London - If your weight-loss goals are eluding you it may be time to change your gym regime – by cutting back.
Going to the gym to lose weight will only succeed for a while because the body adapts to higher activity levels, a study has found.
While pounding the treadmill or hitting the weights will initially reduce that spare tyre, your body will soon start to become less effective at burning calories as it becomes more efficient.
People who start rigorous exercise programmes to shed the kilos often report that their rate of weight loss declines after a few months.
The new research, published in the journal Current Biology, showed a weak but measurable effect of physical activity on daily energy expenditure, but this did not apply to everyone. While moderately active people burned about 200 more calories each day than most sedentary people, those who did higher levels of exercise saw no extra benefit.
“The most physically active people expended the same amount of calories each day as people who were only moderately active,” Dr Pontzer said.
The US researchers measured the daily energy expenditure and activity levels of more than 300 men and women over the course of a week.
Lead scientist Dr Herman Pontzer, from the City University of New York, said: “Exercise is really important for your health. That’s the first thing I mention to anyone asking about the implications of this work for exercise.
“There is tons of evidence that exercise is important for keeping our bodies and minds healthy, and this work does nothing to change that message. What our work adds is that we also need to focus on diet, particularly when it comes to managing our weight and preventing or reversing unhealthy weight gain.”
The research suggests there is a “sweet spot” for physical activity. While too little is unhealthy, too much causes the body to make big metabolic adjustments in order to adapt.
Some of the reduction in lost calories in people who exercise is down to adjusting their bodies while resting – there is evidence that people who exercise vigorously fidget less.
But a further part of the reduction is thought to be bodily changes.
The researchers propose this energy reduction may explain why exercise is good for us as it could reduce the amount of energy the body expends on inflammation and harmful activity such as when one’s own immune system attacks one’s own body.
Dr Pontzer decided to explore the link between activity and energy expenditure after working among the Hadza, a community of traditional hunter-gatherers in northern Tanzania.
He said: “The Hadza are incredibly active, walking long distances each day and doing a lot of hard physical work as part of their everyday life. Despite these high activity levels, we found that they had similar daily energy expenditures to people living more sedentary, modernised lifestyles in the United States and Europe. That was a real surprise.”
Daily Mail