What drinking beer really does to your body – and the healthiest options for a pint

How does beer affect sleep?

 Beer, and more precisely the alcohol in it, is paradoxically a sedative that disrupts sleep. It relaxes initially but when the sedative effects wear off, typically after three or four hours, several processes then disrupt sleep.

It relaxes the muscles and tissues in the soft palate, throat and back of the tongue, leading to increased snoring and sleep apnoea. The volume of liquid consumed by heavy beer drinkers will also generally lead to more trips to the toilet during the night.

Drinkers can also experience withdrawal symptoms as the effects of the alcohol wears off. One study suggests that men are more affected than women. The 2015 research showed ‘significant correlations’ between alcohol use and sleep quality, sleep duration, and sleep disturbances in men.

Prof Marlow explains that excessive alcohol consumption can also have significant psychological impacts during the night.

“People talk about experiencing fear and anxiety and dread that comes in the wee small hours,” she says. “Alcohol can amplify negative emotions.”

How does beer affect weight?

Typically a beer belly is a tight, solid, bulging stomach, where the excess fat is stored in the body cavity around the internal organs as visceral fat. This body shape is linked to an increased risk of heart attack, stroke, diabetes, and several cancers because visceral fat also causes inflammation.  

Despite the name, beer is not specifically responsible for its namesake belly, with one 2003 study in the Czech Republic even concluding that ‘it is unlikely that beer intake is associated with a largely increased waist to hip ratio or BMI’.

However, beer is packed with calories and excess calories are stored as fat.

Duane Mellor, dietitian, and spokesperson for the British Dietetic Association (BDA) says: “Depending on the strength, beer can be anything from 170 to 300 calories per pint. A pint of Guinness 4% ABV is 200 calories with about four and a half teaspoons of sugar in it. A pint of 5% bitter has around 17g and 240 calories. Pilsners are lower as they tend to brew out the sugars.

“Beer is fat free, but that’s irrelevant because our bodies aren’t great at regulating liquid calories and those extra calories, if they’re not used, get laid down as fat somewhere.”

Even low alcohol beers can still contain around 12g of sugar per pint.

“So four pints of low alcohol beer will still reach your recommended daily amount of free sugar, and that’s before you start eating,” adds Mellor.

 Four pints of beer topped off with an Indian meal of chicken tikka masala, pilau rice, naan bread and onion bhaji, high saturated fats, can easily add up to over 2,000 calories.

How does beer affect digestion?

Alcohol is an irritant which can cause inflammation of the lining of the stomach. There is also evidence that alcohol can disrupt the gut biome.

However, in recent years some research suggests that certain beers could help improve the diversity of species in the gut microbiome, something which tends to be associated with health benefits. A 2022 study in the Journal of Agricultural and Food Chemistry followed 22 men who drank a little more than half a pint of beer every day for four weeks and found that they subsequently had better markers of intestinal health.

How does beer affect hydration?

Alcohol is a diuretic, which means it exacerbates water loss through urine. It does this by inhibiting the production of a hormone called vasopressin, which plays a large role in the regulation of water excretion. Therefore, if you do not drink enough water, but consume large amounts of alcohol, you are likely to become dehydrated.

There is a caveat, however. Some experts believe that as beer contains some electrolytes and has a high water content, it can be useful for hydration if it is low alcohol or alcohol free. Indeed, one 2015 study into the effects of a moderate intake of beer on hydration after exercise in the heat concluded that a moderate beer intake ‘has no deleterious effects on markers of hydration in active individuals’.

Regular beer consumption and chronic conditions

Studies consistently link alcohol consumption with the development of several chronic disorders, such as cancer, cardiovascular diseases, diabetes and obesity. Light to moderate drinking tends to lower risks of certain diseases, while heavy drinking tends to increase the risks. Genes, hormones and lifestyle factors such as smoking and diet can modify the association. Alcohol strength by volume is the determining factor in most cases, and beverage types could also have an influence.  

A 2016 review of research into the links between alcohol and chronic diseases identified ‘significantly higher risks for cancer, cardiovascular diseases, diabetes and obesity’ for heavy drinkers’.

Good news for beer drinkers?

While experts agree that there are no health benefits to alcohol, drinking low to moderate amounts of lower alcohol beer, two or three days a week with several days non-drinking in between is generally safe.

Prof Nutt explains: “Beer drinkers seem to have less harm for the same intake of alcohol than wine or spirit drinkers. This is probably because beer has vitamins and other relatively healthy things in it, whereas vodka has got nothing healthy in it at all, and wine has got less of those healthy compounds. It might also be that you can’t really binge on beer because of the volume of liquid.”

Beer has been linked to improved bone density although Mellor explains that this might be because beer drinkers tend to be heavier, “so loading on the bones will increase bone density”.

Brewed and fermented products contain beneficial bioactive compounds, which theoretically might be good for gut health, adds Mellor. “But you need to watch the alcohol content because you could undo all the benefits.”

Interestingly, for this reason one brand of German wheat beer, Erdinger, markets its alcohol free variety as a sports drink as it contains electrolytes, modest sugar, folic acid and vitamin B12.

Meanwhile, a 2015 study reported that light to moderate beer drinking (12.5–25 g/day) could improve the function of blood vessels because of the beneficial compounds found in beer.

A study looking at various animal and human experiments acknowledges that purported health benefits of alcohol “are controversial”, but says sensible consumption has a “positive effect on the regulation of human immune function”.

Price and quality of beer bear no relation to whether it is better or worse for you, as Marlow explains.

“The bottom line is the volume of alcohol. People may tell themselves that it’s okay, they’re drinking a craft beer. It’ll be fine. But lots of those craft beers have high alcohol volume as well.”