Current NHS guidelines make a clear distinction between the recommended daily calorie intake between the sexes – 2,500 for men and 2,000 for women – based on the thinking that men have more muscle mass and therefore a faster metabolism.

In reality, our recommended daily calorie intake varies according to factors like weight, age and activity levels and a study published in 2021 in the journal Science found no difference between male and female metabolisms. 

But science tells us there are variations in how men’s and women’s bodies process and metabolise certain types of food. “Differences between the sexes and how nutrition affects them can vary by things like metabolism, sex hormones and body structures,” says the registered dietitian Helen Bond. Here, we look at how…

Women process alcohol differently

“When it comes to the health impact of alcohol, it’s not just how much you drink but how your body processes it,” says Dr Emma Catterall, the research and evidence lead at the charity Drinkaware. “Men process it more efficiently than women because of their different body compositions, even when they’re a similar weight. Women have a higher body fat percentage and are composed of less water.”

This means women reach a higher blood alcohol content more quickly, even after drinking the same amount as a man, says Catterall. “They also tend to be smaller than men, and have lower levels of an enzyme that metabolises alcohol – called alcohol dehydrogenase (ADH) – so they absorb alcohol into their bloodstream much more quickly.”

Despite these differences, in 2016, the NHS  updated its guidelines to state that men and women who drink regularly should drink no more than 14 units of alcohol over a week (previously, a man’s limit was 21 units).

“Even though men metabolise alcohol more efficiently, it doesn’t give them a free pass to drink more,” says Dr Catterall, adding that the health risks to both sexes are still significant, and include certain cancers, heart and liver disease, an increased risk of mental health problems and damage to the nervous system. “Women are more susceptible to the longer term health implications,” says Dr Catterall. “With liver disease for example, the threshold for risk is much lower in women and they’re also more likely to have rapid development of the disease. They’re also at a higher risk of cardiomyopathy, a cardiac disease caused by chronic alcohol consumption, while they’re more likely than men to suffer alcohol-induced anxiety and depression, even when drinking the same amount.”

However, Dr Catterall says men still outnumber women in alcohol-related diseases largely because they drink more often and more heavily. “For advice on cutting down, take the quick and free Drinking Check quiz on our website,” she says.

Sugary drinks hit men harder

Studies have long found that women are more susceptible to a sweet tooth than men. Which is just as well given new research published this month that found fizzy drinks are more likely to cause boys to go on and develop diabetes than girls. Researchers from Harvard University found that sugary drinks had over three times the impact on boys’ insulin resistance and blood glucose levels (risk factors for diabetes), than it did for girls.

It follows a study from the University of Missouri published in 2022 that found lifestyle risk factors for diabetes, such as reduced physical activity and increased sugar intake, hit men harder than women. After 10 days, the male participants had reduced blood flow in the legs, and lower levels of the hormone adropin, which plays a health-protective role in regulating insulin sensitivity and body weight.

Men are more likely to develop type 2 diabetes even when they’re at a comparably lower weight than women, says Roy Taylor, the professor of medicine and metabolism at Newcastle University and author of Your Simple Guide to Reversing Type 2 Diabetes. “They also develop the disease at a lower age on average. However, if women get type 2 diabetes their heart disease risk rises more than for men,” he says.

A high-fat diet impacts males more 

When it comes to high-fat foods, like burgers, steak and cheese, male and female brains respond differently, say researchers from Cedars-Sinai Diabetes and Obesity Research Institute. That, in turn, impacts the risk of heart disease.

“For the first time, we have identified remarkable differences in the sexes when it comes to how the body responds to high-fat diets,” says Prof Deborah Clegg, who led the research. Her team found that male brains are more likely to become inflamed and hearts damaged when given a high-fat diet. According to studies, brain inflammation is linked to overeating and changes in blood sugar levels and obesity risk. 

During the research, Prof Clegg said her team discovered clues that led them to believe, “it is as if the brains of females had a chemical force field that kept the dangers of fats and sugars from harming them. Our data in this study also adds to the growing body of evidence that brain inflammation may be a key factor in the obesity epidemic. These negative brain changes can occur even over a short period of eating fatty and sugary food and clearly affected males much more than females.”

Men get more from dark chocolate

The health benefits of dark chocolate, which contains a minimum of 70 per cent cocoa, over milk chocolate (which typically contains between 10 and 20 per cent), include reducing the risk of heart disease, and being rich in iron, magnesium and zinc. Men seem to respond to the nutritional content better than women. 

The quality of men’s blood improved far more than women’s after eating chocolate with at least 70 per cent cocoa, say researchers from Aberdeen University. It could help reduce their risk of stroke. “Men’s platelets [cells in blood which can clump together to form clots] are significantly better behaved than women’s after eating dark chocolate, as they don’t seem to clump together as much and are far less stressed,” said the study author Dr Baukje de Roos. “It’s a bit of a mystery why this is. It might be to do with hormones but it’s something we’re still trying to understand.”

White pasta and the menopause

The topic of carbs is an often debated one but Helen Bond says carbohydrates are a key part of a healthy, balanced diet. “Alongside fat and protein, they’re one of the three macronutrients, in other words the cornerstones, of our diets. We need them for energy and, as well as being found in bread and pasta, they’re found in plant foods like fruits, vegetables, nuts, seeds and legumes, such as beans and lentils.”

However, a diet high in refined carbs, such as white bread, rice and pasta, may increase the risk of low mood depression in postmenopausal women according to a study from Columbia University Medical Center in the United States. Researchers there found these foods triggered a hormonal response in the body to reduce blood sugar levels, which can worsen mood and increase fatigue among women.