Eat less and exercise more - it has long been the
mantra for shedding those extra pounds. But now it seems that all the hard work
may have been in vain.
Scientists say there are ten other reasons why people just keep getting
bigger. They 
claim that sleeping habits, central heating, medicines and even some
pollutants can play a role in weight gain.
Traditionally, health practitioners have focused on diet and exercise - and a
large dose of willpower - to treat the problem.
However the scientists from top U.S. and Canadian universities say that these
other factors must be considered.
Lack of sleep could be partly to blame, they say in the International Journal
of Obesity. In recent years, the average night's sleep has dropped from nine
hours to just seven.
Sleep deprivation alters levels of the hormones that regulate food intake and
body fat and increase hunger and appetite.
If it is too hot or too cold, we burn calories to cool down or heat up. But
if the temperature is just right, the calories may be turned into body fat
instead.
Those who take beta-blockers to control their blood pressure can often put on
3lb. Similarly, studies have shown that going on the Pill can add 11lb to a
woman's weight.
Mother Nature may also be to blame, with our body shape being partly
inherited. The overweight are also more likely to settle with partners of a
similar size, and their children are more likely to be obese.
And the use of pollutants is on the rise, say the researchers. The manmade
chemicals in pesticides and plastics can interfere with our hormones and lead to
weight gain.
Your mother's age and your weight at birth are also important, with older
women more likely to have obese children and underweight babies having a bigger
chance of being obese in later life.
We are also living longer and tend to put on weight as we get older. Finally,
giving up smoking can also help pile on the pounds.
The scientists from Yale, Cornell and Johns Hopkins said there was only
'circumstantial' evidence supporting poor diet and lack of exercise as the main
causes of obesity.
Eating trends in Britain would change dramatically if everyone followed
official dietary advice, research shows.
Consumption of fresh vegetables would have to rise by 50 per cent to hit
recommended targets.
The amount of bread and fish eaten would increase by 45 per cent and 42 per
cent respectively.
Butter would cut out entirely and cheese consumption would go down by 75 per
cent, the University of Reading researchers found.
OTHER FACTORS BEHIND THE FLAB
Sleep - Too little increases appetite
Medicine - Many modern
medicines lead to us putting on weight
Mother's age - Older women are more
likely to have obese children
Choice of partner - Overweight people tend to
pair with each other - and have overweight children
Heating and air
conditioning - 'Comfortable' temperatures stop us from burning off fat
Genes
- Body shape may be partly inherited
Giving up smoking - Nicotine
suppresses the appetite
Manmade chemicals - Some chemicals interfere with
hormones that keep fat levels low
Weight at birth - Underweight babies have
a bigger risk of obesity
Getting older - Weight tends to increase with
age
