Although John Prescott, the former deputy Prime Minister, had to resort - like an Ancient Roman emperor - to self-induced vomiting so that he could continue to enjoy gargantuan meals, he still became massively overweight.

Unlike patients suffering from anorexia nervosa, those with bulimia are often of normal weight or even overweight. The underlying psychological basis of these two eating disorders, and therefore the motivation - whether subconscious or conscious, is frequently different, as is their treatment.

Even if grossly overweight patients do succeed in losing their redundant stones, rather than pounds, they shouldn't immediately expect to look svelte enough to be the centre of attraction on Silvio Berlusconi's yacht.

After a successful slimming campaign, with or without surgical help - a dilemma that shrinking Alison Hammond, the This Morning TV presenter, was said to have wrestled with recently (allegedly a gastric band winning out) - there usually remains the problem of what to do with skin that is left hanging in sagging folds. These folds are obvious after any excessive weight loss, whether by dieting or gastroplasty - the surgery that remodels a patient's stomach so that, post operatively, it has the capacity of a large syringe. Once a patient is left with such a small stomach, their hunger is swiftly satisfied.

Gastroplasty is not without substantial risk, so patients are usually considered for this operation only when they are more than twice their ideal weight for their height, and have a BMI (body mass index) of 45 or above.

Liposuction, the sucking out of liquid fat using a small tube, is one way of helping some patients to regain their shape. This procedure is usually reserved for the removal of relatively small fat reserves. Although liposuction is not such a major procedure as abdominoplasty, it can still have troublesome side-effects, especially if the patient is immobile for any length of time. Nor does liposuction overcome the problem of excessive, redundant skin.

Abdominoplasty is the operation once referred to as an apronectomy or, popularly, a tummy tuck. This operation removes both fat and excess skin. During an abdominoplasty, the surgeon makes a curved cut from the top of one hip to the other and removes excess skin, subcutaneous tissue and fat between the pubic area and the umbilicus, or belly button. The skin above the umbilicus is then pulled down to join the skin above the pubis. If this leaves the umbilicus significantly out of place, it can be repositioned farther up the abdominal wall.

A variant of the standard abdominoplasty is the mini-abdominoplasty. This operation is more like the tummy tuck that patients often expect. The procedure involves removing excess skin and fat between two comparatively small cuts made above the pubic area. The skin and tissue removed is shaped like a large segment of orange. Liposuction may also be used in addition to abdominoplasty either before, during or after the operation.

Sometimes the surgeon will find that a sagging abdomen is the result of slack muscles rather than excess fat. If so, a rigorous exercise programme may help. In some cases, endoscopic (keyhole) surgery may be used to tighten the muscles in the abdominal wall.

Some patients find that, in spite of slimming, they are still self-conscious and may be reluctant to expose their bodies - for example in changing rooms, at the swimming pool or at the beach. They may be wise to seek the help of skilled surgeons.

The McIndoe Surgical Centre is a private medical unit built on the campus of Queen Victoria Hospital, East Grinstead. It was made famous by Sir Archibald McIndoe during the Second World War when it treated burns victims and reconstructed patients' faces and limbs, and it now specialises in cosmetic surgery of the face, breasts and abdomen. The main Queen Victoria Hospital still works within the NHS.

The senior consultant plastic and reconstructive surgeon at the centre is Nick Parkhouse, who was recently speaking at a meeting in London. He has the assurance, charm and skill that is characteristic of an “old school” surgeon but, unlike Sir Lancelot Spratt, the character in Richard Gordon's Doctor books, arrogance is replaced with humanity. He understands a patient's anxieties and the erosion of feelings of self-worth caused by sagging breasts, bottoms and abdomens.

The Roman emperors and their subjects didn't have to contend with the temptations of supermarkets packed with doughnuts and chocolates, but they still managed to gorge on wine, pigeon, honey and pasta.

Nor did the Romans have skilful surgeons on hand to drain away excess fat or cut away folds of loose skin. However, they did appreciate the value of exercise.

Breast and abdominal reconstruction can make an amazing difference. However, Parkhouse has stressed that patients who are successfully treated will maintain their trim physique only if they make a conscious effort to avoid being slothful or overindulgent.