No link between "obesity gene" and intentional weight loss
“This indicates that even in people at genetic risk of obesity, lifestyle change is an effective way to lose weight”, says Professor Paul Franks of Lund University in Sweden, one of the researchers responsible for the study.
Among other factors, variations in one of our genes, including FTO, explain why some people are more prone to developing obesity than others. But less is known about how genetics influences weight loss. Therefore, in the new study, researchers investigated the possible significance of variations in the FTO gene for the amount of weight the participants lost with the help of diet, physical exercise or drugs.
By examining data from eight existing intervention studies, with a total of 10 000 participants from North and South America and Europe, the researchers compared weight loss in carriers of a particular variant of the FTO gene, which increases the risk of obesity, to that of people who were not carriers of the risk variant. At the outset, carriers of the risk variant weighed on average one kilo more than participants who were not carriers.
The findings showed that the different FTO variants did not affect the participants’ capacity to lose weight. The researchers found that the changes in BMI or waist measurements according to FTO genotype did not differ by intervention (diet, exercise, drugs) or by ethnicity, gender, age and participants’ BMI from the outset.
“The study is important as the FTO gene is one of only a few genes which seem to affect the relationship between physical activity and body weight. Several major population studies have previously indicated that carriers of the risk variant may not get the same benefit from physical activity in everyday life as people without the risk variant in the general population”, says Paul Franks, who led one of the largest clinical studies included in the new meta-analysis. He continues:
“For the first time, this study presents data from several carefully conducted large intervention studies. In contrast to what the major population studies indicated, these intervention studies show that people who carry the risk variant of the FTO gene lose weight like everyone else, when they take part in structured lifestyle interventions.”
The findings are published in the research journal The BMJ (formerly British Medical Journal).