Research has shown that obesity markedly increases the risk of depression. One study of more than 9,000 adults concluded that depression, and other mood and anxiety disorders, were about 25% more common in the obese people studied than in the non-obese.
Several community surveys in the United States and Canada have shown associations between obesity and depressive symptoms, history of depression, and measures of psychological distress.
Diet Soda and Metabolic Syndrome
A 2008 at the University of Minnesota tracked over 9,000 people and their health for nine years. The investigators discovered that those who drank one can of diet soda a day were 34% more likely to develop metabolic syndrome than those who didn’t. Fifty-nine percent of Americans drink diet soda.
Science suggests that the artificial sweeteners in diet sodas and other foods may actually trick the brain into thinking it’s time to eat more. A 2008 study at Purdue University noted that rats who consumed artificial sweeteners consumer more calories later, and gained more weight.
Rats in the study that were fed yogurt sweetened with no-calorie saccharin took in more total calories and gained more weight than rats fed yogurt sweetened with sugar. Scientists speculate that over time, reduced-calorie sweeteners like saccharin, aspartame, and sucralose condition the body to no longer associate sweetness with calories, thereby disrupting its ability to accurately assess caloric intake. This disruption, in turn, leads to overeating.
The study concluded that artificial sweeteners actually changes brain chemistry as well as metabolism. The number of Americans who consume soda, yogurt and other products containing sugar-free sweeteners more than doubled from 70 million in 1987 to 160 million in 2000. Over the same period, the incidence of obesity among U.S. adults rose to from 15 to 30%.