21st September 2016 – People whose genetic profile makes them more susceptible to piling on the pounds respond equally well tolosing weight through better diet and more exercise as the rest of the population, says a study.
Article by Peter Rusell
Obesity is a major burden on public health and the public purse, and the problem is getting worse. A 2014 health survey for England found that 23% of adults were obese and 62% were either overweight or obese.
Weight loss strategies or genetic interventions?
With a growing incentive to find strategies to reverse the trend, some experts argue that diet, exercise and other weight-loss strategies are key to preventing and managing obesity while others say our genes largely determine our size.
Out of all the genes associated with body fatness, particular attention has been paid to one gene, known as FTO.
Reviewing the evidence
For the latest study in the BMJ an international team of researchers, led by Newcastle University, set out to assess the relation between the FTO gene and weight-loss interventions by analysing data from 8 randomised control trials involving 9,563 participants.
They found that at the start of each trial people with the FTO gene were slightly heavier, by an average of 0.89 kg, than those who did not carry the gene.
However, the scientists did not find that those who carried the gene were unable to lose weight. Indeed, they found that weight-loss strategies were just as effective in people with the so-called ‘fat gene’ as in everyone else. Also, these findings seem to apply to men and women, young and old and to people from differing ethnic backgrounds.
The authors acknowledge several limitations in their analysis. For instance, they only evaluated the effect of the FTO genotype when weight loss is known to be influenced by multiple genes. However, they say this is “an important finding for the development of effective weight loss interventions in the context of the global epidemic of obesity”.
‘Focus on improving lifestyle’
They conclude 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, says the causes of obesity are multiple and complex, but current evidence suggests they have little to do with gene profiles.
She argues that, if we are to defeat the obesity epidemic, a focus on personalised interventions based on the genome “may not pay off, at least in the short term”. Instead, she says “a rebalancing of research towards whole systems approaches including environmental drivers may be of greater benefit to the population in the long term”.