Obesity is a much more complex issue than a single gene

The obesity has been a growing issue worldwide. With each passing day, people eat more and exercise less. Furthermore, with the proliferation of the famous fast-foods, industrialized food and other types of nonsense are increasingly entering the diet of the average population. Consequently, obesity is becoming one of the most serious and serious problems in the entire world.

Obesity is cited by doctors as a plague of the 21st century. If it is seen with such urgency by specialists, it is because it is one of the things that most lead to death nowadays. In short, the number of people with obesity tripled between 1975 and 2016.

As if that wasn’t worrying enough, children are getting more and more obese. In the UK today, nearly a third of children are overweight or obese.


Obesity is related to several health problems. And more recently it has also been shown to increase the risk of serious illness after infection with COVID-19.

Of course, several factors can contribute to obesity . One of them being genetics. And five experts in genetics, nutrition, obesity and neuroscience were asked if there really is an obesity gene.

To analyze the genetics behind obesity, researchers analyzed the DNA of several people to see if they could identify certain genes or gene variations that correlated with obesity.

“Large-scale genome-wide association studies (GWAS) have identified multiple loci associated with body mass index and not just a single loci/gene. However, in rare cases, obesity is caused by a specific syndrome due to a mutation in a gene,” said Cornelie Nienaber-Rousseau, nutrition expert at North-West University in South Africa.


Those genes that correlate with body mass index or obesity vary quite widely in their function. University of Portsmouth neuroscience specialist Ivor Ebenezer explains that “these genes control hormones, neurotransmitters, neuromodulators and enzymes involved in regulating food intake and energy homeostasis.”

If looked at from an evolutionary perspective, it doesn’t make sense that genes that are passed on from generation to generation help people to have a dangerous condition such as obesity .

“If we look back in history to a time when our hunter-gatherer ancestors roamed the land, we find that primitive man lived primarily on plant roots, which are rich in carbohydrates, and animals hunted for protein and fat. There were periods of many days and sometimes weeks when they were hungry. Those who survived were able to store body fat in times of plenty to provide energy in times of difficulty. So most of us inherited genes from our ancestors that predispose us to accumulate body fat,” explained Ebenezer.

Such genes played an essential role in survival when food was scarce. However, they are currently harmful to people. Since we have easy access to food and we don’t have to physically struggle to get it.


As much as genetics is a factor influencing obesity, it is not the only one. “Obesity is an extremely complex trait controlled by interactions between many genetic and environmental factors. Just look at the changes in obesity levels that we see in modern populations versus our recent ancestors. Our genes have not changed remarkably during this period,” explained Richard Edwards, an expert in bioinformatics and genetics at UNSW Sydney, Australia.

A factor that strongly influences is the environment in which the person lives. “Obesity is due to an excess of energy intake, that is, food, together with a decrease in energy expenditure”, pointed out Ebenezer.

In addition, Ebenezer also explains that “environmental factors, such as maternal hunger or consumption of foods high in sugar, can produce epigenetic changes in the fetus that can result in obesity in the offspring.”

In conclusion, we see that, as much as genetics contribute to obesity, it is not the only factor that is involved. And there is not just one “obesity gene”.