I bike to EAT, so I'm not the one to ask. My smoothie is not low-cal, but a recovery drink: 1 cup liquid (1% milk, oj, or apple juice), 1 banana (you can peel and freeze if you like your smoothies thicker), 1 cup frozen fruit (strawberry, blueberry, peach are my favorites). Optional: 1 scoop protein, 1 low-fat yogurt.