When you are not losing weight fast enough, you’re probably eating too many carbohydrates. Always look at your carbohydrate intake first. If you are keeping your carbs at 10-20 grams per feeding, and you are not losing weight fast enough – then and only then, cut your calories more. Fastest weight loss is on 500-600 calories a day, which is almost impossible to do without medication. Most patients stay pretty easily on 1000-1500 calories a day, and lose 3-5 pounds every week. If you’re not losing weight fast enough, the bet is you are eating too many carbohydrates.