Obesity Genetics and Prevention: New Research on Genetic Predisposition

What the latest genetic studies reveal about obesity, and how Personalized Precision Nutrition can shape its prevention?

Is It All in Our Genes?

Nutrigenetics has now been applied in clinical practice for a decade, and misunderstandings, confusion, and misinformation about the genetic predisposition to obesity still reach the public all too often. How many times have you heard someone say, “It’s genetic, no matter how careful I am, I just can’t lose weight”?

Since 2015, I have seen in my clinical practice hundreds of people struggle with their weight for years, following diets that “work for everyone”, except for them. The answer, as science increasingly confirms, is often found in their DNA. But that doesn’t mean DNA has the final word on whether or not obesity develops.

Obesity is a disease. It is not a matter of willpower. It is a chronic, multifactorial condition, in which genetics determines both the degree of risk and each individual’s starting point. Truly understanding one’s genetic predisposition is the first step toward meaningful prevention.

Obesity Isn’t One Disease. It’s Several

One of the most significant recent studies, published in Nature Medicine by a research team from the Icahn School of Medicine at Mount Sinai and the University of Copenhagen, analyzed genetic data from more than 450,000 people. The findings identified hundreds of genetic variants linked to increased body fat that were not also linked to increased cardiometabolic risk.

In other words: some people are genetically predisposed to obesity yet, thanks to a specific genetic profile, remain relatively healthy. While others, at a similar weight, develop diabetes or cardiovascular disease far more easily. The researchers identified eight distinct genetic subtypes of obesity, each with its own risk profile, and these findings held even in children.

This genetic knowledge essentially confirms what we see in clinical practice and in the day-to-day reality of different individuals: people who may fall under the “obesity” category based on the outdated Body Mass Index (BMI), yet whose clinical picture is clearly different.

Does this mean these individuals shouldn’t work on improving their weight? Absolutely not.

It means that the priorities they set, and the intensity of the effort required, cannot be the same for everyone. They must be tailored-made and personalized. This is, essentially, the foundation of the personalized precision nutrition we practice at DNANUTRICOACH: we do not treat “obesity” as a single, uniform condition, but analyze each individual separately, according to their genetic background.

How “Heritable” Is Weight Gain, Really?

Research led by Tom Bond (Πανεπιστήμιο του Bristol), involving tens of thousands of Norwegian families, showed that genetics explains approximately 79% of the mother-child relationship in BMI and 94% of the father-child relationship, within the first eight years of life. These are particularly high heritability rates.

The researcher and his team, however, are clear on one point: obesity is determined by the interaction between genes and the environment. A child who grows up in a healthy environment can avoid excess weight, even if they inherited genes that increase the risk. This is precisely the point of prevention through genetic knowledge: it is not about fatalism but about information that enables timely, targeted intervention long before the problem appears.

The Modern Environment “Activates” Genetic Predisposition

“We ate that stuff growing up, and we were fine.”

This is a common line I hear, mainly from parents who find it difficult to acknowledge that their child is living with overweight or obesity. It’s also a phrase I often hear from people over 55: the belief that all this focus on healthy eating and obesity prevention is, to some extent, exaggerated, because “back then we ate whatever we wanted and didn’t have all these problems“. Research from University College London explains exactly why this comparison doesn’t hold up.

The researchers analyzed four British generations, born in 1946, 1958, 1970, and 2001, and found something particularly critical: the same genetic predisposition to high BMI now has a far stronger effect than it did decades ago. The genes themselves haven’t changed. What changed is the environment around them (the obesogenic environment), which activates them from an early age.

I’ll put it the way my professor, Jose Maria Ordovas, does: genetic predisposition is like the bullet inside a gun.

The gun is already loaded; we don’t choose that, we inherit it. But who pulls the trigger, and how often, is our own responsibility, and it depends almost entirely on the environment we expose our body to from an early age: what it eats, how much it moves, how and how much it sleeps. Fifty or sixty years ago, that “gun” was just as loaded in many people; it’s simply that the environment of the time (fewer processed foods, more physical activity) pulled the trigger far less often.

Is a Genetic Predisposition to Obesity a Life Sentence?

This finding reinforces a key message I want you to remember: genetic predisposition is not a “life sentence.”

It is a vulnerability factor, a sensitivity, a predisposition, one that sounds an alarm bell of risk. In an obesogenic environment, it expresses itself far more strongly. Knowing about this predisposition gives us the advantage of “disarming” the environment before it can “activate” those vulnerable genes.

Why Some People Respond Better to Weight-Loss Medication?

A recent study in the journal Nature, based on genomic analysis of nearly 28,000 people undergoing treatment with GLP-1 type anti-obesity medications (such as semaglutide), identified specific genetic variants in the target receptors (GLP1R, GIPR) that partly explain why some people lose weight dramatically on these medications while others see almost no effect, and why some experience more side effects while others experience very few.

As a health professional and as a researcher in the field of precision nutrition since 2006, I always feel it’s important to point out the difference between studies based on statistical models and those based on direct genetic analysis of each individual. This means we need to recognize, and take into account, which study findings depend heavily on the population studied and the methodology used, and which have actually been confirmed in intervention studies.

This kind of balanced, careful evaluation is essential for anyone tasked with explaining genetics and giving practical guidance for dietary change, and I consider it fundamental to my own clinical approach.

From Knowledge to Practice: Why Prevention Starts with Nutrigenetics?

I have been applying nutrigenetics in clinical practice since 2015, and if there is one conclusion I’ve drawn from that experience, it is this: knowing our genetic profile is not a luxury. It is an investment in longevity and wellbeing.

Someone who learns early about their genetic predisposition to obesity and specifically, the type of predisposition they have, can take targeted action long before complications and symptoms appear that would make treatment more difficult. This isn’t about fear; it’s about preventive action: knowing in advance which areas need priority and closer attention, and taking care of them accordingly.

A genetic test on its own changes nothing. What has real value is what happens when genetic information is translated into a practical, personalized plan, and that requires a partner walking alongside you, not just a prescription.

Unfortunately, I very often see people moving from one specialist to another, taking a pill, a supplement, or a generic diet, with no one looking at the full picture. At DNANUTRICOACH, my philosophy has always been, and will always be, different: a 360° monitoring.

That means:

• Analyzing your genetic profile alongside your medical history, lifestyle, and lab test results
• A personalized nutrition plan based on scientific evidence, not trends
• Ongoing monitoring and adjustment, not a one-time set of instructions
• A focus on long-term prevention and longevity, not just weight loss

Obesity cannot be explained by a single cause. It is born from the sum of many.

Genetics is not destiny; it is a compass. And understanding your own is the first step toward a healthier, longer life.

Book a 15-min call today. I can help you choose the best program for you.