Fast Food: The Fast Track to Weight Gain
People who frequently eat fast food gain more weight and are more likely to develop insulin resistance than people who don’t, according to a study in The Lancet (2005;365:36–42).
Overweight and obesity is now epidemic in the United States, affecting two out of three adults. The proportion of overweight children is also increasing at an alarming rate, growing 50% in the past ten years to about 15%.
The rising incidence of overweight and obesity has followed some cultural trends in eating habits. An increasing proportion of the food Americans eat is prepared outside of the home. Much of this prepared food is fast food, defined as convenience foods from self-service or take-out eating facilities. Fast foods are generally high in salt, fat, and refined carbohydrates, and low in vitamins and minerals. Additionally, studies have found that portion sizes of prepared foods and fast foods have increased in the thirty years that obesity rates have skyrocketed. It is estimated that more than 10% of the food consumed by children is fast food. Several studies have found that high intake of fast food is linked to high body weight.
This increase in overweight and obesity has lead to a rising incidence of insulin resistance and type 2 diabetes (sometimes called adult-onset diabetes) in young people. Insulin is a hormone produced in the pancreas and released in response to spikes in blood glucose that occur after eating sweets and other carbohydrates. Normally, insulin stimulates cells to take up and utilize glucose; however, in insulin resistance, the body’s cells do not respond adequately to insulin and higher levels are required to bring the blood glucose level down. In people with type 2 diabetes, the cells are often strongly resistant to insulin, and both insulin and blood glucose levels remain chronically elevated. Overeating, having a sedentary lifestyle, and being overweight are major risk factors for type 2 diabetes.
The current study included 3,031 people between ages 18 and 30. Dietary assessment was done through interviews at the beginning of the study and at years 2, 5, 7, 10, and 15; a detailed questionnaire was also used at the beginning of the study and at year 7. Participants’ weight, height, and waistlines were measured and blood tests were done to look for insulin resistance at the time of each interview. Physical activity, hours spent watching television, and other lifestyle factors that could affect weight gain and insulin resistance were measured by questionnaire at the beginning of the study and at 5, 10, and 15 years.
Frequently eating fast food was found to be significantly associated with both weight gain and insulin resistance. People who ate fast food most often (more than two times per week) gained an average of 4.5 kg (about 10 pounds) more than those who ate fast food least frequently (less than once per week). Furthermore, insulin resistance increased twice as much in those who ate the most fast food compared with those who ate the least.
These findings add to the evidence that frequently eating fast food can cause weight gain, and suggest that fast food increases insulin resistance. As fast food consumption can be considered one culprit in the rising incidence of overweight and obesity, it can be hoped that future public health policies will strongly discourage it. The link between fast food and risk of type 2 diabetes needs further investigation.
Maureen Williams, ND, received her bachelor’s degree from the University of Pennsylvania and her Doctorate of Naturopathic Medicine from Bastyr University in Seattle, WA. She has a private practice in Quechee, VT, and does extensive work with traditional herbal medicine in Guatemala and Honduras. Dr. Williams is a regular contributor to Healthnotes Newswire.
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