'Healthy fat but fit' heart disease risk
15th August 2017 – A new study adds to the growing evidence that the possibility of being 'fat but fit' is nothing more than a myth, with results showing that carrying extra weight can increase the risk of a heart attack in otherwise healthy people.
Previous studies have suggested there is a subset of overweight people who appear to lack the adverse health effects of excess weight. They have been classed as 'metabolically healthy obese' in the medical community but as 'fat but fit' in the media. However, the current study, published in the European Heart Journal, has dispelled this myth.
Researchers have found that being overweight or obese increases a person's risk of coronary heart disease by up to 28% – even if they are metabolically healthy – when compared to those with a healthy body weight. Their findings suggest that even apparently "healthy" people should aim to maintain normal body weight that is within a healthy range.
Coronary heart disease (CHD) occurs when not enough blood gets to the heart due to clogged arteries, which can lead to heart attacks. According to the British Heart Foundation, CHD is responsible for nearly 70,000 deaths every year in the UK. There are 2.3 million people in the UK living with CHD.
Professor Metin Avkiran, associate medical director at the British Heart Foundation, which part-funded the research, points out in a statement: "Coronary heart disease – the cause of heart attacks and angina – is the UK's single biggest killer. But there are steps you can take to lower your risk."
European follow-up study
In the largest study of its kind, a group led by researchers at Imperial College London (ICL) and the University of Cambridge have shown that otherwise healthy overweight people are still at increased risk of CHD when compared to people with a healthy weight. Scientists used data from the European Prospective Investigation into Cancer and Nutrition (EPIC) for their study.
They included more than half a million people from 10 European countries. After a follow-up period of more than 12 years, 7,637 people in the EPIC cohort experienced CHD events, including death from heart attack.
Categorising the participants
Using definitions from the World Health Organization (WHO), the researchers classified participants based on their body mass index (BMI), calculated as weight (kg) divided by the square of their height (m):
- Obese – a BMI of 30 or more
- Overweight – a BMI of 25 to less than 30
- Normal weight – a BMI between 18.5 and less than 25
A larger proportion of the control group – 63% – were women, with an average age of 53.6 years old and an average BMI of 26.1.
The participants were also categorised as 'unhealthy' if they had three or more of a number of metabolic markers, including:
The researchers adjusted the data to take into account lifestyle factors such as diet, exercise, smoking and socioeconomic status.