Should You Eat Like Your Grandmother? The Science of Ancestral Diets

We live in an age of unprecedented nutritional choice. Supermarkets offer foods from every corner of the globe, diet trends arrive and disappear with the seasons, and the advice on what constitutes a “healthy” plate changes almost as often as the weather. Yet many of my clients find themselves returning to a surprisingly simple question: what did my grandmother eat — and could that be the answer?

It turns out, this is not a nostalgic indulgence. It is a question with serious scientific weight.

Your Genes Remember What Your Grandmother Ate

Modern genetics has revealed something remarkable: the foods your ancestors ate over thousands of years did not merely nourish them — they shaped your DNA. Groundbreaking research shows that the dietary shifts made after the Neolithic agricultural revolution, over 8,000 years ago, left lasting marks on our genomes. These genetic changes were not merely about survival; they were about thriving on the foods that were locally available, season after season, generation after generation.

The result is that our nutritional needs differ from person to person — not just because of our individual biology, but because of the unique genetic legacy inherited from our ancestors. And crucially, that legacy varies enormously depending on where in the world your family comes from.

I am of North Indian heritage, and as I will explore below, the traditional foods of that region — dahl, roti, ghee, homemade yoghurt, rice, and a rich array of spices — are not simply cultural comfort. They may represent thousands of years of accumulated biological wisdom encoded in the very fabric of my cells. I also notice I feel better when I eat these foods.

Three Powerful Examples of Gene-Diet Co-evolution

1. Starch and the Amylase Gene (AMY1)

One of the most elegant demonstrations of dietary adaptation concerns a gene called AMY1, which codes for salivary amylase — the enzyme in your saliva that begins the digestion of starch the moment food enters your mouth.

Humans have a remarkable and unique ability to carry multiple copies of this gene, and research has confirmed that populations whose ancestors ate high-starch diets — agricultural peoples who relied on grains, legumes, and root vegetables — tend to carry significantly more copies of AMY1 than populations from hunter-gatherer or pastoral traditions. More copies means more amylase, which means faster and more efficient starch digestion.

For someone of North Indian ancestry, whose forebears have been eating wheat, rice, and lentils for millennia, this matters. Your body may be better equipped to extract energy from these ancestral staples than from the low-carbohydrate, high-fat diets currently fashionable in the West — diets that evolved from entirely different ancestral contexts.

2. Dairy and Lactase Persistence (LCT)

You have probably heard of lactose intolerance — the inability to digest the sugar in milk beyond childhood. What is less well known is that the ability to digest dairy into adulthood (lactase persistence) is actually a genetic mutation that spread selectively through populations with long histories of cattle domestication and dairy consumption.

Populations across Northern Europe, parts of Africa, and the Middle East, where dairy farming has ancient roots, show high rates of lactase persistence. Parts of North India, with a similarly deep tradition of cattle culture, also carry elevated rates of this adaptation. This is why ghee, yohurt (dahi), lassi, and buttermilk have featured so centrally in traditional Indian diets for thousands of years — for many people of this heritage, these are genuinely well-tolerated, nourishing foods. For someone from a heritage with no dairy tradition, the same foods may cause genuine digestive difficulty.

3. Fatty Acids and the FADS Genes — A Revelation for Plant-Based Eaters

Perhaps the most fascinating example for those of South Asian ancestry concerns the FADS1 and FADS2 genes, which govern our ability to convert plant-based short-chain omega-3 and omega-6 fats into the long-chain forms — including DHA and EPA — that the brain, heart, and immune system depend upon.

Most of these long-chain fatty acids are found abundantly in oily fish. But populations whose ancestral diets contained little or no fish — including many communities across the Indian subcontinent with long vegetarian traditions — appear to have developed a specific genetic variant that upregulates FADS2 activity, making them more efficient at synthesising these essential fats from plant sources such as flaxseed, walnuts, and leafy greens.

In plain terms: if your ancestors were vegetarian for thousands of years, your body may be genuinely better adapted to a plant-forward diet than someone from a coastal fishing culture. This is not merely cultural preference. It is written into your biochemistry.

The Gut Microbiome: Your Inner Ancestral Ecosystem

Beyond your genome, there is another layer of ancestral adaptation that science is only beginning to fully appreciate: your gut microbiome. The trillions of bacteria, fungi, and other microorganisms that inhabit your digestive tract are not random lodgers. They are a co-evolved ecosystem shaped — over your lifetime, and across generations — by the foods your family has historically eaten.

Research into the Indian gut microbiome has found it to be distinctly different from Western microbiome profiles, characterised by microbial communities particularly adept at fermenting plant fibres, legumes, and complex carbohydrates. Experts in this field argue that dietary guidance for gut health in people of Indian heritage should be built around Indian staples — lentils, millets, vegetables, spices, ghee, and fermented foods — rather than simply transplanting Western nutritional frameworks.

The traditional Indian thali is, in this light, a masterpiece of intuitive nutritional design. It naturally combines:

Grains (roti, rice, millets) providing complex carbohydrates and B vitamins
Dahl and legumes supplying plant protein, prebiotic fibre, and iron
Vegetables contributing phytonutrients, antioxidants, and additional fibre
Fermented foods (curd, buttermilk, fermented batters) seeding the gut with beneficial bacteria
Ghee providing fat-soluble vitamins and supporting the absorption of fat-soluble phytonutrients
Spices delivering powerful anti-inflammatory bioactive compounds

This combination slows digestion, stabilises blood sugar, feeds beneficial gut bacteria, and delivers a broad spectrum of nutrients in a single meal. It is not coincidence. It is the accumulated nutritional intelligence of generations.

The spices deserve particular mention. Turmeric, cumin, coriander, black pepper, cinnamon, cardamom, and fenugreek — all staples of North Indian cooking — have been extensively studied for their polyphenols and bioactive compounds, which actively nourish beneficial gut bacteria and modulate inflammation. The traditional Indian kitchen was, quite literally, a pharmacy.

The Mismatch Problem: When Ancient Genes Meet Modern Food

Understanding ancestral adaptation helps explain something that many of my clients feel but struggle to articulate: a sense that modern food, however convenient, does not quite agree with them the way their grandmother’s cooking did.

The science gives this feeling a name: evolutionary dietary mismatch. The hypothesis, supported by a growing body of research, is that abandoning the evolutionary dietary environment contributes to chronic disease in modern humans. Ultra-processed foods are a very recent development — barely a blink in evolutionary time — yet they have become the primary food source for much of the population.

Our genes were shaped over thousands of years by whole foods: grains, legumes, vegetables, fermented foods, herbs, and spices. When we replace these with foods engineered in laboratories, stripped of fibre, loaded with refined sugars and industrial fats, and devoid of the phytonutrients our microbiome depends upon, we create a biological mismatch. Our ancient machinery is running on entirely the wrong fuel.

For people of South Asian heritage in particular, the rapid transition toward Westernised diets carries specific risks. The fibre-adapted microbiome that co-evolved with an Indian diet over millennia can be significantly disrupted by sudden, extreme shifts toward high-fat, ultra-processed eating patterns.

So, Should You Eat Like Your Grandmother?

The honest answer is: not necessarily exactly like her — but far closer than most of us currently do.

Your grandmother’s diet was not perfect. It was shaped by the constraints of her time, her geography, her economics. But it shared something with the diets of every generation before her going back thousands of years: it was built from whole foods, culturally specific ingredients, traditional preparation methods, and seasonal rhythms. It was, in all likelihood, free of ultra-processed foods, industrially refined oils, and artificial additives.

The wisdom encoded in traditional diets is not romantic mythology. It is the result of thousands of years of lived experimentation — of populations learning, slowly and iteratively, which foods helped them thrive in their particular environment. And increasingly, modern science is finding the molecular evidence that explains why.

What This Means in Practice

This is not a call to rigidly replicate a historical diet, nor to dismiss the nutritional value of foods from other traditions. Rather, it is an invitation to use your ancestral food heritage as a nutritional anchor — a foundation of foods to which your genes and microbiome are likely well-adapted — and to layer any modern nutritional refinements on top of that foundation, rather than discarding it entirely.

For those of North Indian heritage, this might look like:

Making dal, khichdi, and whole grain rotis the foundation of meals rather than occasional treats
Restoring fermented foods — yogurt, lassi, homemade pickles — as daily staples rather than curiosities
Embracing ghee as a quality fat rather than fearing it as a saturated fat cliché
Cooking with the full range of traditional spices, not merely for flavour but for their profound anti-inflammatory and microbiome-supporting properties
Choosing millets alongside or instead of refined wheat — as your ancestors did, and as modern research increasingly validates
Being cautious about dramatically low-carbohydrate diets if your ancestry is agricultural; your amylase genetics may mean you genuinely thrive on well-chosen complex carbohydrates

For those from other ancestral backgrounds — Scandinavian, West African, East Asian, Mediterranean, Indigenous — the principle is the same: look to your own food heritage with new eyes. The answer to what your body is best designed to eat may have been sitting on your grandmother’s table all along. What foods did your grandparents and great-grandparents eat?

A Note on Individual Variation

It is important to acknowledge that genetic adaptation operates at a population level. Not every person of a given heritage will carry identical variants, and our individual expression of these genes is influenced by epigenetics, the microbiome we have cultivated over our lifetime, and our personal health history. If you are curious about your own nutrigenomics — including FADS gene variants, amylase copy number, or lactase persistence status — these can increasingly be assessed through specialist testing, and I am happy to discuss this with you as part of a personalised nutrition consultation.

What the science consistently shows, however, is that the further we drift from our ancestral dietary roots — and toward the homogenised, ultra-processed global food supply — the greater the biological mismatch. Your grandmother’s kitchen was, in all probability, wiser than any diet trend you will encounter this year.

If you would like to explore how your personal ancestry, nutrigenomic testing and health history might inform a truly personalised approach to nutrition, please get in touch to book a consultation.

References available on request. Key research includes: Frontiers in Nutrition (2025) — Precision nutrition across climates: genomic adaptations in South Asian and Arctic populations; Perry et al. — AMY1 copy number variation and starch digestion; Kothapalli et al. (2016) — FADS2 variant selection in South Asian populations; Shondelmyer et al., Yale Journal of Biology and Medicine (2018) — Ancient Thali Diet: Gut Microbiota, Immunity and Health; Genome Biology (2024) — Recurrent evolution at the amylase locus.

This blog is for educational purposes and does not constitute medical advice. Always consult a qualified healthcare professional before starting new supplements or treatments.

Helen James is a Registered Nutritional Therapist, Functional Health Practitioner, and NLP Coach, and the founder of Find Your Healthy Life Limited. Holding a Post-Graduate Diploma in Personalised Nutrition from Middlesex University and additional qualifications in functional medicine and eating disorders psychology. She specialises in helping midlife women overcome hormonal disruption, supporting energy levels, digestion and gut health, and metabolic changes through personalised, root-cause health strategies. Registered with BANT and listed on the CNHC register, Helen works with clients one-to-one and delivers corporate wellbeing workshops.

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