How diet influences our health

This project is aiming to understand how the amounts of carbohydrate, fat, and sugar in our diet influences our health. We are looking primarily at energy balance (energy intake and energy expenditure) and the effects our diet has on physical activity levels. We are also interested in how diets varying in carbohydrate, fat, and sugar influence metabolic health and the gut microbiome.

Study Design

The experimental work will begin in October 2017 and should be completed by March 2022. We are interested in the effect of three diets:

• Moderate sugar - where carbohydrate makes up 50% of energy intake, sugar makes up 20%, and fat makes up 35%.
• Low sugar - where carbohydrate makes up 50% of energy intake, sugar makes up less than 5%, and fat makes up 35%.
• Low carbohydrate - where carbohydrate makes up less than 8% of energy intake (restricted to 50 g per day), sugar makes up less than 5%, and fat makes up 77%.

This project will measure energy intake and energy expenditure using a range of laboratory techniques and medical devices. Various samples, including blood samples and tissue samples (from fat and muscle), will be obtained to understand the impact of these diets on our metabolic health.

Diet Manipulation

The moderate sugar diet is designed to represent a typical diet consumed by humans today. The low sugar diet follows the government guidelines published in 2015 to reduce sugar intake to less than 5% of overall calories. The low-carbohydrate diet can also be termed a 'ketogenic' diet, and we are investigating this because there are limited data on the effects of this on energy balance and metabolic health in healthy humans.

Acute Phase

We will assess the responses to diet manipulation across a 24-hour period. This will give us an understanding of the metabolic effects of each meal, and 24-hours of each diet, which will help to explain any longer-term changes.

Intervention Phase

We will assess the responses to diet manipulation across 4- and 12-weeks. This will allows us to understand how the body reacts to each diet in the longer-term, including changes in energy balance and body composition, but also metabolic health and changes to the gut microbiome.

Recruitment

We are looking for healthy people between the ages of 18-65 years, with a body mass index between 18.5 and 29.9 kg/m². A full list of eligibility criteria can be found on our recruitment page.

Funding

This project is funded by:

• The Rank Prize Funds
• University of Bath
• Kenniscentrum Suiker and Voeding

Project Team

University of Bath

• Aaron Hengist
• Russell Davies
• Dr Françoise Koumanov
• Professor James Betts
• Dr Jean-Philippe Walhin
• Professor Dylan Thompson
• Dr Javier Gonzalez

Maastricht University

• Professor Luc van Loon

University of Bristol

• Professor Peter Rogers
• Professor Jeff Bunstrom