Being overweight may not be as risky for your health as we’re so often told. Indeed you might be no worse in terms of heart health than skinny people.
Provided your waist is slim, that is.
But it’s bad news for people who aren’t overweight, yet have a larger waist – this can increase their heart disease risk by up to 50 per cent.
That’s the surprising suggestion from a new US study.
For years a healthy weight has been determined by your body mass index (also known as your BMI), calculated by dividing your weight in kilograms by height in metres squared.
But increasingly it’s been recognised that having a round middle can increase your risk of heart disease and other serious conditions, with the NHS saying your waist should measure less than half your height.
Now a new study, published in the Journal of the American College of Cardiology, provides further evidence of the importance of waist size.
Researchers, from Johns Hopkins University in the US, analysed data from 260,000 people over 20 years, tracking their rate of heart attacks, strokes and heart failure.
For people who aren’t overweight, yet have a larger waist, their risk of heart disease can increase by up to 50 per cent, a new study suggests
They found that people with an ‘obese’ BMI (30 or more) but who had a relatively small waist didn’t have significantly higher cardiovascular risks than people with a healthy BMI (18.5 to 24.9) and low waist measurements.
The most at-risk group were those with a normal BMI but a large waist.
The problem with a larger waistline is that it indicates that a dangerous type of fat, visceral fat, is starting to accumulate in and around vital organs, explains Naveed Sattar, a professor of cardiometabolic medicine at the University of Glasgow.
This visceral fat triggers several mechanisms in the liver that contribute to an increased risk of heart disease.
Professor Sattar explains: ‘Excess fat in the liver screws up your sugar metabolism and increases your risk of diabetes [a major risk factor for heart disease].’
It does this by interfering with the body’s ability to respond to the hormone insulin, which clears excess sugar from the bloodstream – this leads to insulin resistance and poorly controlled blood sugar levels, which can damage blood vessels over time.
‘When the liver has excess fat, it also releases more of a harmful fat called triglycerides, into the blood,’ he told the Daily Mail.
‘Researchers now believe higher triglyceride levels also accelerate heart disease over time.’
Belly fat is also linked to higher blood pressure, although it’s not known exactly why.
‘The problems caused by a build-up of visceral fat – such as fatty liver, high cholesterol and high blood pressure – can then start to feed into each other,’ says Dr Mayoni Gooneratne, a former NHS colorectal surgeon and medical director at Personalised Health Clinics.
‘When you develop several of these problems at the same time, we call this metabolic syndrome, which is associated with a much higher risk of heart disease, stroke and type 2 diabetes.’
While older men for example are more prone to storing fat around their belly – partly due to a fall in the hormone testosterone which alters fat distribution – anyone can develop it, says Professor Sattar.
Professor Naveed Sattar says the problem with a larger waistline is that it indicates that a dangerous type of fat, visceral fat, is starting to accumulate in and around vital organs
But if belly fat is so dangerous, what can you do to get rid of it?
The good news is that visceral fat is very responsive to weight-loss programmes.
Nader Silver, a preventive cardiology fellow at Johns Hopkins University, who led the new research, says losing just 5 per cent of body weight makes a difference.
The more you lose the greater the benefit, he says.
This echoes research published in 2020 by Roy Taylor, an emeritus professor of medicine and metabolism at Newcastle University, which found just 10 to 15 per cent weight loss could put some people into remission from type 2 diabetes.
High-intensity exercise (such as sprinting, followed by periods of lower intensity such as walking), is one of the most effective ways to shed excess pounds – followed by running, fast swimming, skipping or tennis, according to a 2024 review of studies involving almost 5,000 overweight or obese people, published in Obesity Reviews.
‘High-intensity interval training places a substantial energy demand on working muscles, increasing their uptake of glucose from the bloodstream,’ explains Dr Gooneratne.
And it helps to train your muscles to burn fat for energy more easily and efficiently.
But you don’t necessarily have to exhaust yourself to reap rewards.
A combination of moderate intensity exercise – such as brisk walking – and HIIT is also effective in reducing visceral fat, reported the International Journal of Obesity in 2021.
The best results came from three 30 to 60 minute sessions each week.
Muscle-strengthening exercises are also useful – aim for two sessions a week – because muscles use glucose for energy, so the more muscle you build the more glucose you can take up from your bloodstream.
This in turn helps to regulate your blood sugar levels, reducing your cardiovascular risk, says Dr Gooneratne.
Diet-wise, the best evidence is for eating a predominantly plant-based Mediterranean-style diet – rich in vegetables, legumes (chickpeas, lentils, beans), wholegrains, nuts, seeds and olive oil, along with moderate amounts of oily fish (such as salmon or mackerel; at least two portions a week), meat and dairy.
A 2022 trial published in the journal BMC Medicine found this kind of diet produced a greater reduction in visceral fat than standard healthy-eating guidance.
Participants who followed a ‘Green’ Mediterranean diet (essentially a Mediterranean diet with even more plant foods and less red or processed meat, plus walnuts and green tea every day) lost 14.1 per cent of their visceral fat – even though overall body fat dropped just 3.9 per cent.
Those following general healthy guidelines lost only 4.2 to 6 per cent of their visceral fat.
Researchers think the benefits stem from high levels of fibre and powerful plant compounds that reduce disease-causing inflammation in the body.
Research shows that avoiding or drastically cutting back on other foods is also vital.
These include sugary drinks, refined carbohydrates (such as breakfast cereals, pastries, white bread, biscuits and pies), ultra-processed foods, processed meats and excess saturated fat, which is associated with insulin resistance and greater abdominal fat accumulation.
Cutting back on alcohol can also make a big difference.
Melanie Murphy Richter, a dietitian at L-Nutra Health, which runs medical nutrition programmes, says there is scientific logic behind the term ‘beer belly’.
‘Alcohol contains seven calories per gram, so it can add a significant amount of energy without providing much fullness.
‘Many alcoholic drinks also contain sugar, and alcohol can lower our inhibitions around food, making larger portions or late-night eating more likely.’
In addition, the body prioritises processing and expelling alcohol, a toxin, temporarily slowing the burning of fat.
Frequent alcohol consumption can also raise the level of harmful triglycerides, thereby contributing to the build-up of fat in the liver.
The good news is that belly fat responds rapidly to these strategies even before you see changes in your body.
As Melanie Murphy Richter explains: ‘In some people visceral fat may begin decreasing before the visible, pinchable fat around the stomach changes dramatically – so metabolic health may be improving before someone sees the exact aesthetic change they were hoping for.’
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