If you have ever followed exactly the same diet as someone else — a friend, a colleague, a sibling — and had completely different results, you have already experienced nutrigenomics in practice.

One person loses weight easily on a low-carbohydrate approach. Another person follows the same protocol diligently and loses almost nothing. One person takes a standard B-complex and their energy transforms. Another takes the same supplement and feels worse. One person reduces saturated fat and their cholesterol drops dramatically. Another person makes the identical change and their numbers barely shift.

These are not mysteries. They are the predictable results of biochemical individuality — the fact that each of us carries a unique genetic blueprint that profoundly shapes how we process food, metabolize nutrients, regulate inflammation, manage blood sugar, and store fat. Nutrigenomics is the science of understanding that blueprint and using it to inform genuinely personalized nutrition.

I became obsessed with nutrigenomics because of the clarity it offered to my own life experiences. Despite years of being an endurance athlete and following clean nutrition, I continued to struggle with hormonal balance and metabolic resilience during certain periods of my life. Standard nutrition advice never worked for me. Understanding my own genetic terrain and nutrient deficiencies did. And it changed everything about how I work with my clients.

 

What Nutrigenomics Actually Is

Nutrigenomics examines the interaction between your genetic variants — known as single nucleotide polymorphisms, or SNPs — and the nutrients, foods, and dietary patterns you are exposed to. It works in two directions simultaneously.

Nutrigenetics examines how your genes affect your response to nutrition: which nutrients you need more of, which you process poorly, which dietary approaches are likely to be beneficial or counterproductive for your specific physiology. Nutrigenomics also examines how what you eat affects the expression of your genes — because our genetic code is not fixed destiny. Nutrients act directly on gene expression, switching pathways on and off, regulating enzyme production, and influencing which genetic risks materialize and which do not.

The practical application of this is what I do in my practice. I process raw genetic data files from my clients and generate detailed reports that reveal which variants are present, what they mean biochemically, and how nutrition, targeted supplementation, and lifestyle modifications can address the specific pathways those variants affect. I then walk each client through their results and build a protocol that is grounded in their actual genetic physiology — not a generic template.

 

The Key Genes in Metabolic Health and Weight

Several genetic variants have direct and well-studied implications for metabolic health, weight regulation, and the conditions my clients most commonly struggle with.

FTO — the fat mass and obesity gene. FTO variants are among the most widely studied in metabolic health research. Certain variants increase leptin levels while reducing HDL cholesterol, creating an environment of persistent hunger and metabolic disadvantage. Individuals with the higher-risk FTO genotype respond particularly well to personalized dietary interventions and benefit substantially from understanding and working with their specific metabolic predispositions rather than applying generic weight loss approaches.

PPARG — the adipogenesis and insulin sensitivity gene. PPARG regulates how fat cells are formed and how sensitive tissues are to insulin. Variants in this gene influence carbohydrate and fat metabolism and determine in part how a person responds to different dietary macronutrient ratios. Someone with particular PPARG variants may have a significantly different metabolic response to a high-fat diet than someone without them — information that makes generic dietary advice at best ineffective and at worst counterproductive.

FADS1 and FADS2 — the fatty acid desaturase genes. These genes encode the enzymes responsible for converting the shorter-chain omega-3 and omega-6 fatty acids from diet into the longer-chain forms — EPA, DHA, and arachidonic acid — that the body actually uses. Variants in FADS1 and FADS2 significantly affect this conversion efficiency, meaning that some people cannot effectively produce anti-inflammatory DHA and EPA from plant-based omega-3 sources and require preformed EPA and DHA directly. This is one of the reasons I recommend fatty acid testing — because understanding both the genetic conversion capacity and the actual membrane fatty acid ratio gives a complete picture of an individual’s omega-3 status and what is needed to correct it.

MTHFR — the methylation gene. I have dedicated an entire blog to MTHFR, but in the context of metabolic health, its implications deserve mention here. Methylation — the biochemical cycle that MTHFR governs — is involved in insulin regulation, inflammation modulation, gene expression, and the production of the neurotransmitters that influence appetite, mood, and energy. Impaired methylation contributes to elevated homocysteine, which drives vascular inflammation, and to disrupted neurotransmitter balance, which affects the brain’s regulation of hunger and satiety. Addressing MTHFR is not peripheral to metabolic health — it is often central to it.

TNF and IL-6 — the inflammatory genes. Variants in genes encoding inflammatory cytokines like TNF-alpha and interleukin-6 determine in part how robustly the body mounts an inflammatory response and how quickly it resolves it. Those with higher-risk variants may experience more pronounced inflammatory responses to dietary fat, to gut dysbiosis, or to metabolic stress — driving the chronic low-grade inflammation that impairs insulin signaling, disrupts hormone balance, and makes weight loss physiologically difficult. Knowing these variants helps prioritize anti-inflammatory strategies and informs dietary fat choices in ways that generic guidelines cannot.

 

Why Generic Nutrition Advice Will Never Be Enough

Standard dietary guidelines are designed around population averages. They represent what tends to be beneficial for most people most of the time. But metabolic individuality is not marginal — it is the norm. The variation between individuals in how they respond to the same dietary inputs is not small. It is enormous. And for people struggling with weight, insulin resistance, hormonal imbalance, or chronic inflammation that does not respond to standard approaches, that variation is not an academic footnote. It is the reason they have not been getting better.

The conventional nutrition model asks: what should people eat? Nutrigenomics asks: what should this person eat, given their specific genetic, metabolic, and biochemical context? These are fundamentally different questions, and they produce fundamentally different answers.

A woman with FADS2 variants affecting her fatty acid conversion capacity needs more preformed EPA and DHA than someone without those variants — and she needs it in a tested, bioavailable form, not just a generic fish oil capsule. A man with PPARG variants affecting his insulin sensitivity may need a significantly different carbohydrate approach than his partner with a different genetic profile. Someone with compound MTHFR variants needs specific forms of B vitamins — standard forms will not work in their methylation cycle and may actively impair it.

This is not complexity for its own sake. It is precision — the difference between an intervention that works and one that doesn’t.

 

Genes Are Not Destiny

I want to be clear about something important. Understanding your genetic variants is not about receiving a fixed sentence. Genes are not destiny — they give us direction. What nutrigenomics reveals is not what will inevitably happen to you, but what is likely to happen if your nutrition and lifestyle are not calibrated to your specific biology.

The same FTO variant that predisposes someone to excess weight under a standard Western diet may have minimal metabolic consequences when that person understands their specific nutrient needs and eats accordingly. The MTHFR variant that has been driving elevated homocysteine for years can be managed effectively with the right forms of B vitamins. The FADS2 conversion deficit that has been leaving someone chronically omega-3 deficient despite years of fish oil supplementation can be corrected when the actual membrane ratio is tested and the right form and dose of supplementation is applied.

Nutrigenomics does not offer a cure. It offers clarity — a clear, personalized picture of the biological terrain that has been shaping your health, and a roadmap for working with that terrain rather than against it. For people who have spent years doing everything right and still not getting the results they expect, that clarity is not just useful. It is often transformative.

 

What This Looks Like in Practice

In my nutrigenomics consultations, I process raw genetic data and generate a detailed report covering the variants most relevant to my client’s health goals and symptoms. I then conduct a thorough consultation in which I walk them through what their results mean in plain language — what each variant affects, what it means for their specific situation, and what changes to nutrition, supplementation, and lifestyle are indicated.

The report and consultation give clients something most people have never had: a genuine baseline — a biochemically grounded understanding of their individual physiology that they can carry forward for life. Rather than chasing the next diet trend or supplement recommendation, they understand what their body actually needs. Interventions stop being trial and error. They become targeted and evidence based.

This is the future of personalized nutrition. And for many of my clients, it is the first time in years — sometimes decades — that they have finally understood why what they were doing wasn’t working, and what will.

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Brigitte Spurgeon is a Board-Certified Functional Genomics Practitioner and Doctor of Orthomolecular Nutrigenomics. She works remotely with clients across the US, Canada, Europe, Asia, Africa, and Australia, offering personalized nutrigenomics consultations, the Metabolic Pathway Strategy, and the Holistic Healing Strategy. To learn more or inquire about working together, visit www.brigittespurgeon.com

This article is for educational purposes and does not constitute medical advice.