According to scientists from the Institute of Food Research, 'addicts' blame the chocolate to explain away guilt at having breached social norms - for example, that chocolate should be eaten with restraint.
They told the Biscuit, Cake, Chocolate and Confectionery Alliance: 'An explanation of excessive consumption of chocolate in terms of dependence may be more personally and socially acceptable than the idea that this is an indulgence for the sake of pleasure.'
Chocolate is the archetypal 'addictive' food, according to Dr David Mela and Dr Peter Rogers, from the consumer sciences department of the institute, part of the Agricultural and Food Research Council. It tops the league of 'difficult to resist' foods - ahead of strawberries and biscuits - and is the subject of 60 per cent of all food cravings. Consumption has increased by half since the mid-1970s.
Two-thirds of food cravings occur in the evenings, Dr Mela said. They are associated with boredom and anxiety and are often preceded by 'dysphoric' or highly negative moods. Although chocolate contains psychoactive ingredients, research indicated it was not addictive. However, studies have hinted that cravings might share a common mechanism with opiate drug addiction.
Sweetness, for instance, has an analgesic property: sucrose solutions calm babies more quickly than water. Dr Mela said it appeared to stimulate the production of pleasure-producing opioids by the body. Chocolate contained substances similar to those released by the brain when a person falls in love.
The Government has set targets of reducing saturated fats by 35 per cent and obesity by at least 25 per cent by 2000. Dr David Buss, head of nutrition at the Ministry of Agriculture, said a Mars bar would use up half a person's daily sugar allowance and up to 30 per cent of the fat allowance. He urged manufacturers to make healthy products cheaper than high-sugar, high-fat ones.
Dentists have called for a 'sweet-tooth tax' similar to that imposed on tobacco and alcohol to pay for NHS treatment of tooth decay. The General Dental Practitioners Association claims pounds 1bn could be raised if a 10 per cent tax was imposed on confectionery.