Weight loss does not equal true health or fitness, according to a new study published in the official journal of the American College of Sports Medicine, shedding new light on the 'fit versus fat' debate.

Dr Enette Larson-Meyer directed 36 overweight adults to participate in one of three programmes during a six-month intervention: diet alone, diet plus exercise, or a weight-maintenance programme (the control group). The diet-only and weight maintenance groups were instructed not to change their physical activity regimens during the six-month period.

Although both the diet and diet-plus-exercise groups lost weight during the course of the study – around 10 percent of total body weight – only the exercising individuals improved their internal fitness in addition to their waistlines.

“We saw marked improvements in cardiovascular fitness, blood pressure, insulin sensitivity and cholesterol levels in the individuals who regularly exercised,” Larson-Meyer said.

Men in the study burned around 500 calories each exercise session and women burned around 400 – approximately 12.5 per cent of their daily calorific needs. Participants were allowed to choose their own exercise type and intensity according to what activities they enjoyed, as long as the intensity level fell between 65 and 90 per cent of their maximal heart rate.

Larson-Meyer said this choice was important, as “some [study participants] preferred a higher heart rate and enjoyed shorter exercise sessions, while others liked a more leisurely pace – even knowing they would have to exercise longer.”