Every calorie app tells you what you ate. Fuel Shift shows you what your body may be doing with it right now. See your energy across blood glucose, liver glycogen, muscle glycogen, and body fat, then watch your fuel stores rise, fall, and shift in real time. Log food and workouts normally. Fuel Shift simulates what happens next, shows what fuel mix you’re using, and lets you preview how a meal could change your timeline before you eat it.