The twins who reveal why some people are more likely to gain weight

Obesity affects more than half of adults and a third of minors in Spain, according to research by the Carlos III Health Institute and the Spanish Food Safety Agency.

Weight gain worries many people, while many others do not gain weight even with a sedentary life without taking care of the calories they consume.

These differences have previously been attributed to genetics, but a group of researchers from Finland have found a new approach to discover why some people are more susceptible to weight gain than others.

The research, published in the journal

, is the first of its kind to decipher in a pair of twins with large differences in weight between each other, which of the two had acquired a body mass index (BMI) unequal to that genetically intended.

The study, carried out by the University of Helsinki, has investigated for 36 years the trajectory of the body mass index in twins who presented levels lower or higher than expected according to their genetics, with special emphasis on those who showed a great disparity between themselves.

The author of the study, Bram J. Berntzen, from the Institute of Molecular Medicine of Finland, assures that this “novel approach” opens doors to discover the factors that protect or predispose people to weight gain.

Additionally, he assures

that this methodology can offer valuable information on how to maintain a healthy weight.

More information

Childhood obesity in Europe and Spain: a complex and urgent challenge

Jaakko Kaprio, a geneticist in Genetic Epidemiology at the University of Helsinki and co-author of the study, explains that “a key finding” was that the predicted weight based on genetics was sometimes closer to the weight of the thinner twin, so it can be consider that the heavier twin deviates more from his biological disposition.

“This suggests that there are environmental reasons for gaining weight that have affected the heavier twin, and these can be studied more closely,” adds the researcher.

The main contribution of their work, the authors explain, is that in previous studies applied to twins with large weight differences, they had not established whether the twin with a higher or lower BMI is the one that deviates more from the genetic predisposition.

For this research, more than 3,000 Finnish twins of the same sex were examined.

The study began in 1975 and were followed in 1981, 1990 and 2011, providing a unique perspective on how weight patterns evolve over time.

The researchers found that the twin with a higher BMI in 1975 was more likely to deviate above the predicted BMI, compared to the twin with a lower BMI, who was more likely to deviate below the prediction.

This points to a genetic relationship between baseline BMI and weight trends over decades.

Individuals classified within or above prediction in 1975 showed consistent patterns, respectively achieving overweight and obesity by 2011.

According to this, they discovered that some people already had a genetic predisposition in their childhood to gain weight faster, while their twins did not.

Once in adulthood, they would gain weight in the same way.

Thus, they highlight the importance of studying the reasons why a child can gain much more weight than others.

This being the case, the

of eating everything someone wants without gaining weight disappears when the individual becomes an adult.

Jennifer Lovejoy, a translational researcher at Duke University in North Carolina, United States, who has not participated in the study, considers it valuable not only to focus the research on overweight twins and asks: “What protects some people from that we see twins who are thinner?

It is not entirely true that it is genetically determined.”

A pair of twins who participated in the Stanford and Netflix experiment.Netflix

In recent weeks, a

Netflix

) has put into the global conversation the possibility of using twins to study the effects of a disparate diet: omnivorous or vegan.

In the program, in just eight weeks, improvements in cardiovascular health were seen in those who followed the vegan diet.

However, the television program has some scientific weaknesses pointed out by specialists, and even divergences with the results published by Stanford University researchers in a scientific journal.

Therefore, the greatest achievement of the study published in

is not its present conclusions, but the window of opportunities it opens for future research.

By following this methodology, scientists explain that in the future it will be possible to study children from birth until they reach adulthood, with the aim of better understanding the factors that cause obesity and thus, finding formulas to combat it.

In the words of Kaprio, thanks to this discovery it is now possible to study two different groups: those who gain weight and those who lose weight separately: “This can help researchers understand how people maintain a normal weight and how they sometimes do not.” They are successful.”

And this, in turn, could have important implications for public health strategies and personalized treatments.

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