We’ve all experienced it: you finish a heavy lunch and suddenly your eyelids feel heavy. That post-meal drowsiness has a scientific name - postprandial somnolence, also colloquially called a “food coma.” 

Several mechanisms combine to create that sleepy sensation:

• Hormone shifts and brain chemistry: After you eat, levels of serotonin and melatonin can rise, promoting relaxation and sleepiness.

• Blood sugar spikes and crashes: Meals heavy in refined carbs raise blood glucose quickly, followed by a dip. That drop can leave you feeling tired. 

• Digestive load and metabolic demand: Large meals require a lot of energy to digest. The body diverts effort toward digestion, which can reduce mental alertness. 

• Meal composition matters: Foods high in fat, carbohydrates, or the amino acid tryptophan tend to intensify the effect. 

• Natural circadian dip: We naturally experience a low in alertness during mid-afternoon. Eat heavy during that window, and the effect is magnified. 

In most cases, a bit of post-meal drowsiness is normal and harmless. But if it’s extreme, persistent, or accompanied by other symptoms (e.g. excessive fatigue, dizziness, blood sugar issues), it’s wise to consult a doctor: conditions like diabetes, thyroid imbalance, or food intolerances may contribute. 

To reduce the “food coma,” try these strategies:

• Eat smaller, balanced meals with protein, fiber, and healthy fats. 

• Stay hydrated and avoid alcohol at meals. 

• Take a light walk after eating - movement helps stimulate alertness.

• Time your meals away from your body’s natural low in alertness (mid-afternoon). 

Understanding why we feel sleepy after overeating helps us balance enjoyment and functionality - so you can eat well and stay sharp.