To understand whether or not there really is a link between dietary choices and the risk of insomnia, the investigators looked for any associations between different diets and sleep disruptions. Gangwisch and colleagues found a link between a higher risk of insomnia and a diet rich in refined carbohydrates. This includes foods with added sugars, soda, white rice, and white bread.
The researchers caution that it was unclear from their analysis whether the consumption of refined carbohydrates led to insomnia, or that people who experienced insomnia were more likely to consume refined carbs, especially sugary foods. However, they do note that there is a possible underlying mechanism that might explain added sugars causing sleep disruptions. "When blood sugar is raised quickly, your body reacts by releasing insulin, and the resulting drop in blood sugar can lead to the release of hormones such as adrenaline and cortisol, which can interfere with sleep," Gangwisch explains.
The study authors also explain why not all foods that contain sugar will lead to the same effect. Fruits and vegetables ? which naturally contain sugar ? are unlikely to raise blood sugar levels nearly as quickly as foods containing added sugars. This is because these natural foods are also high in fiber, which means that the body absorbs the sugar more slowly, preventing a spike in blood sugar levels.