Gym won't make girls slim

Women who spend hours on the treadmill in search of the perfect body might be wasting their time.

A study today shows that women find it harder than men to lose weight through exercise, casting doubt on claims that working out alone can help shift fat.

Researchers studied a group of overweight men and women to try to find out whether they would be able to lose weight without changing their eating habits.

The group could eat what they liked but worked out on a treadmill for 45 minutes a day, five days a week.

When they were weighed at the end of the trial, almost all the men had lost weight. The women had not.

The research team at the University of Kansas says the women burned fewer calories because they are physically smaller than men, and that the results prove people keen to lose weight need to combine regular exercise with a diet regime.

Those who sweated through the experiment ate no differently, in terms of percentage of carbohydrates, fats and protein, than a control group who took no formal exercise.

Nik Cook, a senior personal trainer at Matt Roberts Personal Training in Jermyn Street, Piccadilly, agreed it is easier for men to burn fat in the gym. "Men have higher levels of testosterone, which allows them to put on muscle quicker, and also have more lean tissue," he said.

Amanda Wynne from the British Dietetic Association said: "It is essential to consider diet as well as exercise in a weight-loss programme, although the women may have replaced fat with muscle, which weighs more. So it would probably be helpful to look at whether their waistlines were smaller after the exercise programme.

"It is also likely the women responded to increased feelings of hunger after exercise by eating more. However, they would have benefited from improved circulation and cardiovascular fitness."