We are interested in studying the relationships between physical activity patterns, diet, and blood glucose concentrations in free-living conditions. These results will help us understand how different lifestyle factors, such as activity, diet and sleep, affect glucose profiles measured using a continuous glucose monitor.

We will also study how these factors are impacted by a day of fasting. This will help us better understand the effects of fasting on energy balance and blood glucose control.

What's involved in the study

Baseline lab visit 1

On visit 1, you will visit the laboratory at the University of Bath in a fasted state (i.e., in the morning after waking up) to complete baseline testing lasting approximately 45 minutes. We will ask you to breathe through a tube for 15-30 minutes to see how much energy you use at rest, and complete some basic body measurements such as height, weight, waist and hip circumference, the width at your waist and blood pressure. You will then be asked to complete a brisk walk on the treadmill whilst breathing through the same tube so we can individually calibrate your activity monitor.

Monitoring period

On leaving the lab, you will be provided with an activity monitor, a continuous glucose monitor, a food diary, and body weight scales. We will instruct you on how to wear the activity monitor on your chest and ask that you wear this and record your food intake for two 7-day periods. During this time, we will also ask that you weigh yourself first thing in the morning and just before you go to bed, as well as recording your sleep times.

Lab visit 2

The second lab visit will take place after you complete the first 7-day monitoring period and will last approximately 45 minutes. The visit will involve the same measurements as visit 1, except for the brisk treadmill walk. You will start your second 7-day monitoring period after this visit.

Fasting day

This study also involves one day of fasting immediately before starting one of the 7-day monitoring periods. You will be given sodium and potassium tablets to consume, and you will be allowed to drink water and non-caloric/non-caffeinated beverages as you wish. As a safety precaution we ask that you do not drive your car if you own one. We are more than happy to cover the cost of public transport on that day. Aside from that, you are free to go about your daily activities as you would on any other day.

Eligibility

To be eligible to participate in this study, you must be aged 18-65 years old.

Exclusion criteria:

• Any reported condition or behaviour deemed either to pose an undue personal risk to the participant or introduce bias
• Any diagnosed metabolic disease (e.g., type 1 or type 2 diabetes)
• Any reported use of substances that may pose an undue personal risk to the participants or introduce bias into the experiment
• Lifestyle not conforming to standard sleep-wake cycle (e.g., shift worker)
• Pregnancy/breastfeeding
• History of eating disorders (e.g., anorexia)
• Any reported recent (<6 months) change in body mass (± 3%)
• History of migraines and or headaches

What you'll get for taking part

We are not able to offer direct benefits for taking part. However, you will receive detailed feedback about your glucose levels, physical activity energy expenditure and dietary intake over four weeks.

Confidentiality

We will need to use information from you for this research project. When you enrol to the study you will be assigned a unique study code to protect anonymity such that nobody outside of the research team will be able to work out who you are from the reports that we write. We will only use information that we need for the research study. Any identifiable personal data will be kept in a locked cabinet in a locked room, or on a password-protected file on the University’s servers, in accordance with the current UK Data Protection regulations. Throughout the study all documents will only contain your unique study code, so that people who do not need to know who you are will not be able to see your name or contact details.¹