Behavioural treatments
These include cognitive behavioural therapy which aims to alter attitudes about comfort eating, and anxiety about lack of food availability and the moral duty to finish meals. There is, however, a high relapse rate after this type of therapy.

Drug treatment
Drugs which increase the metabolic rate These include thyroxine, amphetamines, fenfluramine and dexfenfluramine. These have all been used in the past, but reduce the lean body mass as well as adipose tissue, and have other adverse side-effects.

Orlistat
This inhibits lipase action within the gut and reduces fat absorption. It may cause diarrhoea with malabsorption, but is effective in leading to weight loss. It increases insulin sensitivity and also reduces low-density lipoproteins.

Sibutramine
This is a 5HT and noradrenaline re-uptake inhibitor.

It is as effective as orlistat in leading to weight loss, but may cause hypertension and tachycardia.

Bariatric surgery
Liposuction of large quantities of fat reduces body weight to a corresponding degree, but does not have any significant metabolic effects or lead to changes in feeding behaviour. In contrast, surgery directed to the gastro-intestinal tract does not cause any immediate weight loss, but alters feeding behaviour and may assist the subject to obtain more control over what is eaten. Bariatric surgery is of two types.

Restrictive
This reduces the capacity of the stomach and small intestine through techniques such as resection of part of the stomach and banding of the stomach. Newer techniques allow the gastric banding to be adjusted according to the effect that it has on food intake.
Both of these methods reduce ghrelin production and thereby reduce appetite.

Malabsorptive
This includes techniques such as bilio-pancreatic diversion and proximal gastric bypass. These have complex hormonal effects. Proximal gastric bypass, for instance, appears to significantly increase neuropeptide Y.

These surgical methods may lead to dramatic weight loss, particularly in the grossly obese, together with secondary benefits, such as improvement in hypertension, serum lipids and insulin resistance. They are usually reserved for subjects whose body mass index is greater than 40.

References