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How Does Junk Food Harm the Body?

author image Christa Miller
Christa Miller is a writing professional with expertise in massage therapy and health. Miller attended San Francisco State University to earn a Bachelor of Arts in creative writing with a minor in journalism and went on to earn an Arizona massage therapy license.
How Does Junk Food Harm the Body?
Corndogs for sale at a food cart. Photo Credit David-Shih/iStock/Getty Images

Junk food is any food that provides too much fat and calories and not enough nutrients. You may have trouble resisting the urge to indulge when commercials, grocery store shelves and fast food restaurants are packed with treats. Consuming small amounts of junk food can be part of a healthy lifestyle, but your body is at risk of serious harm if you don’t monitor your intake.

Higher Cholesterol

Junk foods such as donuts, boxed baked treats, processed foods and restaurant-fried foods contain trans fats. These fats, which are produced by partially hydrogenating various types of oil, have been linked to serious health problems. For instance, they are known to increase your levels of “bad” cholesterol and decrease your levels of “good cholesterol,” which can boost your chances of having heart disease, according to the Harvard School of Public Health. A study by Ms. Jean A. Welsh, M.P.H., R.N. et al., published in the April 21, 2010 issue of the "Journal of the American Medical Association," determined that consuming large quantities of added sugars in junk foods can increase your blood fats and decrease your “good” cholesterol, thus also contributing to your risk of heart disease.

Obesity and Insulin Resistance

When compared with young adults who eat fast food less than once weekly, young adults who eat at fast food restaurants more than twice weekly gain more weight and are more likely to see a great increase in their diabetes and heart disease risk as they reach early middle age, according to a study by Pereira, M.A. et al., published in the January 2005 issue of “Lancet.” Specifically, young adults who ate fast food more than twice per week gained 10 more pounds and had twice the insulin resistance increase. One suspected culprit for the weight gain was the sheer quantity of calories in fast food.


The November 2009 issue of the "British Journal of Psychiatry," contained a report of a study by Tasnime N. Akbaraly, Ph.D., et al. The researchers discovered a link between depression and junk food. As part of the study, middle-aged office workers’ habits were observed for five years. They were more likely to report symptoms of depression when they had a diet high in desserts, fried foods, refined cereals, fatty dairy products, processed meat and chocolate. Conversely, workers whose diet emphasized fish, fruits and vegetables were less likely to report such symptoms.

Lower IQ in Children

Children who consume junk foods such as pizza, chips and biscuits prior to age 3 may end up having lower IQs than children who ate home-cooked foods with fruits and vegetables. According to 2010 research by Kate Northstone et al., published in the Feb. 7, 2011 issue of the “Journal of Epidemiology and Community Health,” these children were tested five years down the line and had IQ scores that were as much as five points lower than their healthier-eating peers. The researchers suspected that the negative effect of eating junk foods so early in life may not be altered by future healthy habits because it is related to hindered brain development.


To reduce your health risk, the American Heart Association recommends that you limit your intake of trans fats to less than 1 percent of your total calories – about 2 grams each day – but ideally, cut it out altogether. Cut daily intake of added sugar to about 100 calories, or 6 teaspoons, for women and about 150 calories, or 9 teaspoons for men. You do not have to give up fast foods if you choose smaller servings, limit or avoid cheese toppings, mayo, high-fat sauces and dressings, breaded or fried foods and sugar-sweetened beverages. Choose instead roasted or grilled chicken, single hamburgers with lettuce and tomato, tacos fresco style, made with salsa instead of cheese, diet soda, water, low-fat salad dressings, yogurt for dessert, and, if you cannot pass them up, order small fries. If you eat fast food more than once a week, the University of Georgia Health Center recommends lean-meat deli sandwiches and vegetables as a healthier choice.

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