100 calories per bar. Artificially flavored. The new Slim-Fast 3-2-1 Plan: Choose 3 snacks a day. 3 snacks, 2 meal bars or shakes plus 1 sensible meal. A simple daily plan to help you get results and lose weight now! A line of bars to satisfy your sweet cravings with 100 calories. Lose weight now. Pick 3 nourishing snacks a day (fruit, veggies or a snack bar); Choose 2 Slim-Fast 180-200 calorie shakes or meal bars; Have 1 sensible 500 calorie meal. Great tasting bars with 100 nourishing calories. Got an event coming up? Get started now.