Junk food is an informal term applied to some foods that are perceived to have little or no nutritional value (i.e. containing "empty calories"); to products with nutritional value, but also have ingredients considered unhealthy when regularly eaten; or to those considered unhealthy to consume at all. The term was coined by Michael Jacobson, director of the Center for Science in the Public Interest, in 1972.
Junk foods are typically ready-to-eat convenience foods containing high levels of saturated fats, salt, or sugar, and little or no fruit, vegetables, or dietary fiber; and are considered to have little or no health benefits. Common junk foods include salted snack foods like chips (crisps), candy, gum, most sweet desserts, fried fast food and carbonated beverages (sodas) as well as alcoholic beverages.
Remember, junk foods are empty calories. An empty calorie lacks in micro-nutrients such as vitamins, minerals, or amino acids, and fiber but has high energy (calories).
Health effects
A study by Paul Johnson and Paul Kenny at The Scripps Research Institute suggested that junk food consumption alters brain activity in a manner similar to addictive drugs like cocaine or heroin. After many weeks on a junk food diet, the pleasure centers of rat brains became desensitized, requiring more food for pleasure. After the junk food was taken away and replaced with a healthy diet, the rats starved for two weeks instead of eating nutritious fare. A 2007 British Journal of Nutrition study found that mothers who eat junk food during pregnancy increased the likelihood of unhealthy eating habits in their children.
A report published in the Journal of the Federation of American Societies for Experimental Biology suggests that babies of mothers with a high-sugar and high-fat diet while pregnant are more prone to junk food themselves. The study was conducted on rats and suggests that "infants whose mothers eat excessive amounts of high-fat, high-sugar junk foods when pregnant or breastfeeding are likely to have a greater preference for these foods later in life."
A 2008 report suggests that mothers who eat junk food while pregnant or breast-feeding have children who are more prone to obesity. The children are also more prone to diabetes, raised cholesterol, and high blood fat.
Junk food diet in early childhood may lower IQ
Washington, Feb 8 : Children fed chips, pizza and other junk foods are likely to have lower IQs, says a new research.
Researchers said that a diet, high in fats, sugars, and processed foods in early childhood may lower IQ, while a diet packed full of vitamins and nutrients may do the opposite.
The findings are based on participants in the Avon Longitudinal Study of Parents and Children (ALSPAC), which is tracking the long term health and well being of around 14,000 children born in 1991 and 1992.
Parents completed questionnaires, detailing the types and frequency of the food and drink their children consumed when they were 3, 4, 7 and 8.5 years old.
Three dietary patterns were identified: "processed" high in fats and sugar intake; "traditional" high in meat and vegetable intake; and "health conscious" high in salad, fruit and vegetables, rice and pasta. Scores were calculated for each pattern for each child.
IQ was measured using a validated test (the Wechsler Intelligence Scale for Children) when they were 8.5 years old. In all, complete data were available for just under 4,000 children.
The results showed that after taking account of potentially influential factors, a predominantly processed food diet at the age of 3 was associated with a lower IQ at the age of 8.5, irrespective of whether the diet improved after that age. Every 1 point increase in dietary pattern score was associated with a 1.67 fall in IQ.
On the other hand, a healthy diet was associated with a higher IQ at the age of 8.5, with every 1 point increase in dietary pattern linked to a 1.2 increase in IQ. Dietary patterns between the ages of 4 and 7 had no impact on IQ.
The authors say that these findings, although modest, are in line with previous ALSPAC research showing an association between early childhood diet and later behaviour and school performance.
"This suggests that any cognitive/behavioural effects relating to eating habits in early childhood may well persist into later childhood, despite any subsequent changes (including improvements) to dietary intake," they say.
The brain grows at its fastest rate during the first three years of life, say the authors, by way of a possible explanation for the findings, adding that other research has indicated that head growth at this time is linked to intellectual ability.
"It is possible that good nutrition during this period may encourage optimal brain growth," they suggest, advocating further research to determine the extent of the effect early diet has on intelligence.
The study has been published online in the Journal of Epidemiology and Community Health.
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