In 1980, approximately 5 percent of men and 8 percent of women were obese. This jumped to 10 percent of men and 14 percent of women in 2008. Now 67 percent of adults are overweight or obese according to the Australian Institute of Health and Welfare. Excess weight, especially obesity, is a major risk factor for cardiovascular disease, type 2 diabetes, some musculoskeletal conditions and some cancers.
As the level of excess weight increases, so does the risk of developing these conditions. “The diet in the U.S. and other nations has changed dramatically in the last 50 years or so, with highly processed foods readily and cheaply available at any time of the day or night,” says Ali Güler, a professor of biology at the University of Virginia. “Many of these foods are high in sugars, carbohydrates and calories, which makes for an unhealthy diet when consumed regularly over many years.”
A new study from the University of Virginia has shown how snacking on these unhealthy foods leads to obesity. The researchers found that the pleasure centre of the brain and the brain’s biological clock are linked, and that high-calorie foods — which bring pleasure — disrupt normal eating schedules, resulting in overconsumption. Güler’s team found that mice fed a diet comparable to a wild diet in calories and fats maintained normal eating and exercise schedules and proper weight. But mice fed high-calorie diets laden with fats and sugars began “snacking” at all hours and became obese.
Other studies have shown, Güler said, that high-fat foods eaten between meals or during what should be normal resting hours, are stored as fat much more readily than the same number of calories consumed only during normal feeding periods. This eventually results in obesity and obesity-related diseases, such as diabetes. Speaking of the modern human diet, Güler said, “The calories of a full meal may now be packed into a small volume, such as a brownie or a super-size soda. It is very easy for people to over-consume calories and gain excessive weight, often resulting in obesity and a lifetime of related health problems.”
