Health: ‘Fat but fit’ people still at risk of health issues, study warns

Obese people who exercise regularly are still at an increased risk of diabetes, heart disease, stroke and respiratory disease, a study has cautioned.

University of Glasgow experts studied people who were obese but had a normal metabolic profile, a combination dubbed ‘metabolically healthy obesity’ (MHO). 

Individuals with MHO have a body mass index of 30 or higher, but lack the systemic inflammation, problematic blood fats and insulin issues often seen with obesity. 

Experts have calculated that MHO may occur in the general population at levels of anywhere between 3 and 22 per cent.

The team found that metabolically healthy obesity increases the risk of various health issues in comparison with people of a regular BMI.

For example, it raises the risk of type 2 diabetes 4.3 fold and leads to a whopping 76 per cent increase in the risk of heart failure.

Experts estimated that there are more then 300 million people worldwide who are obese — a figure expected to exceed 1 billion, or 1-in-5 people, come the year 2030.

Obese people who exercise regularly are still at an increased risk of diabetes, heart disease, stroke and respiratory disease, a study has cautioned (stock image)

The study was undertaken by epidemiologist Frederick Ho of the University of Glasgow and his colleagues.

‘People with metabolically healthy obesity are not “healthy” as they are at higher risk of heart attack and stroke, heart failure, and respiratory diseases compared with people without obesity who have a normal metabolic profile,’ they wrote.

‘Weight management could be beneficial to all people with obesity irrespective of their metabolic profile.’

‘The term “metabolically healthy obesity” should be avoided in clinical medicine as it is misleading, and different strategies for defining risk should be explored.’ 

In their study, the researchers monitored 381,363 individuals — all of whom were either of a healthy weight, overweight or obese.

All the participants were part of the UK Biobank project, a large-scale study that collected detailed genetic and health information on half-a-million volunteers.

Subject were grouped into one of four categories — either metabolically healthy obese (MHO), metabolically unhealthy obese (MUO), metabolically healthy non-obese (MHN) or metabolically unhealthy non-obese (MUN).

The team found that the MHO individuals in the study were generally younger in age, watched less television, were more educated, at more red and processed meat and were less likely to be male and non-white than MUO participants.

Furthermore, MHO subjects were 4.3 times more likely to have type 2 diabetes, 18 per cent more at risk of a heart attack or stroke and 76 per cent more likely to suffer heart failure than metabolically healthy participants without obesity.

Metabolically healthy obesity also came with a 28 per cent increase in the risk of respiratory disease and a 19 percent increase in the likelihood of suffering from chronic obstructive pulmonary disease.

When compared with metabolically unhealthy people without obesity, those classed as MHO were also 28 per cent more likely to experience heart failure.

‘Generally, rates of cardiovascular and respiratory outcomes were highest in MUO, followed by MUN and MHO, except for incident and fatal heart failure, and incident respiratory diseases,’ the researchers noted.

‘For these outcomes, people with MHO had higher rates than those with MUN.”

‘People with metabolically healthy obesity were at a substantially higher risk of diabetes, heart attack and stroke, heart failure, respiratory diseases, and all-cause mortality compared with [MHN people].’ 

‘Particularly worth noting is that people with metabolically healthy obesity had a higher risk of heart failure and respiratory disease than metabolically unhealthy participants without obesity.’

In addition, the team found that — in a subset of participants they followed up with — one third of the originally MHO individuals became metabolically unhealthy within 3–5 years.  

The full findings of the study were published in the Diabetologia, the journal of the European Association for the Study of Diabetes. 


Obesity is defined as an adult having a BMI of 30 or over.

A healthy person’s BMI – calculated by dividing weight in kg by height in metres, and the answer by the height again – is between 18.5 and 24.9. 

Among children, obesity is defined as being in the 95th percentile.

Percentiles compare youngsters to others their same age. 

For example, if a three-month-old is in the 40th percentile for weight, that means that 40 per cent of three-month-olds weigh the same or less than that baby.

Around 58 per cent of women and 68 per cent of men in the UK are overweight or obese. 

The condition costs the NHS around £6.1billion, out of its approximate £124.7 billion budget, every year.

This is due to obesity increasing a person’s risk of a number of life-threatening conditions.

Such conditions include type 2 diabetes, which can cause kidney disease, blindness and even limb amputations.

Research suggests that at least one in six hospital beds in the UK are taken up by a diabetes patient.

Obesity also raises the risk of heart disease, which kills 315,000 people every year in the UK – making it the number one cause of death.

Carrying dangerous amounts of weight has also been linked to 12 different cancers. 

This includes breast, which affects one in eight women at some point in their lives.

Among children, research suggests that 70 per cent of obese youngsters have high blood pressure or raised cholesterol, which puts them at risk of heart disease.

Obese children are also significantly more likely to become obese adults. 

And if children are overweight, their obesity in adulthood is often more severe.  

As many as one in five children start school in the UK being overweight or obese, which rises to one in three by the time they turn 10.