Because of its high soluble fiber content, chia seeds can absorb up to 10–12 times their weight in water, becoming gel-like and expanding in your stomach. Theoretically, this should increase fullness, slow absorption of your food and help you automatically eat fewer calories.  Fiber also acts as a prebiotic and feeds the friendly bacteria in your intestine.  Chia seeds are 40% fiber by weight, making them one of the best sources of fiber in the world.