A person’s genes can influence whether they are fat or thin, with the odds stacked against obese people, scientists believe. Researchers wanted to understand why the body weight of people living in similar environments can vary significantly, and why some people seem to easily maintain a healthy body size while others struggle.
The team from Cambridge University showed in their paper published in the journal PLOS Genetics that while environmental factors such as eating low-calorie foods and a sedentary lifestyle contribute to obesity, thinness is as inherited as serious obesity, and both have a number of loci (the location of a genetic marker) in common.
Existing studies on families and twins have consistently shown that between 40 to 70 percent of variations in body weight are inherited, the authors wrote.
They asked if the genes that influence the thinness were “reverse sides of the same ‘coin’ ‘as those genes that influence obesity, or’ whether there are important genetic differences between them ‘.
To investigate this, the scientists compared the genetic data of 1,622 thin people (74 percent of whom saw thinness in the family), 1,985 severely obese people and another 10,433 individuals with a normal weight to act as the control.
Not only did the researchers discover genetic variants that are known to increase their risk of developing obesity, they found new genetic regions that are related to being slim or overweight. The team then calculated the genetic risk score of a person for obesity based on these variants.
Dr. Inês Barroso of the Wellcome Sanger Institute, who co-authored the study, explained: “As expected, we discovered that obese people had a higher genetic risk score than people with normal weight, which contributes to their risk of overweight there are dice loaded. ”
Co-author Professor Sadaf Farooqi of the Wellcome-MRC Institute of Metabolic Science, at the University of Cambridge, U.K., argued that the research dampened the idea that thin people are “morally superior, as some suggest.”
She said the research was the first to show that healthy thin people generally have this physique because “they have a lower burden of genes that increase a person’s chances of being overweight”.
Understanding how our genes affect our body size could pave the way for drug treatments, the authors wrote.
“If we can find the genes that prevent them from gaining weight, we might be able to focus those genes on new weight loss strategies and help people who do not have this benefit,” Farooqi said.
Tim Spector, professor of genetic epidemiology at King’s College London, UK, who was not involved in the study, commented: “This study shows what we have known in the last 15 years of twin studies, namely that genetics is important in your tendency to thinly or obese.
“In general, thin people are more likely to have multiple thin relatives and obese obese.” The genes found in this study add to the list found in larger studies and are useful for understanding mechanisms. but do not help in the individual prediction of obesity. “
He explained that about a third of people in most countries are slim, regardless of being exposed to unhealthy food. “Some of this is due to genes, but other factors such as individual differences in lifestyle or gut microbes are also likely to be responsible,” Spector said.
Waljit Dhillo, professor of endocrinology and metabolism, Imperial College London, who was not involved in the study, said it was well done with good controls. “It further emphasizes the importance that a person’s genetics makes an important contribution to the question of whether someone develops obesity or not,” Dhillo said.