What Science Says About Overeating

image of unhealthy burger and fries. Fast food is a major cause of overeating.

Overeating isn’t the only reason people become overweight or obese but it’s a contributing factor for many people. How many times have you sat down to enjoy a meal and indulged a little more than you planned on?

Chances are the foods you ate seconds or thirds of wasn’t broccoli or greens beans but foods that spark the feel-good chemicals in your brain, like pizza or a creamy dessert. Sometimes we even overeat without being aware of. Have you ever dined at a restaurant with friends and mindlessly nibbled on bread from the bread basket? You may have been surprised, and a bit dismayed to discover that by the end of the meal you’d eaten several pieces.

It would be nice if there were a simple reason why we overeat, but it’s rarely that simple. Scientists break down the forces that cause us to eat into two types: internal and external cues. Both can get out of whack and cause us to eat more than we should.

Overeating: Internal Cues

Internal cues are those that come from inside your body. These are hunger cues activated by a low energy state and are mediated by appetite hormones. There are a number of hormones that impact appetite with leptin and ghrelin being the two bigger players. Ghrelin increases the desire to eat while leptin when it works properly, reduces appetite. However, some obese people are resistant to leptin’s signals and feel hungry even when they have plenty of circulating leptin and their energy stores are sufficient.

Another type of cue that comes from within is the sense of reward we get when we eat something delicious. Food, particularly sugary or fatty foods, activates reward centers in the brain that make us feel good. Therefore, we learn to associate that food with pleasure. In some ways, tasty foods behave similarly to an anti-depressant by altering brain activity and the level of neurotransmitters like dopamine and serotonin. Another problem is internal feelings like stress and anxiety that cause overeating as a way to activate the “feel good” reward centers that soothe stress.

Internal cues cause overeating when they trigger hunger inappropriately or we misinterpret those cues. While you may not think you have control over internal cues, you’re more in the driver’s seat than you think. We know that factors, like not sleeping enough and not managing stress, can bring on the desire to eat even when energy supplies aren’t low. That’s why it’s important to manage stress in a way that doesn’t involve food. A practice like yoga or meditation not only eases nervous tension and worry but makes you more mindful of how and what you’re eating. It goes without saying that you should get seven or more hours of sleep night as lack of sleep activates the appetite hormone ghrelin.

Overeating: Internal CuesExternal Cues

Many people also fight a battle with external cues that trigger overeating. External cues are those that come from the environment around us – and there’s a multitude of them. If you haven’t noticed, we’re constantly bombarded with images and messages about food from fast food ads to junk food aisles at grocery stores. To grab more attention, fast food signs are often designed with bright colors that excite your senses and stimulate your appetite.

If you eat out at a restaurant, the waiter or waitress will likely bring you a plate of food with portion sizes that are several times greater than what a standard portion should be – and that’s after they bring a bread basket. Then, they’ll tempt you with a dessert menu. Somewhere in the back of your mind, you remember mom’s message not to waste food so you dutifully clean your plate – and you end up getting more than you bargained for. A large meal at a restaurant may contain more calories than one person needs in a day!

The aroma of food can grab you too. The sensory aspects of food are sometimes referred to as hedonic characteristics as they increase the desire to eat in the absence of true hunger. Studies show that people who are overweight or obese are more sensitive to external and hedonic signals that spark overeating.

How can you address these external cues that cause you to overeat even when you don’t need the fuel? Make sure you control the environment around you. You have control over what’s in your kitchen. Purge your living environment of junk food and replace it with nutrient-dense whole foods. These foods supply your body with the micronutrients they need while not over stimulating the reward centers in your brain so that you want to keep eating. Consume more protein, the most satiating of the macronutrients. Clean up and organize your kitchen. Studies show that a cluttered, disorganized kitchen creates enough stress to cause you to overeat.

At work, don’t venture into the break room where there’s an assortment of food-related items to snack on. Chances are, the food on display isn’t nutrient-dense, whole foods. When you eat a meal or snack, take a mindful approach. Focus on what you’re eating, stop and put down your fork between bites, and only make enough for a single serving, so you won’t grab seconds or thirds. Also, don’t multitask when you eat. Anything that distracts you from the task at hand, eating, can cause you to eat more than you intended.

The Bottom Line

Being more aware of your body’s internal and external cues and knowing when hunger is real and when it’s just hedonic can help you curb the overeating habit. Question the cues that are telling you to eat. Is it truly hunger or is it boredom or stress? By simply becoming aware of your internal cues and modifying your external ones, you can make smarter decisions about when, how much, and what to eat.



Psychology Today. “Hunger Comes From Your Mind, Not Just Your Stomach”
Medical Daily. “A Messy Kitchen Induces Sense of Chaos, Prompts Overeating”
J Sleep Res. 2008 Sep;17(3):331-4. doi: 10.1111/j.1365-2869.2008.00662.x. Epub 2008 Jun 28.


Related Articles By Cathe:

Three Types of Foods We Crave and Why

Does the Texture of a Food Influence How Much You Eat?

5 Things to Do When Your Eating Habits Get Off Track

6 Tips for Making Healthier Choices at the Grocery Store

Can Consuming More Dietary Micronutrients Curb Hunger?

Sugar May Taste Sweeter to You Than Someone Else


Hi, I'm Cathe

I want to help you get in the best shape of your life and stay healthy with my workout videos, DVDs and Free Weekly Newsletter. Here are several ways you can watch and work out to my exercise videos and purchase my fitness products:

Get Your Free Weekly Cathe Friedrich Newsletter

Get free weekly tips on Fitness, Health, Weight Loss and Nutrition delivered directly to your email inbox. Plus get Special Cathe Product Offers and learn about What’s New at Cathe Dot Com.

Enter your email address below to start receiving my free weekly updates. Don’t worry…I guarantee 100% privacy. Your information will not be shared and you can easily unsubscribe whenever you like. Our Privacy Policy