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


Obese people who exercise regularly are still at increased risk for diabetes, heart disease, stroke and respiratory disease, a study warns.

Experts from the University of Glasgow studied people who were obese but had a normal metabolic profile, a combination called “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 problems commonly seen with obesity.

Experts have calculated that MHO can occur in the general population at levels between 3 and 22 percent.

The team found that metabolically healthy obesity increases the risk of several health problems compared to people of normal BMI.

For example, it increases the risk of type 2 diabetes 4.3 times and leads to a whopping 76 percent increase in heart failure risk.

Experts estimate that there are more than 300 million people worldwide who are obese — a figure projected to exceed 1 billion, or 1 in 5 people, by the year 2030.

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

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

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

“People with metabolically healthy obesity are not ‘healthy’ because they have a higher risk of heart attack and stroke, heart failure and respiratory disease compared to non-obese people who have a normal metabolic profile,” they wrote.

“Weight management can be beneficial for all obese people, regardless of their metabolic profile.”

“The term ‘metabolically healthy obesity’ should be avoided in clinical medicine because it is misleading, and different strategies should be explored to define risks.”

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

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

The subjects were grouped into one of four categories – either metabolically healthy obesity (MHO), metabolically unhealthy obesity (MUO), metabolically healthy non-obese (MHN), or metabolically unhealthy non-obese (MUN).

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

In addition, MHO subjects were 4.3 times more likely to have type 2 diabetes, 18 percent more risk of heart attack or stroke, and 76 percent more likely to have heart failure than metabolically healthy participants without obesity.

Metabolic healthy obesity was also associated with a 28 percent increase in the risk of respiratory disease and a 19 percent increase in the risk of chronic obstructive pulmonary disease.

Compared to metabolically unhealthy people without obesity, those classified as MHO were also 28 percent more likely to have heart failure.

“Overall, cardiovascular and respiratory outcomes were highest in MUO, followed by MUN and MHO, except for incident and fatal heart failure and incident respiratory disease,” the researchers noted.

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

People with metabolically healthy obesity had a significantly higher risk of diabetes, heart attacks and strokes, heart failure, respiratory disease and all-cause death compared to [MHN people].’

“Of particular note 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 – a third of original MHO individuals became metabolically unhealthy within 3-5 years.

The full findings of the study have been published in the Diabetology, the journal of the European Association for the Study of Diabetes.


Obesity is defined as an adult with a BMI of 30 or higher.

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

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

Percentiles compare young people with others of the same age.

For example, if a three-month-old child is in the 40th percentile for weight, that means 40 percent of the three-month-old weighs the same or less than that baby.

About 58 percent of women and 68 percent of men in the UK are overweight or obese.

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

This is because obesity increases the 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 is occupied by a diabetic.

Obesity also increases the risk of heart disease, which kills 315,000 people in the UK every year – making it the leading 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.

In children, research suggests that 70 percent of obese youth have high blood pressure or elevated cholesterol, which puts them at risk for 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 in the UK attend school who are overweight or obese, rising to one in three by the time they turn 10.