The study by the University of Leeds involved 1,615 adults who reported how long they slept and kept records of food intake. It also measured other indicators of overall metabolic health such as blood pressure, blood cholesterol, blood sugar, and thyroid function as well as weight and waist circumference recorded.
Those who slept for six hours or less a night had waists that were on average 1.1 inches (3cm) larger than those who slept for nine hours. Shorter sleep was also linked to reduced levels of good cholesterol which helps remove fat from the body and protects against conditions like heart disease.
Dr Greg Potter, a researcher in metabolism at Leeds University, said: “The number of people with obesity worldwide has more than doubled since 1980. “Obesity contributes to the development of many diseases, most notably type 2 diabetes. Understanding why people gain weight has crucial implications for public health.”
Crucially, the study did not find any relationship between shortened sleep and a less healthy diet – a fact that surprised the researchers. Other studies have suggested that shortened sleep can lead to poor dietary choices. But the new research suggests that it is the sleep itself which is driving the effect.



