Genetics allows you to very accurately predict how fat a person will be
People with obesity in a modern society infected with leanness are stigmatized: most are convinced that their thickness is caused by gluttony or the wrong foods, that is, a weakness in character. In reality, as a rule, obesity is a consequence of genetic disorders.
Extremely obese, or morbid obesity, affects already 8% of Americans, and this is one of the most acute medical problems of mankind. Morbid is called obesity if the body mass index (weight in kilograms divided by the square of height in meters) in a person is 40 or more. In poor countries – such as India or China – the situation is not so dramatic at first glance: less than 1% of the population suffers from morbid obesity, but, firstly, it’s tens of millions of people, and secondly, over the past thirty years, the proportion of the population with morbid obesity has grown in such countries more than a hundred times! And there are no signs of a slowdown in this process.
Of course, obesity is caused by an unhealthy lifestyle; it may be a consequence of the poor state of the environment, but to a greater extent this is a manifestation of heredity. Scientists from the Massachusetts Institute of Technology and Harvard, as well as their British counterparts from Bristol, have proposed a system of genetic predictors that allow you to assess at a young age the chances of a person becoming fat or very fat. In rare cases, a hereditary predisposition to obesity can be explained by a single mutation that changes fat metabolism or leads to the deposition of large stores of fat. Such, for example, is the genetically determined inactivation of one of the melanocortin receptors – a similar disorder causes obesity in both humans and mice.
But most obese people become obese due to polygenetic disorders. A work is known in which the correlation was estimated between 2.1 million genetic variants known to science and 300 thousand people, more precisely, their body mass indices. None of the options gave a statistically significant phenotypic picture.
This makes it clear that a genetic predisposition to obesity is a cumulative effect of numerous changes, each of which makes a modest contribution to the overall picture. Researchers introduce a genome-wide indicator (GPS) for evaluation, which combines all common options into a single quantitative indicator of the hereditary cause of obesity. This indicator determines the subset of the adult population that is at significant risk of morbid obesity. At birth, the influence of this indicator is almost imperceptible, differences in the weight of infants are minimal, but it clearly predicts an increase in differences in weight in early childhood and a significant gap in the trajectory of weight gain in the next years of development – up to the diagnosis of morbid obesity.
Before you blame your genes, try to change your lifestyle
Although genes play an important role in obesity, laziness and bad habits contribute to this no less.
Many obesity victims explain their weight problems only by heredity, not trying to change their lifestyle.
Although genetic factors can be significant in gaining excess weight, they are not critical. And yet, most fat people could reduce their weight due to proper nutrition and physical activity, without attributing all their troubles to “their ancestors”.