It sounds macho, but there’s science behind the idea that bigger men are better at holding their drink. That’s because size matters. A larger person absorbs more alcohol into their body tissue, reducing the amount that reaches their brain, which is when you start to feel its effects.
Sex matters, too. It generally takes less alcohol for a woman to get drunk than a man, due to a combination of factors. Women have lower body water content, which means the alcohol is more concentrated in their bodies. They also have fewer enzymes to help break down alcohol in the stomach, and hormonal differences can worsen intoxication. Other genetic factors — the characteristics your parents pass down to you — also play a part in determining an individual’s tolerance to alcohol.
But those aren’t the only reasons it’s hard to predict exactly how much alcohol you can safely drink.
It also depends on how long it takes for your body to process it and the amount of pure drinking alcohol (ethanol) present in your drink. That is measured by alcohol-by-volume, or ABV, which is typically found on the labels of cans and bottles.
In South Africa, a standard drink is assumed to contain about 15ml of pure alcohol (ethanol), which is typically found in one 340ml can of beer (4.5% ABV), 150ml of wine (12% ABV), or 40ml of whisky (40% ABV).
A useful guide to safer drinking is a blood alcohol content (BAC) calculator, which measures how much alcohol is in your blood at any given moment. The higher your BAC number, the drunker you are.
For example, I weigh 85kg. An hour after drinking two glasses of wine, my BAC is about 0.03%, low enough for me to legally drive. But if my wife, who weighs 61kg, drinks two glasses of wine over the same time, her BAC would be 0.056%, above the legal limit.
While you may only feel really drunk at a BAC of about 0.1g per 100ml of blood (0.1%), drinking far less alcohol can have serious health risks.
The World Health Organisation has concluded that there is no safe level of alcohol consumption
No safe amount
The World Health Organisation (WHO) has concluded that there is no safe level of alcohol consumption, because it is a toxin that can cause cancer and damage organs such as the liver, pancreas and heart, even at low levels. Many people are willing to tolerate a little extra risk for the enjoyment of it, but most don’t fully appreciate how much risk they are taking on.
The Canadian Centre on Substance Use & Addiction has produced an excellent report detailing the precise odds of cancer and other illnesses at different levels of consumption. For some conditions, like mouth and throat cancer, the risk is already 1½ times higher at just two drinks a day.
A 2025 report on alcohol and cancer risk from the US surgeon general calculates that the total chance you’ll develop alcohol-related cancers over your lifetime increases with the amount you drink. It found that about five more women and three more men out of every 100 will develop cancer if they consume two standard alcoholic drinks a day, compared with those who have less than one drink a week.
Heavy drinking
In a 2024 global report on alcohol and health, the WHO estimated that a third of South African adults say they drink alcohol. But those who do drink consume a lot — an average of five drinks per day.
A study published in the South African Medical Journal in 2018 found that 43% of drinkers reported binge drinking, which the researchers defined as five or more drinks in one day. But, as they note, these numbers are likely even higher due to the stigma of reporting drinking habits.
Young people are at especially high risk. Using figures from the South African Demographic & Health Survey, I calculated that more than 80% of 15- to 34-year-old males who drink report that they drank more than five drinks in one day. The adolescent brain continues to develop until about the age of 25 and even if the drinking episodes are infrequent, binge drinking in young people can lead to long-term cognitive and psychological damage.
But it’s the immediate effects of any heavy drinking that are often most devastating — for both the individual and society.
In a global analysis of alcohol and risk of injuries, researchers found that after having four or five drinks, you’re at high risk of being either the cause or the victim of vehicle crashes, sexual or physical assault or murder.
Binge drinking in young people can lead to long-term cognitive and psychological damage
The risk curve for alcohol is exponential, meaning that the rate of harm increases with every drink. A multi-country study found that the risk of fatal traffic injury can almost double with every 0.02% — about one drink — increase in BAC. In the Western Cape, 45% of murder victims were found to have a BAC over 0.05%, suggesting that murder rates could be significantly reduced if heavy drinking were curtailed.
But every legal drink also contributes to jobs, tourism and taxes. In fact, according to a 2024 study published in the South African Journal of Economic & Management Sciences, if you disregard its harm, the liquor industry would contribute more than 2.5% to South Africa’s GDP — the value of everything a country produces and sells in a year. But the often overlooked point is that the net positive economic benefits occur at lower levels of consumption — higher levels cost the economy more than they generate.
Moderation
The findings present a dilemma for public health advocates in South Africa. On the one hand, we must inform the public that even one drink a day can have serious health consequences for an individual. On the other, drinking patterns here are so extreme that a call for such drastic reduction in drinking would be scoffed at.
While there is no doubt that heavy drinking is both bad for society and the economy, we don’t need to smash the liquor industry to combat heavy drinking. But we must intervene to optimise its social and economic benefits.
Based on the best international studies, here are three ways we can reduce heavy drinking:
- Limit alcohol advertising and promotion, which influences young people to drink heavily at a time when their brains are highly vulnerable. Advertising restrictions have been shown to work. It won’t be easy — especially as the industry uses on social media influencers — but it must be done.
- Close on-consumption liquor outlets (taverns and bars) at midnight, as required by the National Liquor Norms & Standards (2015). A modelling study commissioned by the DG Murray Trust, the organisation I lead, shows that, over 20 years, a midnight closure would reduce injuries and deaths by a factor of up to 15 compared with staying open until 2am.
- Introduce minimum unit pricing so that liquor cannot be sold at extremely low prices in poorer communities, which bear the brunt of heavy drinking. The National Treasury has made proposals in this regard and is reviewing submissions made by the public. Its involvement is significant because it gets to see both the income and expense side of the equation.
Inequality in South Africa is so severe that it’s hard to make a dent in the armour-proofed vehicles of violence — crime, toxic masculinity and the devaluation of human life. But we can starve them of their fuel, if our political leaders are informed and brave enough to act, to shift South Africa’s culture of heavy drinking to one of moderation.
David Harrison is a medical doctor and CEO at the DG Murray Trust, a public innovator based in Cape Town.
This story was produced by the Bhekisisa Centre for Health Journalism. Sign up for the newsletter.
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