# Your Diet Talks to Your Genes — Season by Season **By Merve Tigli** · 2026-08-24 Two people can follow the same eating plan for a month and come back with very different blood results. It's tempting to blame willpower or bad luck, but a study published in _Nature Communications_ this August points to something more interesting: your genes respond to what you eat — and even to the time of year you eat it. Same diet, different results is not a myth; it's partly biology. This is one of the clearest looks yet at **gene–diet interaction** in real, healthy people. ### Proteogenomics, in One Line Proteogenomics simply means studying your genes and your proteins together — reading the DNA instructions _and_ checking how they actually show up as working molecules in your blood. Proteins are where genetics becomes daily life: they carry your cholesterol, run your immune responses and process the amino acids in your dinner. So if diet changes how genes are expressed as proteins, it changes something that genuinely matters for health. ### What the Researchers Actually Did A team led by researchers in Greece followed **200 healthy adults** who, for religious reasons, regularly alternate between an ordinary omnivorous diet and periods of avoiding animal products — a long-standing Orthodox fasting tradition that acts like a natural, repeating diet experiment. Alongside them, **211 people who ate omnivorously all year** served as a comparison group. By taking blood samples over time and pairing each person's genotype with measurements of their blood proteins, the team could ask a precise question: do the effects of specific genetic variants on protein levels change when the diet changes? ### Genes That Listened to the Menu They do — at least for some proteins. The study found **diet-responsive genetic effects** on proteins including: - **LBR**, a protein involved in **cholesterol metabolism**. Strikingly, one genetic variant near LBR only showed a shared signal with obesity during the periods of animal-product restriction — suggesting that a piece of genetic risk can be turned up or down by the diet you're on. - **MSRA**, linked to **methionine metabolism** — methionine being an amino acid that's especially abundant in meat, eggs and dairy, exactly the foods that cycled in and out of these diets. - **FGF21**, a metabolic regulator whose diet-dependent genetic signal overlapped with immune-cell and platelet traits — a hint that food, genes and **immune function** are in closer conversation than we usually assume. ### And Genes That Listened to the Calendar The comparison group revealed the second surprise. In people whose diet stayed the same all year, several genetic effects on proteins drifted with the **seasons** — notably proteins involved in immune-system pathways, such as MAVS and CASP3. In other words, a genetic variant's influence on your biology in January isn't necessarily its influence in July. Curiously, some of these seasonal patterns appeared to be masked in the fasting group, another sign that diet and season interact rather than acting alone. ### What This Does _Not_ Mean Here's the part I care about most as a dietitian: **none of this means you need an expensive DNA-diet test.** This is early, population-level science. It shows that context — what you eat, and when — changes how genetic effects play out. It does not show that testing your genes can tell you which diet to follow, and the commercial gene-based diet tests on the market today can't reliably translate findings like these into a meal plan. The evidence so far doesn't show gene-matched diets outperforming good, standard personalised advice. If anything, the study argues the opposite of the DNA-test sales pitch: your genetic "settings" aren't a fixed verdict to be decoded once, because they shift with your diet and the season. ### What You Can Take From It The practical message is gentler and, I think, more freeing: - **One diet for everyone was never realistic.** Your neighbour's results on a plan are evidence about your neighbour, not about you. - **Your own response is the best data you have.** Blood results, energy, digestion and appetite over weeks tell you more than any consumer gene report currently can. - **Seasonal shifts are normal biology, not failure.** If winter and summer feel metabolically different, that may be real — build flexibility into how you eat rather than judging yourself against one fixed template. - **Plant-forward periods are a legitimate lever.** The study's "natural experiment" was simply cycling animal products down and up — an everyday dietary pattern, not a lab concoction. I find this study genuinely hopeful. It says your biology is responsive — listening to your grocery list and the calendar alike — which means food remains one of the most powerful, adjustable tools you have. If you're curious about the wider field, I've looked before at [how nutrigenomics thinks about genes shaping your diet](https://www.nfitdiet.com/blogs/news/nutrigenomics-let-your-genes-shape-your-diet); this new research adds the missing piece — your diet talks back. ### Prefer to Watch? If you'd rather watch than read, I've covered this topic in a video on my YouTube channel. [Watch on YouTube](https://youtu.be/Bd9fqo7hQis) _This article is for general information and isn't a substitute for individualised advice from your own doctor or dietitian._ _Merve Tığlı, Dietitian_ _Sources: Simistiras A. et al. — [Diet-responsive proteogenomic effects following short-term restriction of animal products in humans](https://www.nature.com/articles/s41467-026-76379-6), Nature Communications (2026); Systematic discovery of gene–environment interactions underlying the human plasma proteome in UK Biobank, Nature Communications (2024)._ **Tags:** genetics, nutrition, personalised-nutrition, wellness --- > Source: [nFit Diet & Nutrition](https://shop.nfitdiet.com/blogs/news/your-diet-talks-to-your-genes-season-by-season)