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. Additionally, according to ScienceDaily, 2010 research at Emory University found 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 2004 study published in "The 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.
Depression
Researchers in Britain have discovered a link between depression and junk food, according to MayoClinic.com. 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 published in the "Journal of Epidemiology & 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.
Recommendations
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 g each day -- but ideally, cut it out altogether. Also limit your intake of added sugar to about 100 calories if you're a woman and about 150 calories if you're a man. This translates to about 6 tsp. and 9 tsp. per day, respectively.
References
- University of Iowa Health Care: Kicking the Junk Food Habit
- U.S. Department of Health and Human Services: Fast-Food Restaurants, Weight Gain and Insulin Resistance in Young Adults; December 2004
- ScienceDaily: Higher Amounts of Added Sugars Increase Heart Disease Risk Factors, Study Finds; April 22, 2010
- MayoClinic.com; Junk Food Blues: Are Depression and Diet Related?; Katherine Zeratsky, R.D., L.D.
- Journal of Epidemiology & Community Health: Childhood Dietary Patterns and IQ; K. Northstone, et al; December, 2010
- Harvard School of Public Health: Fats and Cholesterol
