Obesity Gene

Makes kids eat more

Biology News

Image: Robert Lawton

An obesity gene variant, present in 63 percent of the population, makes children eat an average of one hundred extra calories per meal, says a new study.

A team at the University of Dundee conducted an eating test with 100 schoolchildren aged between 4 and 10 and found that the children with the common variant of the so-called obesity gene FTO consumed an extra 100 calories. These children chose to eat food types that contained more sugar and fats as opposed to more healthy options.

Results of the study are published in the New England Journal of Medicine. The research was led by Professor Colin Palmer at the University of Dundee, and included colleagues who are now based at the Universities of St. Andrews, Brighton and Glasgow Caledonian.

The study measured the metabolism, fat distribution, exercise and eating behaviors in the schoolchildren. They were given a test meal at school, which included a mix of options: ham, cheese, crackers, crisps, raisins, grapes, cucumber, carrot, chocolate buttons, water, orange juice and bread rolls. Investigators recorded the food that remained on each child’s tray.

Researchers found the gene had no impact on metabolic rates or measures of physical activity. There was also no evidence that individuals carrying the obesity gene had any problem knowing when to stop eating. However, they did find that there was an increased calorie intake from higher consumption of fattening foods.

"This work demonstrates that this gene does not lead to obesity without overeating and suggests that obesity linked to this gene could be modulated by careful dietary control," said Palmer, Chair of Pharmacogenomics in the Biomedical Research Institute at the University of Dundee. Palmer went on to say that,

What it effectively shows is that the people with the relevant variants on the gene have a trait which may lead them to eat more unhealthy, fattening foods. I would stress that this is a trait, and not an absolute occurrence.

The findings do not change the dietary and lifestyle advice to people, which would be to eat relatively healthily and take regular exercise. Doing this will still have a positive effect whether you carry this gene variant or not.

But these findings do also reinforce the hypothesis that the increase in obesity seen in children over recent years may be largely attributable to the widespread availability of inexpensive and highly energy dense foods, which may be more attractive to the large proportion of the population who carry this genetic variant.

The study's results are also consistent with findings in animals that have shown feeding and fasting turn the expression of this gene on and off in the regions of the brain known to control eating behaviors.

Palmer was part of a large group of scientists from around the UK that discovered the obesity gene, FTO, in 2007. They found that individuals carrying one copy of the variant (49% of the population) have an approximately 30% increased risk of obesity and individuals carrying two copies of the variant (14% of the population) have almost 70% increased risk. This effect has since been confirmed in many populations around the world.