic index diets as inclusion of all complex carbohydrates with no simple sugars, similar to a diabetic diet. According to this author, low-glycemic-index and low-glycemic load diets lead to both weight loss and the lowering of LDL cholesterol.
According to Anderson JW et al, a very low calorie diet refers to an intake less than 1000 kcal per day. The difference in weight loss between this diet and a low-calorie diet of about 1100-1600 kcal per day becomes small in the long term. Also, those subjects who exercised maintained the weight loss longer. (52)