The idea of "healthy obesity" is a myth, research suggests.

Excess fat still carries health risks even when cholesterol, blood pressure and sugar levels are normal, according to a study of more than 60,000 people.

It has been argued that being overweight does not necessarily imply health risks if individuals remain healthy in other ways.

The research, published in Annals of Internal Medicine, contradicts this idea.

Researchers from the Mount Sinai Hospital, Toronto, found there was no healthy pattern of increased weight when heart health was monitored for more than 10 years.

They argue that people who are metabolically healthy but overweight probably have underlying risk factors that worsen over time.

Study leader Dr Ravi Retnakaran told BBC News: "This really casts doubt on the existence of healthy obesity.

"This data is suggesting that both patients who are obese who are metabolically unhealthy and patients who are obese who are metabolically healthy are both at increased risk of death from cardiovascular disease, such that benign obesity may indeed be a myth."

Heart risk

The British Heart Foundation says obesity is a known risk factor for heart disease and the research shows there is no healthy level of obesity.

Senior cardiac nurse, Doireann Maddock, said: "So, even if your blood pressure, cholesterol and blood sugar levels are normal, being obese can still put your heart at risk."

She said it was useful to think of lifestyle overall rather than individual risk factors.

"As well as watching your weight, if you stop smoking, get regular physical activity and keep your blood pressure and cholesterol levels at a healthy level, you can make a real difference in reducing your risk of heart disease.

"If you are concerned about your weight and want to know more about the changes you should make, visit your GP to talk it through."

The study looked at findings from more than 1,000 published studies.