Most of us have this one friend who inexplicably manages to stay thin and trim no matter what they eat, but eventually scientists have discovered one of their secrets.
It's not just how active they are or their gut bacteria. Some people actually have a different genetic code that helps them keep the same weight for life.
The rest of us may need a little extra help.
Numerous previous research has linked genetic variations to obesity, but this study is one of the first to address genes associated with thinness.
The results suggest that there is indeed a "thin" mix of genes that can be inherited, or more specifically, the absence of obesity-associated genes.
"This study shows for the first time that healthy thin people are usually thin because they are thin. They have less exposure to genes that increase a person's chances of survival, and not because they are morally superior to some people like to claim, "says one of the two, Sadaf Farooqi from the University of Cambridge in the United Kingdom.
"It's easy to judge and criticize people for their weight, but science shows that things are much more complex, we have far less control over our weight than we might want to think."
By comparing the DNA of 1
They examined lifestyle questionnaires to exclude other lifestyle factors that could make a significant contribution, such as eating disorders.
The researchers found that the so-called genetic risk score for obese people is much higher than it is for thin people.
In other words, thin people tend to have fewer genetic variants that increase the likelihood of developing obesity.
In addition to the known genetic variants already associated with obesity, the team found new variants that relate to obesity as well as to healthy thinness.
Among the naturally thin people in the study, the researchers also found that 74 percent, or nearly three quarters, of them had a family history in which they stayed thin and healthy. 19659002] In the process, scientists want to identify more genes and biological mechanisms that help people maintain the right weight.
Of course, genes are not everything.
As in Previous Research How to show how thin or fat someone is can be due to a whole range of factors – from the rate of metabolism and exercise to the temptation to find fatty foods – but these New study shows that genetic factors play a big role. 
The study does not say that thinness and obesity are anything to do with genetics, but it suggests that the daily mockery of burgers and chips will lead to different weight gains for different people – and people on the obese The end of the scale, which are most likely able to hold genetic variants responsible.
"The genetic cubes are being charged against them," says one of the researchers, Inês Barroso of the Wellcome Sanger Institute in the UK.
Ultimately If we want to handle our weight, we will not all start with a level playing field, but our actions make a difference – what you should consider the next time you consider traveling to local fast food chain. Diet and exercise are still of great importance to our health.
"We already know that people can be thin for a variety of reasons," says Farooqi. "Some people just do not care about food, while others can eat whatever they want, but never increase."
"If we find the genes that prevent them from gaining weight, we can target these genes to find new weight loss strategies and help people who do not have this benefit."
The research was published in PLOS Genetics .