Active Level Keto Two cups of water before each meal, weight loss 44% faster. That is why the so-called "negative calorie preload" is on my list of weight loss boosters, which are all the things I could find that can accelerate weight loss regardless of what I eat the rest of the time. Preloading negative calories only means starting a meal with foods that contain less than one hundred calories per cup. That includes many fruits, vegetables, soups, salads or just a tall glass of water.