Whether you’re at home or out and about, endless tasty food options and the wide availability of quick snacks make it easy to overeat.

If you’re unaware of portion sizes, overeating can easily spiral out of control and lead to various negative health consequences.

One way to get this habit under control is to first understand how overeating affects your body.

Here are 7 harmful effects of overeating.

Your daily calorie balance is determined by how many calories you consume versus how many you burn.

When you eat more than you expend, this is known as a calorie surplus. Your body may store these additional calories as fat.

Overeating may be especially problematic for developing excess body fat or obesity because you may be consuming far more calories than you need (1).

That said, overconsuming protein doesn’t likely increase body fat due to the way it’s metabolized. Excess calories from carbs and fats are much more prone to boost body fat (1, 2).

To prevent excess fat gain, try filling up on lean proteins and non-starchy vegetables before eating higher carb and higher fat foods.

SUmmary

Overeating is closely linked to excess body fat and obesity due to your body being in a calorie surplus. To avoid fat gain, focus on lean proteins and non-starchy vegetables at meals.

Two major hormones affect hunger regulation — ghrelin, which stimulates appetite, and leptin, which suppresses appetite (3).

When you haven’t eaten for a while, ghrelin levels increase. Then, after you’ve eaten, leptin levels tell your body that it’s full.

However, overeating may disrupt this balance.

Eating foods high in fat, salt, or sugar releases feel-good hormones like dopamine, which activate pleasure centers in your brain (4).

Over time, your body may associate these pleasure sensations with certain foods, which tend to be high in fat and calories. This process may eventually override hunger regulation, encouraging you to eat for pleasure rather than hunger (5).

Disruption of these hormones may trigger a perpetual cycle of overeating.

You can counteract this effect by portioning out certain feel-good foods and eating them at a slower pace to allow your body to register its fullness.

Summary

Chronic overeating may override hormones that control fullness and hunger, making it difficult to determine when your body needs food.

While occasional overeating likely doesn’t affect long-term health, chronic overeating can lead to obesity. In turn, this condition has consistently been shown to increase disease risk (6, 7, 8).

Obesity, which is defined as having a body mass index (BMI) of 30 or above, is one of the main risk factors for metabolic syndrome. This cluster of conditions raises your chances of heart disease and other health problems, such as diabetes and stroke (9).

Indicators of metabolic syndrome include high levels of fat in your blood, elevated blood pressure, insulin resistance, and inflammation (9).

Insulin resistance itself is closely linked to chronic overeating. It develops when excess sugar in your blood reduces the ability of the hormone insulin to store blood sugar in your cells.

If left uncontrolled, insulin resistance may lead to type 2 diabetes.

You can reduce your risk of these conditions by avoiding high calorie, processed foods, eating plenty of fiber-rich vegetables, and moderating portions sizes of carbs.

summary

Chronic overeating may promote obesity and insulin resistance, two major risk factors for metabolic syndrome — a cluster of conditions that increases your risk of heart disease, stroke, and diabetes.

Over time, overeating may harm brain function.

Several studies tie continual overeating and obesity to mental decline in older adults, compared with those who do not overeat (10, 11, 12).

One study in older adults found that being overweight negatively affected memory, compared with normal weight individuals (11).

That said, more studies are needed to identify the extent and mechanisms of mental decline related to overeating and obesity.

Given that your brain comprises approximately 60% fat, eating healthy fats like avocados, nut butters, fatty fish, and olive oil may help prevent mental decline (12, 13, 14).

Summary

Chronic overeating and obesity are linked to slight cognitive decline with aging, though further research is necessary.

Overeating on a regular basis can cause uncomfortable feelings of nausea and indigestion.

The adult stomach is approximately the size of a clenched fist and can hold about 2.5 ounces (75 mL) when empty, though it can expand to hold around 1 quart (950 mL) (15, 16).

Note that these numbers vary based on your size and how much you regularly eat.

When you eat a big meal and start to reach the upper limit of your stomach’s capacity, you may experience nausea or indigestion. In severe cases, this nausea may trigger vomiting, which is your body’s way of relieving acute stomach pressure (17).

While numerous over-the-counter medications may treat these conditions, the best approach is to regulate your portion sizes and eat slower to prevent these symptoms in the first place.

Summary

Acute overeating can lead to nausea and indigestion due to large volumes of food entering your stomach and hampering your digestive system.

Eating large amounts of food may strain your digestive system, triggering gas and bloating.

The gas-producing items that people tend to overeat are spicy and fatty foods, as well as carbonated drinks like soda. Beans, certain veggies, and whole grains may also produce gas, though these aren’t overeaten as often.

Furthermore, eating too fast may promote gas and bloating due to large amounts of food rapidly entering your stomach (18, 19).

You can avoid excess gas and bloating by eating slowly, waiting until after meals to drink fluids, and reducing your portion sizes of gassy foods.

summary

Eating large amounts of spicy and fatty foods, as well as drinking fizzy beverages like soda, can cause gas and bloating.

After overeating, many people become sluggish or tired.

This may be due to a phenomenon called reactive hypoglycemia, in which your blood sugars drop shortly after eating a big meal (20, 21, 22).

Low blood sugar is commonly associated with symptoms like sleepiness, sluggishness, rapid heart rate, and headaches (23).

While not fully understood, the cause is thought to be related to excess insulin production (24).

Though most common in people with diabetes who administer too much insulin, reactive hypoglycemia may occur in some individuals as a result of overeating.

summary

Overeating may cause some people to feel sleepy or sluggish. This may be due to excess insulin production, which leads to low blood sugar.

It’s easy to overeat if you don’t pay attention to how much you eat or how full you feel.

Indeed, this common habit may lead to bloating, gas, nausea, excess body fat, and a higher risk of several illnesses.

Therefore, you should work to prevent overeating by reducing your portion sizes, eating fewer processed foods, and orienting your diet around whole foods.

If you desire, you can consult a dietitian to help you create an eating plan that promotes long-term health.