We’ve all heard the phrase ‘you are what you eat’, but what if we’ve only heard half of the story?
According to Professor Vimal Karani, Professor of Nutrigenetics and Nutrigenomics at the University of Reading, what we eat interacts with our DNA and contributes to how our bodies function.
“Nutrients communicate with our genes,” he says. “They can influence everything from how we metabolise fat to how we age.”
Welcome to the world of nutrigenomics: a fast-evolving field where genetics meets nutrition. It’s a space that’s quietly transforming how we understand food, metabolism, and ageing.
The promise (and limits) of nutrigenomics
At its core, nutrigenomics explores how food interacts with the expression of our genes. This process is known as gene expression and is where DNA is converted into the proteins that make us who we are. But as Professor Karani points out, we’re still in the early stages.
“We have captured only around 8% of the genetic variations linked to obesity,” he explains. “Without understanding the remaining 92%, we cannot yet develop truly personalised DNA-based diets.”
In other words, we’re not quite at the point of scanning DNA and receiving a perfect menu plan. Still, the field has made promising advances.
Emerging research shows that our genes can subtly shape how our bodies respond to what we eat and drink. For example, some studies suggest that those carrying a particular variation in the FTO gene may be more likely to gain weight when following a higher-fat diet, while another gene, CYP1A2, affects how quickly we process caffeine. This may help to explain why some of us can enjoy an afternoon coffee with no trouble sleeping, while others find it leaves them wired late into the night.
“It’s early science,” says Vimal. “What we do know is that the interaction between food and genes is real and incredibly complex. Two women could eat the same meal and have completely different metabolic responses. Understanding that difference is the key to smarter nutrition.”
When one size doesn’t fit all
For many women, the lightbulb moment comes when they realise the problem isn’t about discipline, it’s their biology.
Take Sarah, 47, from Bath. After years of yo-yo dieting and sluggish energy, she took a basic nutrigenetic test (around £100 online) that suggested she had a variant linked to slower carbohydrate metabolism.
“It finally made sense,” she says. “Whenever I ate a big pasta dinner, I felt exhausted the next day. The test gave me permission to eat in a way that actually suited my body.”
She swapped refined carbs for lentils, quinoa and sourdough, and within a few weeks noticed clearer skin, fewer sugar crashes, and better sleep.
Then there’s Helen, 52, who’d been taking high doses of vitamin D without seeing any improvement in her blood levels. Her genetic results revealed a variant in the GC gene, affecting vitamin D transport. “My nutritionist adjusted my supplement type and dosage, and within three months my energy was up, my mood was lighter, and my winter blues had eased,” she says.
“It’s not that DNA is destiny,” says Vimal. “But that knowledge is power. If you understand your body’s tendencies, you can make more effective choices.”
The midlife advantage
For those of us in midlife, the benefits of eating for our genes go far beyond vanity. Hormonal fluctuations during perimenopause can alter how the body metabolises glucose, stores fat, and regulates mood. This is precisely where nutrigenomics could help.
“Midlife is a critical window,” says Vimal. “Oestrogen decline affects everything from inflammation to insulin sensitivity. Nutrigenomics helps us understand how dietary compounds (like omega-3 fats, polyphenols, or curcumin) can interact with the genes involved in those pathways.”
For instance, preclinical studies have shown that curcumin (found in turmeric) and ashwagandha may modulate genes linked to mood, anxiety, and immunity, offering a natural buffer during hormonal transition. Similarly, compounds in green tea, berries, and dark chocolate are thought to help support SIRT1, a longevity gene associated with improved mitochondrial function and reduced inflammation.
“Think of food as information,” Karani explains. “Every bite sends signals to your genes, telling them to repair, regenerate, or rest.”
Can we eat for our genes without a test?
While full DNA analysis can cost anywhere from £100 to £400, we don’t necessarily need a fancy kit to start eating for our genes. Here are some practical, evidence-backed ways to get started:
Embrace bio-individuality
No two metabolisms are identical. Keep a simple food and mood journal for two weeks. Note what you eat, when, and how you feel afterwards such as energy, mood, bloating, and sleep as patterns often reveal more than a test.
Prioritise diversity over restriction
Research from the American Gut Project – one of the world’s largest studies on the microbiome – found that people who eat more than 30 different plant foods a week tend to have a richer, more diverse gut microbiome. Greater diversity is linked with stronger immunity, steadier weight and even better mood balance. The secret? Aim for colour, texture and variety, not perfection.
Balance your macros for midlife metabolism
Protein becomes increasingly important in midlife to counteract muscle loss. Your intake will depend on your weight and activity level, but aiming for 20-30g per meal is a good rule of thumb. Combine with complex carbohydrates and healthy fats to stabilise blood sugar and reduce inflammation.
Eat with your ancestry in mind
Karani’s research suggests ethnic background still matters. “In Indonesia, we found that people consuming excessive protein had a higher genetic risk of obesity, but those following traditional dietary recommendations overcame it,” he explains.
Support your ‘longevity genes’
Add foods rich in polyphenols (blueberries, olive oil, dark chocolate), omega-3s (salmon, flaxseed), and spices like turmeric. These help activate genes that regulate inflammation and repair.
Rethink caffeine and alcohol
Variants in the CYP1A2 gene affect caffeine metabolism. Slow metabolisers may experience anxiety or disrupted sleep. Similarly, alcohol sensitivity genes can influence liver enzyme activity so if you’re jittery or sleepless after one coffee or glass of wine, your genes might be telling you something.
Consider testing… wisely
If you’re curious, choose a provider that uses reputable labs, offers transparent data policies, and ideally works alongside registered dietitians or doctors. Avoid companies making sweeping health claims or failing to disclose how your data is stored.
The verdict
While nutrigenomics isn’t a silver bullet, and is still in its infancy, it’s does offer a new language of self-understanding. Instead of calorie counting or chasing the latest trend, it reframes nutrition as a conversation between your plate and your DNA.
For Lisa, 49, from Liverpool, that shift was life-changing. “I stopped thinking of food as punishment and started thinking of it as information. When I eat to support my genes through plenty of plants, mindful portions, fewer ultra-processed foods, my body thanks me.”
And perhaps that’s the quiet magic of nutrigenomics. It’s not about predicting your future, it’s about participating in it. One forkful at a time.
