Perceived or real fatness causes more angst in the Western world than all other stressors put together. Everyone from Bridget Jones to Fergie has suffered tortured sessions with the scales, endured months of eating lettuce and cardboard (aka crispbread: only advantage- if you run out, you can eat your napkin, which tastes better), and gazed with narrow-eyed envy at waifs who seem to cram themselves with chocolate and still look as if they'd waft away in a light breeze.

Any new diet book is gobbled up by the general public. Like revision timetables for exams, planning diets seems to make us feel good, even if we never get down to the painful reality and hard slog of the work in hand. Our IQs swiftly dwindle to our desired size in Levis - we swallow all sorts of crap, both metaphysically and in reality.

The desire to be fashionably thin, with its associated casualties of anorexia, bulimia, low self-esteem and wastage of time, energy and money, needs to be differentiated from the true states of overweight and obesity, which carry real health problems. Over half the British population are overweight, as defined by a body mass index, or BMI (weight in kg divided by height squared in metres) of greater than 25. Obesity is said to be present when the BMI is greater than 30, and this occurs in an alarming one in seven people.

There are many health problems associated with carrying significant amounts of extra weight. The incidence of heart disease and hypertension are increased, late onset diabetes is more likely, breathing problems are exacerbated, joints come in for increased wear and tear, acid reflux is far more common and many cancers are more prevalent in the overweight.

There are certain people who seem to be able to stuff their faces with calorific grub and never put on an ounce; whereas others will swear they only need to glance at a cake to have it smeared around their hips. Unfortunately, this plaintive line of protest is redundant for two reasons. One is that even if certain people have a higher metabolic rate than others, the hard truth is weight gain only occurs if you expend less energy than you ingest. Even if you have the metabolic rate of an amoeba, you have no real excuse for being porky, as you should simply eat less. Athletes have high metabolic rates because of their activity - it follows that they burn more energy and need to take in a lot in order to maintain their body weight. Conversely, if you lead a sedentary lifestyle, you burn less energy and have a lower metabolic rate. Even if part of your lower metabolic rate is genetically determined,

the fact remains that you burn food slower so you need less - you will be physiologically hungry less often than your active colleagues, so you have no excuse for gorging. Sorry.

The other reason why bleating about metabolic rates is a waste of time is that it's hard luck. Moaning about it ain't gonna make it better. Learned helplessness or self-pitying never helped anyone. Go for a walk instead. This may sound immensely heartless, but it's meant to be helpful. There's no point in spending vast sums on bizarre foodstuffs, poring over pseudo-scientific piffle about food combining, or deluding yourself that eating only one kind of food is salvation. The best way to lose weight and maintain it is to eat less and exercise more. Of course, it's better for your overall health if you choose to do this by eating more healthy foods and cutting out those of poor nutritional value.

There are experimental and real treatments. There are drugs on the market that have been used with varying degrees of success, and all sorts of hormone and neurotransmitter-based drugs in the pipeline. However, as a cynic, I don't hold out much hope for them. Being overweight is a lifestyle problem. Most of us put on the pounds because we like the taste of food, eat when we're bored, or loathe exercise. Drugs may blunt the physiological pang of hunger, but how many people are fat due to true hunger? Even drastic surgical ''cures'' like jaw-wiring and stomach-stapling only work when the psychological willpower is there.

As the unwilling owner of a spare tyre, I'm as lacking in willpower as anyone. All I'm saying is, beware of fads and miracle diets. If you're losing pounds, make it the ones round your waist, not those in your wallet.