How Does Junk Food Affect the Way You Concentrate?

A young man eating potato chips while studying in a dorm room.
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When the 2 o'clock slump hits you, you may be tempted to make a run for the vending machine for your favorite candy bar or drink a sugary soda. While these items can certainly make you feel alert for a short period of time, they do more harm than good when it comes to your concentration. Junk food can actually affect your energy level and the way that you process information. The Pew Research Center notes that 55 percent of Americans admit to eating too much junk food, so it's a real concern for adults and children alike.

Sugar High -- Sugar Crash

When you eat junk food, which is typically high in fat, sugar and calories, your body digests the foods fairly quickly. Since junk food has been stripped of nutrients, your body is forced to use the sugar as energy for your body. That energy is spent quickly because of the refined nature of junk food, which means you experience a temporary "sugar high," or false feeling of energy, that is quickly followed by a "sugar crash," or a sensation of fatigue, once your metabolism has burned all of the possible energy. This can lead to bouts of focus loss, fatigue and a loss of concentration.

Behavioral Effects

Eating junk food may seem innocent enough until you realize how it's affecting your behavior, cognition and focus. A 2009 study published in the "European Journal of Clinical Nutrition" found that children who indulged in a diet high in junk food were more likely to be hyperactive than those who did not. Hyperactive children generally lack focus and may not be able to concentrate on simple tasks. The same could be assumed for adults who eat a diet high in junk food; hyperactivity, a lack of focus and an inability to concentrate could affect your work, your relationships and your lifestyle.

Fatigue and Cognition

A study performed by researchers at Oxford University, published in "FASEB Journal" in 2009, tested the cognitive effects on rats that ate a high fat, junk food diet. After nine days on the diet, the rats that ate junk food were put into a maze with rats that ate a more balanced diet. The junk food rats made more mistakes and did poorly while in the maze, while the regular diet rats generally did well. While the effect has not been tested on humans, it could be hypothesized that not giving your body proper fuel can cause cognitive difficulties. When paired with the fatigue of a sugar crash, it can spell mistakes at work, less alert driving or a lessened ability to weight options and make decisions.

Changing Habits

Luckily, the effect that junk food has on your concentration, cognition and focus can be easily reversed by a change in your habits. By choosing foods made from complex nutrients, your body breaks down the food slowly, releasing a steadier supply of energy through your metabolism. Eating a diet high in complex carbohydrates, fiber, lean protein and fruits and vegetables can help you retain more energy so you're better able to concentrate at work and at home.