Published 12th April 2022

Understanding the connection between diet and health

ZOE’s focus has always been on understanding and maximizing health for everyone, whether that’s through the ZOE COVID Study or our work on nutrition and the microbiome

We’re now broadening our focus through Wider Health Studies, using our unique data-driven approach to tackle some of the biggest health challenges we face today, including cancer, heart disease, and dementia. 

Together with our study contributors, we’ll be investigating how our lives shape our health, immunity and wellbeing, based around five interconnected strands of health:

  • Diet

  • Sleep

  • Physical activity

  • Brain health

  • Social and health habits

How does your diet affect your health?

Whatever else we do for our health, we all have to eat. And while the primary function of food is to provide the energy and molecular building blocks we need to keep our bodies alive and functioning, the deeper connection between diet and health has been recognized for centuries. 

Around 400 years B.C. the ancient Greek doctor Hippocrates was writing about how “good” and “bad” foods were connected with health and disease, although he never actually penned his most famous quote, “let food be thy medicine and medicine be thy food.”

Today, we know that diet has an important impact on many aspects of health, immunity, wellbeing, and our risk of many diseases. There’s also growing interest in the role our trillions of gut microbes (gut microbiome) play in everything from metabolism to mental health.

It’s also becoming clear that repeated unhealthy inflammation in response to certain foods (which we refer to as dietary inflammation) is the missing link between the foods that we eat and the risk of chronic conditions linked to diet and metabolism, such as diabetes and heart disease.

How can we study the connections between diet and health?

In the past, most studies of nutrition and health were limited to small-scale, highly controlled clinical trials, which were difficult and costly, or larger survey-based studies that couldn’t capture the detailed complexity of how people eat and live on a daily basis.

Advances in technology allow us to build a much more sophisticated picture of the complex connections between diet, health, and disease on a scale that was unimaginable just a few years ago. 

We now have devices to precisely measure the inputs and outputs of the body, including wearables like stick-on glucose monitors and wristwatch-style activity and sleep trackers, as well as fingerprick blood tests that provide a detailed analysis of metabolic health. 

Researchers are also able to use the latest DNA sequencing technologies (known as shotgun metagenomics) to identify the many thousands of different species of bacteria  living in our guts, which play a key role in health and immunity.

Our team here at ZOE, together with our research colleagues at King’s College London and other academic centers around the world, are bringing all of these advances together in PREDICT - the largest in-depth nutrition research program of its kind in the world, with thousands of participants in the U.K. and U.S. 

And we’ve now launched our Health Studies hub through the ZOE COVID Study app, working with our hundreds of thousands of regular Contributors to carry out large-scale research that will shed light on the most pressing health issues facing us today and reveal more about how our lives shape our health.

It all adds up to a huge amount of data, so we use tools such as machine learning (ML) and artificial intelligence (AI) to sift through it in search of patterns and insights to help us understand more about how what we eat affects our health, metabolism, immunity, and mental wellbeing.

What has ZOE discovered about diet and health?

Over the past few years, our research has revealed important insights into nutrition, the microbiome and health, which we’ve published in leading peer-reviewed scientific journals and presented at major international conferences.

One of our first big discoveries was that even genetically identical twins can have different metabolic responses after eating exactly the same foods, demonstrating that genetics plays a relatively small role in determining how our bodies respond to food. 

We’ve also discovered that the overall quality of your diet is linked to the balance of "good" and "bad" microbes in your gut and your metabolic health. And we showed that unhealthy blood sugar and fat responses after eating are associated with a rise in inflammation, which is linked to chronic health conditions such as diabetes and heart disease. 

What’s more, ‘big dippers’ - people who have big blood sugar dips several hours after eating - end up feeling hungrier and eating hundreds more calories during the day than ‘little dippers’ who have more controlled blood sugar responses.

Over the past two years we’ve been able to use the ZOE COVID Study app to find out how the pandemic disrupted people’s diet and lifestyle, and explore how what we eat influences our risk from COVID-19.

A huge number of app Contributors responded to our detailed diet and lifestyle questionnaires, making it the largest study of its kind anywhere in the world. The results showed that people who ate a high quality, plant-rich diet were less likely to catch COVID-19 or become seriously ill

We also saw a high degree of variability in the effects on diet and other health behaviors during the first year of the pandemic, reflecting the wide range of circumstances and impacts across society.

What’s the best diet for health?

There’s plenty of advice out there about the most healthy diet - from low calorie to low carb, paleo to vegan - and much of it is confusing and conflicting. So what’s the best diet to follow for your health?

Based on the latest research from ZOE and others, such as the U.S. DIETFITS study, it’s becoming clear that there is no single ‘best healthy diet’ that will work for everyone, and no specific ‘superfoods’ that are guaranteed to give you good health (which owe more to marketing than sound science).

Generally, the evidence suggests that habitually eating a high quality, diverse, plant-rich diet with more whole foods and fewer ultra-processed foods is the best approach for supporting your health and microbiome. But beyond that, the best kind of eating pattern for your health depends on your personal metabolism and microbes.

What do we still need to discover about diet and health?

Despite all the progress that has been made in recent years, there are still plenty of unanswered questions about the connections between our diet,gut microbiome, health, immunity, and wellbeing. 

For example:

  • How do specific foods affect different species of gut microbes?

  • Do alterations in the gut microbiome play a causal role in health and disease, or do they reflect what’s going on?

  • How does our diet, microbiome and hormonal changes work together during the menopause to affect health?

ZOE’s large-scale, data-driven approach offers a powerful way to find answers to these questions and more, not just for diet but across all five strands of health

Our Wider Health Studies aim to connect each of our personal health journeys to patterns in the wider population, revealing new insights into health and disease that could help us all lead healthier, happier lives. 

Together, we’re changing the future of health research. To get involved, simply download the ZOE app, fill in your health profile, and get in the habit of logging daily health reports. We’ll be adding new studies and research activities as we bring them online, so watch this space for updates.

Help science and keep logging.

Explore the ZOE Health Academy to learn more about the science of nutrition, healthy living, and immunity.