If eating more fills you up too much, try drinking your calories. Milk, 100-percent fruit juice and homemade smoothies add calories between meals. Whiz up a high-calorie smoothie containing a whole banana, frozen yogurt, milk, juice and nut butter or flax seed in your own kitchen. Include dried milk powder or protein powder to boost the calorie count of plain milk.
Avoid drinking copious amounts of beverages with meals, though.The liquid creates temporary feelings
of fullness in your stomach so you may eat less solid, calorie-containing food. Save drinks for before, after and between meals.