- Two experts have studied the link between exercise and obesity for years
- Trials show exercising and dieting is no more effective than dieting alone
- When people exercise, their appetite increases and they eat more food
- The only way to lose weight is to eat fewer calories, they concluded
Most people hoping to shed a few pounds head straight for the gym.
But the miles they clock up on the treadmill may not actually help them lose any weight, scientists now claim.
Doing more exercise increases a person's appetite, and they tend to eat more food as a result, the researchers said.
Therefore controlling calories – with or without increasing physical activity - is the key to maintaining or losing weight, they concluded.
This crucial part of the public health message is not appreciated in recommendations to be more active, walk up stairs and eat more fruits and vegetables.
'The prescription needs to be precise: There is only one effective way to lose weight - eat fewer calories.'
Numerous clinical trials have found that exercising as well as restricting calories achieves virtually the same weight loss calorie-restriction alone, they said.
And other studies show no link between the energy someone expends (through exercise) and subsequent changes to their weight. They added that only 'extremely small' proportions of the US population do enough physical activity to affect their long term balance of energy.
Therefore, they argue that that physical activity does not influence obesity, they said.
They concluded: 'While physical activity has many benefits, multiple lines of evidence lead to the conclusion that an increase in physical activity is offset by an increase in calorie intake, unless conscious effort is made to limit that compensatory response.'
Last year, Dr Michael Mosley, the brains behind the popular 5:2 diet, warned that exercise can actually cause us to gain weight. 'A lot of people think that when you exercise, you can eat what you want - and that the gym will make you happy,' he said.
But this is wrong.
'Going to the gym will burn calories - but way less than we think. '1lb of fat is 3,500 calories - and fat is more energy-dense than dynamite' - so to burn 1lb of fat you'd need to run about 38 miles.'
He cites the example of a muffin and latte - which many of us underestimate the calorie content of. 'If you run one mile, you burn roughly 100 calories,' he told presenters Ruth Langsford and Eamonn Holmes. 'A muffin contains around 500 calories - so you would have to run for five miles or walk for 10 miles to burn it off.' And when it comes to a latte - which has around 150 calories - it would be 1.5 miles of running or a three-mile (hour long) walk. 'That is why people never lose weight going to the gym in the long-run.
Sources: http://www.sciencedaily.com/, http://www.newswise.com/, http://www.dailymail.co.uk/