Biochemistry and sleep. In addition overeating also helps you asleep. The Food Making You Tired Why Everyday Favourites Including Yoghurt Orange Juice And Sandwiches Are Depleting Your Energy Daily Mail Online Tryptophan is converted by the body to serotonin and then to melatonin and as noted above this can enhance sleepiness. Why does food make you sleepy . Jo eats white bread toast and strawberry jam for breakfast before going to work. During Thanksgiving Tryptophan in Turkey and over-eating are credited to falling asleep. In other words its completely normal. Poor food choices can make us fatigued drowsy and irritable. They increase the serotonin levels in the body which tends to. The stomach takes between two to three hours to digest food. Carbohydrates help the body absorb tryptophan. Overeating Chicken Curry or Lamb curry will make you fall asleep. An amino acid called tryptophan which occurs in many protein-rich foods helps the body produce serotonin.