Frequently asked questions

You will need to have signed up to the ZOE Health Study as a ‘primary profile’ (so not reporting for anyone else) and be based in the UK. You will also have to opt in to be part of our Wider Health Studies and contribute your data to research beyond COVID-19.   

You can check your opt-in status by going to the menu bar in the app, in the top right corner of the homepage, and clicking on the ‘Wider Health Studies’ section. 

If you have questions about your participation and personal health risks, please contact your healthcare provider particularly if you have Type 1 diabetes, history of an eating disorder, or an uncontrolled medical condition. Please also consult your healthcare provider before starting this study if you are pregnant or breastfeeding.

We advise that you don’t join this Intermittent Fasting Study if you’re currently in the testing phase of the nutrition programme, or are going through the 12 week (3 month) programme. This is so that you can fully participate in the nutrition programme and complete all the stages.

If you’re more than 3 months into the nutrition programme or on the waitlist then you’re welcome to join the Study.  

Intermittent fasting is considered to be safe for the majority of people with adverse effects being uncommon. That said, we're all unique individuals and adverse effects may be possible for some. Please direct questions about your participation and personal health risks to your individual healthcare provider, in particular if you have Type 1 diabetes, history of an eating disorder, or an uncontrolled medical condition. Please also consult your healthcare provider before starting this study if you're pregnant or breastfeeding. We are unable to provide medical advice. Your participation is voluntary and you can withdraw from the study at any time.

Medications prescribed by your healthcare provider do not break your fast and can be taken as directed by your healthcare provider with water.

If prescribed medicines need to be taken with food then participants should consult their healthcare practitioner about shifting their eating window, so that all prescribed medications that must be taken with a meal can be done during that 10 hour eating window.

Supplements that are not prescribed by a healthcare provider should be taken during the 10 hour eating window if they contain sweeteners.

If you're stuck on a screen and can't move forward, please try reducing the size of your text by changing the settings for large text on your device. This should allow you to see the button that will take you to the next screen. 

During your fasting window, you shouldn’t eat any food but you can drink beverages that don’t have any calories or sweeteners, including tap, still, and sparkling water, as well as tea (including herbal tea) and coffee without milk, sugar, or sweeteners. Diet soft drinks and hot water with a slice of lemon/orange etc. should be avoided while fasting.  

Anything you eat or drink that is not water, unsweetened black or herbal tea or black coffee would count for your first or last ‘eating’. For example if you had tea with milk at 08:00, you would record 08:00 for your ‘first eating time’. Alternatively if you had a glass of wine at 23:00 after having dinner at 20:00, you would enter 23:00 as your ‘last eating time’.

Yes, you’re free to join the Study at any time after it launches on Monday 24 October. So don’t worry if you can’t start straight away! 

If you know that you won’t be able to eat within a 10 hour window on one day, the best practice is to record your eating times accurately on those days. This is so we can get a realistic picture of how well IF is working, and how easy it is to stick to in the real world.

The same is true if you won't be able to do a 10 hour window for several days, just record your eating times accurately on those days.

Alternatively, you can stop logging in the app if that's easier to do and return when you're ready. 

We understand that people may not always be able to log every day for the Study, so it’s not a problem if you miss a few days - your data is still incredibly useful. You can come back and continue the Study when you’re ready.  However, you’ll rejoin on the most recent day and you won’t be able to retrospectively log your meal times. 

For example, if you miss logging day 4 and 5 of the study and rejoin on day 6 then you’ll be able to log from day 6 onwards but won’t be able to go back and fill in the days you missed.

Yes, you can rejoin and start the Study again later. However, we won’t be able to transfer across your previous data so you’ll need to start from the beginning again. You can also skip a few days of logging if you need to, and rejoin when you’re ready, though you won’t be able fill in data for the days you missed.

You can always refer to the top of the reporting screen in your app which will tell you if you need to eat within the 10 hour window or not. There’s also information on our website that will tell you more about the study.

Immediately after you’ve finished the study you’ll be able to see how intermittent fasting affects your symptoms, mood, energy levels and hunger via an in-app report. Once our scientists have concluded their analysis of the study’s data across all participants, we’ll present our findings back to you.  

Yes, you can change your 10 hour window to whenever suits you throughout the study. Just make sure to log your first and last eating times as usual in the app.

We understand that life can get in the way sometimes, so if you're out late one night please don't worry about delaying when you open your fast the next day. Just choose the 10-hour window that suits you. The focus for this study is on the 10-hour eating window, not the 14 hour fast.

This is a survey we ask participants to fill out both before starting the study and again after finishing the study. It allows our scientists to understand your usual diet and lifestyle habits to give context to the data collected during the Intermittent Fasting Study. The survey will help indicate the impact intermittent fasting may have had on you and whether any aspects of your lifestyle have changed due to the study.

Please answer the survey based on how you are currently eating. We want to see a snapshot of your diet quality for the past month or so.

If you're already intermittently fasting, you can still participate in the study. We suggest that you use this as an opportunity to see how adjusting your eating time window for 2 weeks affects how you feel (your energy, mood, hunger and health symptoms). For example, if you usually eat within 8 hours, you could see how eating within 10 hours affects you. If you don’t want to change your eating window, you can still participate in the study and log whilst fasting intermittently as usual. This data will be helpful for our research and you'll still be able to receive some personalised insights at the end of the Study. 

We understand that it may be difficult to give just one score for these measures as they can fluctuate throughout the day. However, please try to give a general score that relates to how you usually feel. For example, you may have noticed that your mood was a lot lower than usual, or that you felt a lot less hungry than usual.

You can share the study with others who may be interested in participating by clicking ‘share’ at the bottom of the reporting page. They’ll need to download the app and create their own ZOE Health Study account if they don’t already have one.

You can register your interest in the study by filling out your details in the signup form on the Intermittent Fasting webpage. We’ll keep you updated if the study becomes available in your area.

Yes, your daily report will continue to contribute to our COVID research as you’ll log any new symptoms in addition to the Intermittent Fasting Study data.  You can also log any new tests or vaccines in the ‘profile’ tab within the app, which can be found at the bottom right corner of your homepage.