Review of 116 clinical trials finds less than 30 minutes a day, five days a week only results in minor reductions

People who want to lose meaningful amounts of weight through exercise may need to devote more than two-and-a-half hours a week to aerobic training such as running, walking or cycling, researchers say.

The finding emerged from a review of 116 published clinical trials that explored the impact of physical exercise on weight loss, waist size and body fat. In total, the trials reported data for nearly 7,000 adults who were overweight or obese, meaning their body mass index (BMI) was more than 25.