Sleepy and tired after eating, with food in the stomach. When food is still present in the stomach and the person overeats, overeating produces a biochemical shock on the whole organism due to factors related to heavy breathing. Falling asleep and tired after eating (usually in 20-60 minutes after eating) are frequent signs of this biochemical shock. This effect of being sleepy after eating meals is much stronger after eating junk food and especially overeating (see the second half of this page for more info about this effect).