By JENNY HOPE
PUBLISHED: 02:48 EST, 5 September 2012 | UPDATED: 07:50 EST, 5 September 2012
People can be obese but metabolically healthy and fit, found an international study
Nearly half of fat people are just as healthy as slim people – and at no more risk of developing heart problems or cancer, researchers claim.
Doing exercise can offset the dangers of being obese, the researchers found.
The study – which is the largest of its kind – abolishes the notion that obesity automatically leads to ill-health.
It shows that some fat people manage to remain ‘metabolically healthy’ even though their body mass index would suggest they are not.
They have less risk of dying prematurely than unhealthy obese people and up to half the risk of developing or dying from heart disease or cancer.
Other research suggests that, among those with heart problems, those who are underweight or even normal weight are actually worse off than those who are fat.
Overweight and obese people should not fight the flab after having a heart attack because they are more likely to outlive their leaner counterparts, the new data says.
The controversial findings come as Britain grapples with an obesity epidemic, with almost a quarter of Britons classified as obese and around half overweight.
But an international study of 43,265 people shows people can be obese but metabolically healthy and fit, with as much chance of keeping cardiovascular disease and cancer at bay as normal weight people.
Obese people who are metabolically healthy don’t suffer from conditions such as insulin resistance, diabetes and high cholesterol or blood pressure and are fitter, as measured by how well the heart and lungs perform, than other obese people.
The new study, which recruited Americans between 1979 and 2003 who underwent fitness tests, found 46 per cent of the obese recruits were metabolically healthy.
They had a 38 per cent lower risk of death from any cause than their metabolically unhealthy obese peers, and the same risk as healthy, normal weight participants.
The risk of developing or dying from heart disease or cancer was reduced by between 30-50 per cent for metabolically healthy, obese people, compared with fat unhealthy people, and was similar to those of normal weight.
Study leader Dr Francisco Ortega said ‘It is well known that obesity is linked to a large number of chronic disease such as cardiovascular problems and cancer.
‘However, there appears to be a sub-set of obese people who seem to be protected from obesity-related metabolic complications.
‘Our study suggests that metabolically healthy but obese people have a better fitness level than the rest of obese individuals.
‘We believe that getting more exercise broadly and positively influences major body systems and organs and consequently contributes to make someone metabolically healthier, including obese people.
‘In our study, we measure fitness, which is largely influenced by exercise.’
Fat but fit? Dr Ortega said not all obese people have the same prognosis
Dr Ortega is a research associate at the Department of Physical Activity and Sport, University of Granada, Spain), and at the Karolinska Institute in Sweden, but the investigation took place at the University of South Carolina, USA.
Dr Ortega said ‘Physicians should take into consideration that not all obese people have the same prognosis. Physician could assess fitness, fatness and metabolic markers to do a better estimation of the risk of cardiovascular disease and cancer of obese patients.
‘Our data support the idea that interventions might be more urgently needed in metabolically unhealthy and unfit obese people, since they are at a higher risk. This research highlights once again the important role of physical fitness as a health marker.’
The findings are published online today in the European Heart Journal.
A second study which analysed data from 64,000 heart patients in Sweden provides new evidence supporting the ‘obesity paradox’, which means fat patients with heart disease have ‘paradoxically’ better outcomes and survival than thinner patients.
The greatest risk of dying was among the underweight and morbidly obese, who have the very highest levels of obesity.
The lowest risk of death was found among overweight and obese patients, said researcher Dr Oskar Angerås, consultant cardiologist at the Sahlgrenska Academy, University of Gothenburg.
He said it was well known that maintaining a healthy weight could help avoid heart problems.
But advice to overweight and obese patients who have already developed heart problems to lose weight was wide of the mark as it might have a ‘negative effect’.
Excess weight may help because patients have more reserves to fight chronic disease than thinner patients.
Amy Thompson, Senior Cardiac Nurse at the British Heart Foundation (BHF), said: ‘In the majority of cases, obesity is an undeniable risk factor for developing coronary heart disease. However, these studies remind us that it is not always your weight that’s important, but where you carry fat and also how it affects your health and fitness.
‘It is particularly important to be aware of your weight if you are carrying excess fat around your middle. The fat cells here are really active, producing toxic substances that cause damage which can lead to heart disease. Maintaining a healthy diet with lots of physical activity can help to slim you down as well as reduce your risk of heart health problems.’