We are currently recruiting for a randomised controlled trial. Participants will be following a diet plan for 12 weeks and undergo laboratory testing at three points within the trial period.

We will be comparing the diets that people currently eat against the global health guidelines that currently advocate a reduction in dietary sugar intake from current levels, and for fat intake to be consumed in moderation. We will also be comparing the diets that people currently eat against a low carbohydrate diet.

Excess dietary sugar and fat intake are known to be associated with metabolic diseases like obesity and type 2 diabetes. There is also an increasing school of thought that low carbohydrate diets are beneficial for metabolic health. The effect these diets have on components of energy balance (especially physical activity) has not been comprehensively studied.

What's involved in the study

You will be asked to stick to a diet for 12 weeks. You will be randomly allocated one of 3 diets. The three diets under investigation will:

• contain a low amount of sugar
• contain a normal (moderate) amount of sugar
• contain low amount of carbohydrate/high fat

We will focus on aspects of health including body composition, physical activity, energy intake, circulating blood hormone (e.g. insulin) and metabolite (e.g. glucose) concentrations, genetic changes in muscle and fat tissue, and gut microbiome health.

To participate in the study, you will be asked to complete 3 trials and some preliminary measures; testing at baseline, at 4 weeks, and at 12 weeks. Each trial will be split across 2 days, with the first day lasting approximately 2 hours in the afternoon and the second day lasting approximately 5 hours in the morning. The first trial will take place at the start of the study, then trials will be repeated at 4 weeks and 12 weeks once the study is underway. The procedures involved in the study include blood sampling and tissue biopsies.

Eligibility

To be eligible to participate in this study, you must:

• be male or female, healthy, and aged between 18-65 years old
• have a body mass index between 18.5 and 29.9 kg/m(squared)

Some things that may make you ineligible for the study include:

• a diagnosed metabolic disease (e.g. type 1 or type 2 diabetes)
• use of substances which may pose undue personal risk to you or introduce bias into the study
• if you do not conform to a standard sleep-wake cycle (e.g. working night shifts)
• any reported change of body mass >3% in the last 6 months
• use of antibiotics in the last 3 months
• use of probiotic products in the last month

What you'll get for taking part

The main benefit of taking part in this study is that you will receive detailed feedback about your physiological health. The feedback will include a detailed analysis of your diet, including calorie intake and macronutrient composition, detailed breakdown of your metabolic rate and energy expenditure, feedback on your body composition, feedback on your circulating metabolites and hormones in your blood.

You will be partially reimbursed for groceries for 12 weeks and will be making a potentially invaluable contribution to scientific knowledge that will pioneer new findings in this area of research.

Due to the exploratory nature of the diets, we are not able to claim the exact health benefits when allocated to each of the diets on the study.

Confidentiality

All identifiable data will be stored in a locked cabinet or in a password protected spreadsheet on the University’s servers. For this reason, only the lead investigator and principal supervisor will be able to identify participants. As a participant, you will be able to access your own data upon request.