Know your curve - why finding the best way to eat starts with understanding your body

We all need to eat. And we all know that the foods we choose have a big impact on our health.

It also seems like everyone has an opinion on the best way to do it: low-carb, low-calorie, low fat, keto, paleo, high fiber, vegan, mindful eating. In a world of fad diets and conflicting advice, how do you know what’s right for you?

Here at ZOE, we believe that we are all unique and there is no one size fits all answer. To eat in a way that suits your body best, you need to better understand how you work.‍

Up and down

Humans are complicated, and there are many things that influence our health. 

There are things that are fixed or change very slowly, like our age, genes, height, weight and any medical conditions we might have. Other things can be altered or adjusted on a daily basis, including our choice of when and what we eat and drink, the drugs we take, our activities and how much we sleep.

Then there are the trillions of bacteria in the gut - collectively known as the microbiome - which have a significant impact on digestion and health.

We’re bringing all of these components together in order to unravel the complex relationship between diet, metabolism and health.

One key component is our nutritional responses to foods. This is a measure of how fast and how far the levels of molecules like fat, sugar (specifically glucose) and insulin rise in the blood after eating or drinking and how quickly they fall back to normal.

Tracking these levels over time and plotting them on a graph gives us a nutritional response curve, which changes depending on the individual person, the food they’ve eaten, the time of day, how active they’ve been and even how much sleep they had the night before.

For example, some foods cause blood sugar levels to rise moderately then return swiftly back to normal - this is a healthy nutritional response. Other foods trigger an unhealthy response, causing a rapid, high blood sugar spike followed by a crash, or blood fat levels that stay high for many hours. 

We know that there is a close connection between nutritional responses, metabolism and health. Unhealthy blood sugar responses after eating have been linked to weight gain and conditions like diabetes, while persistent high levels of blood fat are linked to heart disease.‍

Drawing the curve‍

Traditionally, doctors measure blood fat (triglycerides) and sugar (glucose) after fasting so they aren’t affected by the food we eat. But the levels of these and other important molecules in the blood change throughout the day as we eat and drink.

For example, blood sugar and insulin rise and fall after every meal or snack containing fat and carbohydrates, while fat slowly accumulates in the bloodstream. In turn, this impacts on the levels of other metabolic molecules in the blood, as well as hunger, mood and energy.

In total, a typical person might spend more than 18 hours a day in what’s known as a ‘post-prandial’ state, where blood fat and sugar levels are higher than those measured in the fasting state. What this means is that measuring our fasting levels of blood fat and sugar misses a lot of information about how our metabolism is really working. 

It’s a little like deciding whether to buy a car in a parking lot, without actually taking it for a test drive. You can judge how it looks and kick the tires, but to really know how well it works you have to go for a ride.

Adding to this complexity, people very rarely eat meals that are solely made of carbohydrates, fat or proteins. Instead we eat real meals, full of different foods that are locked together in physical and biochemical ways to create what’s called a ‘food matrix’. There are complex interplays between the different ingredients in the meal – something that gets overlooked in studies that just focus on single blood molecules or nutrients.

So it’s vital to capture the full daily pattern of responses to mixed meals, together with information about the microbiome, if we’re to really understand what’s going on inside the body on an individual level.

Here’s where our research comes in.‍

Making PREDICTions‍

Our PREDICT 1 and 2 studies form part of the first and largest nutritional response research programme to have brought together all these elements. 

We’re working in collaboration with nutritional scientists at some of the world’s leading academic institutions including King’s College London, Massachusetts General Hospital and Stanford University to monitor blood fat, sugar and insulin levels throughout the day in response to a range of meals and nutrients in thousands of people. We also gather information about microbiome diversity and data on activity, sleep, hunger and mood.

It all adds up to millions of measurements - the richest, largest dataset of its kind that has ever been gathered. 

The results from our first study, PREDICT 1, have recently been published in leading medical journal Nature Medicine. We measured nutritional responses in more than a thousand participants, including hundreds of pairs of twins, and were surprised to discover that even identical twins - who share all their genes and most of their environment - have very different nutritional responses to the same foods.‍

This tells us that there’s much more to metabolism than genetics, and that there is no one right way to eat for everybody.‍

We’re using artificial intelligence to use this data to predict about how an individual will respond to any given meal. Right now, our predictions are a good match for what happens in real life, and they will only get better as our dataset grows. 

We've also launched a home-based test and app that allows anyone to understand how their unique biology works. Ready to discover the foods that work best for you?