The International Atomic Energy Agency (IAEA) has published helpful new data from its Doubly Labelled Water (DLW) Database, which provide insights on the effectiveness of exercise to spur weight loss.

The results aren’t as straightforward as you may think.

“When enrolled into exercise programmes for weight loss, most people lose a little weight, some individuals lose lots, but a few unlucky individuals actually gain weight”, said John Speakman, chair of the DLW Database Management Group and one of the study’s authors.

Treadmill effect

According to the study, in individuals with a normal body mass index of between 18.5 and 24.9, the body will offset calories burned during exercise by 28 percent – meaning just 72 percent of the calories will be lost over the course of the day.

However, with age and weight, this ratio drops, and those with the highest body mass index will only lose 51 percent of the calories burned in exercise.

The study confirms that individuals differ in the way their bodies budget energy use, and people living with obesity may have difficulty losing weight as their bodies are efficient at hanging onto their fat storage.