Dear doctor

Preventing a hangover

Q What is the most scientific method of preventing a hangover?

A Hangovers are related to how much you drink, what you drink, and who you are. Drinking more than five units (two-and-a-half pints of beer or five glasses of wine) can lead to a hangover in most of us. Rum, brandy and whisky are more likely to cause a hangover than white wine, gin or vodka because they contain methanol, formaldehyde and formic acid which are the chemicals most likely to cause the headache and rapid heart rate of hangovers. To prevent a hangover, drink a glass of water for every alcoholic drink and line your stomach first with food. The French like a spoonful of olive oil, the Italians like a boiled potato, the Russians are said to favour half a pound of fat and the British seem to favour a bag of chips or a curry. Keep your head upright to avoid that unpleasant sensation of descending into a whirring pit when you lie down - caused by alcohol getting into the inner ear and upsetting your balance. Most hangover cures don't work, apart from paracetamol for the headache and a couple of Rennie's for the nausea. The Swiss like to breathe pure oxygen, Italians eat coffee with ash and Jamaicans rub lemons and limes under their armpits. I have no idea whether any of these traditional remedies work.

Help! I weigh 19 stone

Q I'm a 32 year old man, 5ft 10in and very overweight. I weigh around 19 stone and have been told I must lose weight or risk serious illness. I've tried really hard - working out at the gym and watching what I eat, but have only managed to lose a few pounds. My GP has offered me Xenical but I don't like the sound of the side effects. What do you think?

A I'd take it if I were you. Orlistat (Xenical) stops you absorbing up to a third of the fat you eat by blocking the effect of the chemicals produced by the pancreas and stomach that let you absorb fat. You take a 120mg tablet with each meal. If you don't stick to a low fat diet, you may well get oily diarrhoea and unpleasant wind - which is quite a strong incentive to stick to a healthy diet. If you take 100 very overweight people who try to stick to a low calorie diet and take more exercise, 15 of them will lose 10% of their total weight in a year. With Orlistat, this goes up to 30. So it's not a guarantee, but it can boost your efforts.

What is a placebo?

Q My GP told me recently that I could take vitamin supplements if I wanted to because it would be a good placebo if nothing else. I wondered where the term 'placebo' came from but my GP didn't know. Do you?

A I didn't, until you asked. But some hasty research reveals that it's from the Latin meaning 'I shall please'. It was apparently used in the 14th century to mean hired mourners and, by 1785, was being used to mean a medicine. By 1811 it had taken on its modern usage, meaning a medicine intended to please rather than benefit the patient. In 1933 it was used to describe an inert treatment given to a control group against which the effectiveness of an active drug was measured. Doctors often say 'it's just placebo' meaning that a treatment is only doing you good because you think it is, not because of any measurable effect. But placebo has the advantage of not doing any harm, and the feelgood effect accounts for up to a third of our responses to medication. So I think we should say: 'Just because it's placebo, doesn't mean it's not working.'

Am I a chocolate addict?

Q What is it about chococolate that makes it so irresistable? I really want to cut down on my daily Fruit and Nut and nightly Celebrations but can't kick the habit. Any tips?

A Chocolate is choc-a-bloc with chemicals that activate our nervous system sending messages of subliminal delight through our brains. The fat and sugar give it its characteristic yummy texture and taste, and the high magnesium levels may appeal to those lacking in this trace element. You could try willpower (boring but worthy) or try a new line while you gorge yourself: 'I'm not a greedy pig, I'm just keeping up my magnesium levels.' But you are seeking advice from another chocaholic - I'm the wrong person to ask.

• These answers are intended to be as accurate and full as possible, but should never be used as a substitute for visiting a doctor and seeking medical help. If you have a question for Dr Robinson, email drann@dircon.co.uk or write to her c/o The Health Editor, The Guardian, 119 Farringdon Road, London EC1R 3ER. She regrets that she cannot enter into personal correspondence.

Thanks to guardian.co.uk who have provided this article. View the original here.