A pub -based experiment has found that people can be nudged into drinking less by downsizing the traditional beer pint glass, it was recently announced. It isn’t the only idea on the table for trying to get people to cut their alcohol consumption – but the science is surprisingly unclear about just how much alcohol is really bad for your health. So what do we know about whether you should be swapping your pints for smaller measures? One certainty is that drinking to excess damages health in a range of ways, from causing cirrhosis of the liver, to heart attacks and strokes, to raising the risk of various forms of cancer.
But there is debate about what level of alcohol consumption you have to reach before the harms kick in. The uncertainty stems from the fact that the most reliable kind of medical research, the randomised trial, would be impossible to carry out when it comes to alcohol. It would be unethical to ask people to drink a certain amount for several years and compare their health to those who drank a smaller amount.
Instead, we have to look at the health of people who have chosen their levels of drinking for themselves, but this kind of study is prone to bias, as heavy drinkers tend to be unhealthy in multiple other ways as well as their alcohol consumption. The guidance Current NHS advice is that both men and women should drink no more than 14 units a week, spread out over at least three days. This is equivalent to seven pints of lower-strength lager or just over.