We have spent decades blaming a lack of willpower for obesity. Genetics Just Proved Us Wrong

For decades we have heard about overweight and obesity that it is a problem of lack of willpower, of eating too much or moving too little. However, science has been trying to find more causes for years that we do not see with the naked eye about obesity to treat it as a complex, chronic disease with many different factors.

Two great studies recently published studies have provided very important evidence that suggests that the way we relate to food and the size of our body in childhood are not always ‘choice’, but are, to a surprising extent, an inheritance dictated by our DNA and amplified by the environment.

The weight of inheritance. The first of these studies published in PLOS Medicine analyzed to 86,000 children belonging to the Norwegian MoBa cohort. The goal here was to understand the extent to which parents’ BMI determines body size and the eating behaviors of their children at eight years of age.

The results have exceeded what many geneticists expected, since, using structural equation modeling, researchers discovered that genetics explains about 79% of the association between the mother’s BMI and that of the child. When we look at the father, the figure is even more compelling, since DNA explains approximately 94% of the association between the paternal BMI and that of the child.

Its importance. This means that when we see patterns of obesity that are repeated from parents to children and the determining factor is not mainly that “that house eats badly”, but that genetic variants are being transmitted that regulate key physiological aspects, from basal metabolism to the brain architecture that dictates the mechanisms of satiety and reward when eating.

The environment. At this point, it is inevitable to ask a reasonable question: if genetics is so determining, why have obesity rates skyrocketed in recent decades if our human genome has barely changed?

The answer the second study gives itpublished almost in parallel in PLOS Genetics where British researchers analyzed four large birth cohorts in the United Kingdom, namely people born in 1946, 1958, 1970 and 2001. The goal here was to measure how genetic risk interacts with the passage of time and changes in society.

Its result. What they saw was precisely that the genetic variants associated with obesity have become much more predictive of BMI in more recent cohorts. That is to say, having a genetic predisposition to gain weight in the forties did not necessarily ‘condemn’ obesity, because the environment did not support it. However, being born with that same predisposition in 2001 exposes you to a much greater risk.

Our genes interact with what epidemiologists call the obesogenic environment, which are sedentary urban environments, chronic stress, sleep disturbances and, above all, a constant, cheap and ubiquitous availability of ultra-processed, high-calorie-density foods. The modern environment acts as the trigger of a weapon that genetics had already loaded.

Much further. This avalanche of empirical data collides head-on with social stigma. As organizations such as the Spanish Society for the Study of Obesity have been warning for some time, it is urgent banish “Eat less and move more” is the only recommendation given in medical consultations.

It is for all this that understanding that obesity is a condition with a very deep genetic root, strongly conditioned by the environment, completely changes the rules of the game.

Images | i yunmai

In Xataka | We thought that quenching hunger with Ozempic was the definitive remedy against obesity. Until we look at the muscle