A junk-food diet typically features a high proportion of processed and fried foods, refined sugars and cereals, processed meat, candy and chocolate and high-fat dairy products. Junk food is known as such because its nutritional value is typically outweighed by the dangers it poses to your overall health.
Writing for the Mayo Clinic's website, registered dietitian Katherine Zeratsky explains that a diet high in junk food may have negative effects on your mental health and well-being. Zeratsky cites a study that followed 3,000 British office workers over a period of five years, and found that those eating a junk-food diet were most likely to report symptoms of clinical depression. Additionally, Zeratsky notes studies showing a junk-food diet may increase your risk of developing Alzheimer's or Parkinson's diseases later in life.
Writing in the October 2007 issue of the "British Journal of Nutrition," Stephanie Bayol and colleagues at the London-based Royal Veterinary College reported that a junk-food diet typically leads to obesity due to the diet's high fat, energy, sugar and salt contents. Combining a diet high in junk foods with a lack of exercise and poor appetite control greatly increases your risk of becoming obese. Obesity increases your risk for many health problems and diseases including heart problems, stroke and cardiovascular disease.
Fetal and Infant Health
Bayol and colleagues also indicated that it is possible an infant's appetite for food, and his overall body mass, are affected when his mother eats a diet high in junk food during pregnancy and breastfeeding. In 2007, Bayol's research team studied the impact of maternal junk-food consumption of animals on the dietary preferences and body mass index of their offspring. Although the results of an animal study cannot be assumed to correlate directly to human health, Bayol concludes that a mother eating a junk-food diet increases the risk of her child developing less-healthy appetite preferences and obesity later in life.
Junk food, and processed food in general, is typically much higher in salt (sodium chloride) than freshly prepared food. Most people in the United States regularly consume significantly more sodium than is necessary, leading to an increased risk of high blood pressure and other health problems. As at January 2010, the Mayo Clinic reports, U.S. health authorities recommend a healthy adult eats no more than 2,300 milligrams of sodium daily; authorities including the Institute of Medicine have suggested lower healthy sodium limit of 1,500 mg daily. Many junk foods have a much higher sodium content than these daily recommended limits — a 1.5-ounce serving of McDonald's spicy buffalo sauce, for example, contains 2,140 mg of sodium, the SMI Analytical website calculates.