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Causes of overeating and the science behind them

Before and After BMI

December 12, 2016

Causes of overeating and the science behind them

Just about everyone has experienced the discomfort that comes with overeating. That’s particularly true around the holidays, which can be a minefield of foods that leave you feeling bloated and lethargic. To help avoid this unhealthy behavior, discover the causes of overeating and the science behind them.

Man overeating while sitting on couch

What are some causes of overeating?

External cues

Our bodies have evolved to survive food shortages by taking in lots of food when it’s available, so we’re very susceptible to external triggers even when we’re not hungry. That’s why even after dinner, a commercial showing a delicious-looking pizza or hamburger can easily entice us to keep eating.


If you put yourself on a diet that’s too restrictive or make yourself skip meals, you could be setting yourself up for overeating. When you feel starved, you’re apt to binge, eating too many calories and making poor food choices.

Drinking alcohol

It’s easy to go to a holiday party and indulge in a few drinks, but did you know those drinks can make you more likely to overeat? A Texas Tech University study found that alcohol makes women more sensitive to the smell of food, and two-thirds of the women in the study ate more at lunch after drinking alcohol.


Persistent stress can increase your body’s production of cortisol, a hormone that may increase your appetite. In addition, physical or emotional distress makes you more likely to eat foods that are high in fat, sugar or both, according to studies.

Man sleeping on couch after overeating

What happens when you overeat?

When you overeat, your body undergoes some immediate changes, including the following:

Your stomach and intestines tell your brain you’re full

When you eat too much, your stomach and intestines produce hormones that signal to your brain that you’re full. Another hormone, leptin, also kicks in, telling your brain that you’ve had enough to eat. If you’re eating too fast, however, you may not be giving your body a chance to register that you’re full.

You feel lethargic

It’s not just your imagination – your body really does tend to crave a nap after a big meal. That’s because your small intestine is telling your brain that you need to rest and digest the food. Your insulin levels may also rise in an effort to move excess sugar from your bloodstream, which can also make you tired. Sometimes, insulin may actually be too good at its job, removing too much sugar and leaving you with low blood sugar levels and a lethargic feeling.

You may have gas and heartburn

You may have excess gas as your body breaks down food into energy. In addition, you might feel pain and pressure and experience bloating and burping as your body tries to get rid of the extra gas. Overeating can also cause acid to travel from your stomach into your esophagus, which results in a burning feeling that you’ll want to relieve.

Lots of food to represent the causes of overeating

Can short-term overeating affect you in the long term?

Overeating has plenty of short-term effects, but if you engage in this behavior frequently – even for relatively short periods of time – this can have detrimental long-term effects. In one study, participants of normal weight who overate by consuming unhealthy foods for a month weighed more and had a higher percentage of body fat than the control group… even 2.5 years later.

For more information about overeating causes and effects, contact BMI of Texas.