Sleeping badly could be driving weight gain, scientists fear, after finding that people who slept just six hours a night had waist measurements an inch greater than those who get nine hours.

The results strengthen the evidence that insufficient sleep could contribute to the development of metabolic diseases such as diabetes.

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.