Having a gene associated with obesity - sometimes referred to as the “fat gene” - does not affect a person’s ability to lose weight, new research has found.
The scientists stressed that obesity is a major public health burden and its prevalence is increasing worldwide.
With an estimated 2.1 billion adults now overweight or obese, researchers said there is an urgent need to develop more effective strategies for preventing and managing obesity.
In recent years there has been debate around whether genetic makeup makes a difference to weight.
Some experts argue that genes play a significant role in the development of obesity, while others say that changes in our environment are responsible for increasing obesity.
In reality, the extent to which genes determine the ability to lose weight remains unclear.
For this reason, an international team of researchers set out to test the relation between the FTO gene and weight loss interventions using data from almost 10,000 participants in eight randomised control trials.
Participants with the FTO gene were found to be slightly heavier (0.89 kg) than those not carrying the gene at the start of the trials.
However, the researchers found no relation between FTO and the ability to lose weight.
Changes in body mass index, body weight, and waist circumference by FTO genotype did not differ by intervention type, intervention length, ethnicity, sample size, sex, or baseline body mass index and age category.
The authors acknowledged several limitations in their analysis, but said this is “an important finding for the development of effective weight loss interventions in the context of the global epidemic of obesity”.
They concluded that future strategies for managing obesity “should focus on improving lifestyle behaviours, principally eating patterns and physical activity, since these will be effective in achieving sustained weight loss irrespective of FTO genotype”.
In a linked editorial, Dr Alison Tedstone, chief nutritionist at Public Health England, said the causes of the obesity epidemic are multiple and complex, but current evidence suggests they have little to do with gene profiles.
She argued that, if we are to turn back the tide of obesity, a focus on personalised interventions based on genes “may not pay off, at least in the short term”.
Instead, she recommended “a rebalancing of research towards whole systems approaches including environmental drivers may be of greater benefit to the population in the long term”.