Consideration of calorie: 1 gm of carbohydrate provides approximately 4 kcal/gm calorie. On the other hand 1gm of fat provides 9.3 kcal/gm calorie. Therefore, low-fat diet will seemingly provide more calorie than low-carb diet.The studies comparing the effect of low-carb vs. low-fat diet: 1. Case:1 Study: 63 adults suffering from obesity followed either a low fat or a low carb diet for 12 months. Calorie was restricted in low fat diet group.