What Occurs in Your Body When You Overeat
Immediate Effects of Overeating
- Acid reflux or heartburn
- Feeling sluggish
- Stomach discomfort
- Elevated blood sugar
When you eat, your stomach expands to hold what you have consumed. A stretched, or full, stomach sends signals to the brain that you are full. Eating too much can cause the stomach to stretch past its normal capacity, leading to feeling overly full. This can lead to pressure and discomfort as the contents of the stomach pass into the small intestine.
“In the short term, an extra large meal can cause digestive discomfort and possibly acid reflux, which can be very unpleasant,” says registered dietitian, Lauren Harris-Pincus, M.S., RDN, founder of NutritionStarringYOU.com and author of The Protein-Packed Breakfast Club. Acid reflux occurs when stomach acid flows back into the esophagus and causes a sour taste or burning sensation. “This is especially problematic when the meal is consumed close to bedtime because laying down will worsen the effects and interfere with sleep,” says Harris-Pincus.
Speaking of sleep, “Eating beyond your point of satisfaction can also cause a sense of drowsiness or feeling sluggish as the body is redirecting its attention to digesting the excess food,” says Harris-Pincus.
Your blood sugar can also become elevated, especially if you eat a large amount of carbohydrates, says Lauren Manaker, M.S., RDN, LD, a Charleston-based registered dietitian and owner of Nutrition Now. Blood sugar (glucose) rises after a meal, but refined carbohydrates spike blood sugar the most, compared to high-fiber carbs or carbs paired with protein and fat. When blood sugar rises, the pancreas releases the hormone insulin, which brings glucose from your blood to your cells for energy. Extra glucose is stored as glycogen in the liver and muscles. When the liver and muscles can’t store any more, the leftover glucose is stored as fat.
Long-Term Effects of Eating Too Much
- Weight gain
- Increased risk of Type 2 diabetes
- Insulin resistance
- Leptin resistance
- Elevated triglycerides
“Eating more calories than you expend will cause weight gain in the long term,” says Harris-Pincus. “It can also cause your blood sugar to spike, especially if the larger meals are heavy in processed carbohydrates and sugar.”
Overeating, even in the short term, can cause insulin resistance, in which cells are resistant to taking up the glucose that insulin is trying to deliver. According to a 2022 Journal of Eating Disorders study, binge eating high-fat and high-calorie foods results in elevated fasting blood sugar levels and increased insulin resistance. This, in turn, keeps blood sugar levels high and, over time, can lead to conditions like obesity and Type 2 diabetes.
Eating too much over time can also lead to leptin resistance, according to a 2019 Nutrients article. Leptin is a hormone produced by fat cells that tells the brain you are full. The more body fat someone has, the more leptin they will have. However, in leptin resistance, the brain doesn’t receive the signal from leptin to stop eating. Therefore, appetite remains high, leading to a vicious cycle of continuing to overeat, which can lead to more fat gain. Overeating can also raise triglyceride levels, especially if you consume too many high-sugar foods or drink too much alcohol.
Regarding your stomach, “One big meal like Thanksgiving won’t cause your stomach to ‘stretch’ [permanently] because it is meant to expand and contract to accommodate your daily food consumption,” Harris-Pincus says, but “consistently eating beyond when you are satisfied can cause your stomach to expand to handle the chronic extra food. This will require you to eat more food to become satisfied on a daily basis. The best way to avoid this is to listen to your body and its hunger and fullness signals to avoid overeating.”
