Most people know that eating too much dessert and processed food can contribute to physical health problems like obesity and type 2 diabetes. Far less attention has been given to the impact of a high-sugar diet on mental health, though numerous studies have shown the deleterious effects a sweet tooth can have on mood, learning and quality of life. In addition to inflating waistlines(link is external), sugar and other sweeteners, including high fructose corn syrup, honey, molasses and maple syrup, may contribute to a number of mental health problems:
The roller coaster of high blood sugar followed by a crash may accentuate the symptoms of mood disorders. Research(link is external) has tied heavy sugar consumption to an increased risk of depression and worse outcomes in individuals with schizophrenia. There are a couple theories explaining the link. Sugar suppresses activity of a hormone called BDNF that is low in individuals with depression and schizophrenia. Sugar is also at the root of chronic inflammation, which impacts the immune system, the brain and other systems in the body and also has been implicated in depression. Interestingly, countries with high sugar intake also have a high rate(link is external) of depression.
Although controversial, a growing body of evidence points to the addictive potential of sugar. Both drugs and, to a lesser extent, sugar and processed junk foods flood the brain with the feel-good chemical dopamine, over time changing the function of the brain. In a study by researchers at Yale University, the simple sight of a milkshake activated the same reward centers of the brain as cocaine among people with addictive eating habits. A 2007 study(link is external) showed that rats actually prefer sugar water to cocaine. Rats given fatty and sugary products demonstrated classic symptoms(link is external) of addiction including tolerance and withdrawal symptoms when the products were taken away.
The Standard American Diet, which is full of sugar and fat, does not necessarily cause anxiety but it does appear to worsen anxiety symptoms and impair the body’s ability to cope with stress. Individuals who suffer from panic attacks, for example, are hyper-alert to signs of impending danger. Sugar can cause blurry vision, difficulty thinking and fatigue, all of which may be interpreted as signs of a panic attack, thereby increasing worry and fear. A sugar high and subsequent crash can cause shaking and tension, which can make anxiety worse.