This could be why you're fat - 1

GRADUAL, CREEPING WEIGHT GAIN

COULD BE: Slow metabolism or extreme dieting.

After the age of 30, your metabolism (the rate at which we burn calories while we are at rest) slows down by as much as 5 per cent per decade.

You’ll burn 100 fewer calories per day at the age of 35 than you did at 25, and 200 fewer at 45. This could be enough to trigger an annual weight gain of 8-12lb.

Strict (or yo-yo) dieting makes this process worse (whatever your age), as the body slows the metabolism to avoid wasting any energy while it is dealing with what it considers to be a famine.

WHO'S AT RISK? Anyone over 30; dieters.

WEIGHT-LOSS SOLUTION: As well as being generally more active, incorporate weight-training into your exercise routine twice a week to build muscle mass, because this will boost your metabolic rate.

Muscle burns 25 to 33 per cent more calories than body fat does, and each pound of muscle boosts your metabolic rate when resting.

If you replace 10lb of fat with 10lb of muscle, your body will burn roughly 40 more calories a day at rest. This doesn’t sound like much, but it accumulates to become 280 extra calories burned a week, and 1,120 a month — that’s enough to lose weight without dieting.

So add a few press-ups, squats and lunges to your fitness programme, or try an exercise DVD that incorporates resistance bands or weights (whether that’s using bottles of water or dumbbells), or alternate your aerobics class with something such as Body Pump, which is weight-training to music