What is the Zoe test and how does it check our health? We try it out
Without quantifiable data about your body and the way it metabolises certain foods, making changes to your lifestyle to counteract ageing – or so-called “biohacking” – may be a shot in the dark.
This was partly my reason for doing the Zoe test. I kept seeing people with yellow stickers on the backs of their arms, learned about Zoe, and wanted to gain insight into how my body really responds to foods.
Tim Spector, a British medical doctor and professor of genetic epidemiology at King’s College London, launched Zoe in 2018. It is a personalised nutrition testing kit with tools for assessing microbiome health, which includes a continuous glucose monitor (CGM) – held in place by a yellow sticker.
You wear it for two weeks to obtain a cross-section of results, which the Zoe app uses to recommend certain foods to eat that give you fewer blood-sugar spikes.
The aim is to gain insights that allow you to stabilise your blood sugar and fat levels and boost your gut bacteria, which Zoe says is the key to achieving a healthy weight and improving long-term health.
A big spike in glucose in the blood causes a big spike in the body’s production of insulin, which blocks fat burning and stimulates fat storage, according to Zoe.
Reducing the glucose spikes also helps reduce inflammation, sustain energy and control hunger. This reduces the risk of having diabetes and heart disease.
Zoe tests the bacterial make-up of your gut through a stool sample, and your metabolic rate by having you eat a blue-dyed cookie and logging how long it takes to pass through your intestines.
Zoe is an investment: it costs £270 (HK2,670) upfront, which includes the gut microbiome test, the blood sugar and blood fat tests, cookies and a blood sugar monitor.
Along with the test kit, you must also buy a subscription to the Zoe app, which costs £45 a month. Its contents come in individual, clearly labelled yellow boxes. You first download the app, which is straightforward and gives clear advice about attaching the CGM to your arm.
I pushed the CGM onto my arm; the needle went in and did not hurt at all. Immediately, I started tracking my blood sugar level and could see when mine was in range, peaking or dropping. Checking your blood sugar does become bizarrely addictive, and I found myself checking mine throughout the day to see how I responded to different food combinations.
I was surprised at the ways my blood glucose levels could be sent high, such as by eating a baked sweet potato with butter and olive oil, or a green apple.
I also got a spike running on an empty stomach – intensive exercise raises glucose levels because our cortisol triggers the liver to release stored glycogen – although that sort of spike is not considered a harmful one.
Why should we care about what our blood sugar is doing? There is evidence to suggest that extreme glucose spikes, over time, can cause inflammation and increase our risk of heart disease and type 2 diabetes.
On the first day of Zoe testing you eat two cookies for breakfast and two more for lunch. The breakfast cookies are thick and rusk-like, with white chocolate chips – and contain over 600 calories.
My blood sugar spikes, although not out of the guide range.
The lunch cookies are coloured bright, royal blue, to enable you to understand your gut transit time.
Zoe’s research shows that gut transit time is a key indicator of gut health, with shorter times generally associated with better health.
I kept waiting for my blue poop, but I never saw it. Zoe says many users never see a blue poo; sometimes the gut breaks down the dye.
After eating the cookies you do a blood test, which requires a small, self-administered nick on a finger to get a drop of blood.
Then comes the poop sample, which you send off in a preaddressed envelope with the blood sample.
It takes six weeks to receive your results.
Mine presented no groundbreaking or life-changing information.
My blood sugar control scores 91, “excellent”, while my blood fat levels are “good” and my gut biodiversity is “excellent”.
The foods I was recommended to eat more and less of were predictable – more of those containing lean proteins and healthy fats, grains and leafy vegetables, and less of those containing refined carbs, and processed food.
The microbiome analysis aims to show you how diversely populated by good or bad bacteria your gut is, given that this plays an important role in maintaining a strong immune system.
I was in the upper 25 per cent of scores, with 121 species of microbes in my gut: my score was 83 – “excellent”.
“Generally speaking, higher diversity is better because you are more likely to have some beneficial microbes in there,” Zoe says.
After getting the results, you enter the final stage, which is maintaining better food choices – the app says it can predict blood sugar responses to foods and suggest ones which will keep you more level.
I did not feel I was receiving much helpful insight, although one habit I have maintained since trying Zoe is to mix my carbs with fats when having a snack – for example, having Greek yogurt with blueberries and banana, or eating an apple with peanut butter.
Is it worth the money? I would say that most of us already know what we need to do to be healthier.
A blood monitor and app is not going to take those steps for you.
I cancelled my app subscription.