A 1000 calorie a day diet works better, faster and more efficiently when it’s very low in carbohydrate. Very low in carbohydrate means no more than 10-20 grams of carbohydrate per feeding. When it’s been studied, weight loss can be twice as rapid on 1500 calories of protein and fat a day, compared to 1500 calories of carbohydrate a day. You don’t have to restrict carbohydrates in order to lose weight, but you’ll be less hungry, you’ll have fewer cravings and you’ll have more energy if you do. Restricting carbohydrate also makes fat storate less efficient, so you lose weight faster too. All weight loss diets are relatively speaking low carbohydrate diets, because you are eating fewer carbohydrates than before you went on a diet. But efficient weight loss diets are very low carbohydrate.