Pharmacological approaches

At the most simplistic level, a drug can cause

weight loss only by reducing energy intake or

by increasing energy expenditure. In practice,

there are several ways of achieving these goals,

and some agents have effects on both sides of

the energy balance equation. Energy intake

can be reduced either by influencing the

mechanisms in the central nervous system that

control appetite, by making a subject feel less

hungry, or more satiated after a meal; the

majority of older appetite suppressants and

the newer agent sibutramine work in this

way.1 An alternative approach is to reduce

absorption of nutrients – the latter will only

be effective, however, if there is no

compensatory increase in food consumption.