Not yet recruitingNAINTERVENTIONAL

Dissecting the Roles of High-quality Diets and Ultra Processed Foods on Cardiometabolic Health

This study aims to understand how highly processed foods (called UPF) affect your heart and overall body health. There's a lot of debate about these foods, and we want to find out if the processing itself has an effect, even if the diet is generally good for you. We're especially interested in this question when people are already eating a healthy, plant-based diet. Participants in Ireland (North and South) will follow specific diets – either a healthy plant-based diet that includes some highly processed foods, or one that avoids them. By comparing these groups, researchers hope to see if highly processed foods have their own impact on things like blood sugar and cholesterol, helping us give clearer advice about healthy eating.

At a glance

Status

Not yet recruiting

Phase

Sponsor

Queen's University, Belfast

Enrolment target

330

Start

01 Oct 2026

Estimated completion

01 Jun 2029

Cardiometabolic Risk Factors

What is this study about?

This research project is looking into how highly processed foods, which we call UPF for short, might affect your health, especially your heart and how your body uses energy (what we call cardiometabolic health). There's a lot of conversation and some disagreement about whether these types of foods are bad for you, and if so, why. A big question we want to answer is: if someone is already eating a healthy diet, does it matter if some of those foods are highly processed?

To find this out, we're going to compare different diets. All participants will be aiming to eat a healthy diet that mainly includes plant-based foods. Some people will have this healthy diet that also includes highly processed foods, while others will have the same healthy diet but will avoid highly processed foods. By doing this, we hope to see if the way food is processed has its own effect on your health, separate from whether the diet is generally good or bad.

We'll be looking at important health markers like your blood sugar levels and cholesterol. The results of this study could help us understand more clearly what makes a diet truly healthy and provide better advice for everyone in the UK about what to eat to keep their hearts and bodies well.

Key takeaways

This study investigates if highly processed foods (UPF) have an impact on health even within an otherwise healthy diet.
It focuses on heart and metabolic health, looking at markers like blood sugar and cholesterol.
Participants will follow different versions of a healthy, plant-based diet.
The study aims to provide clearer advice on diet and food processing for the public.
Participation will involve diet changes and health check-ups over 4-5 months.
It is for adults aged 18-65 in generally good health.

Who may be eligible?

To be considered for this study, you need to be a man or woman between the ages of 18 and 65. You should generally be in good health and have a body mass index (BMI) below 35. You'll also need to be able to fully understand and agree to take part in the study.

However, there are certain reasons why you wouldn't be able to join. If you have conditions like diabetes, heart disease (CVD), or any type of cancer (except for a very common skin cancer called basal cell), you won't be eligible. Also, if you are pregnant, breastfeeding, or have any other health condition or dietary needs that would make it very difficult for you to follow the study's diets, you wouldn't be able to participate.

Could this study suit you?

Answer these quick questions to see if you may be eligible. This is a guide only — the research team makes the final call.

Are you between 18 and 65 years old?
Are you generally in good health, without major illnesses like diabetes or heart disease?
Is your BMI (Body Mass Index) below 35?
Are you able to follow specific diet plans for several months?
Are you not pregnant or breastfeeding?

Answer every question to see your result.

What does participation involve?

If you take part, the study will involve different stages. There's an initial 6-week run-in phase for some people to help them reach a healthy plant-based diet, while others who already eat well will move straight to the main study. The main study itself will last for 4 months. Throughout these phases, you'll be asked to follow a specific diet plan. This means you will either be eating a healthy plant-based diet that includes some highly processed foods, or the same healthy plant-based diet but without highly processed foods.

You won't be given any special medication as part of this study. Your diet will be the main 'intervention'. Researchers will regularly check your health, likely through blood tests to measure things like blood sugar and cholesterol, and possibly other body measurements. You'll have visits to the study clinic for these assessments. The total time you'll be involved in the study, if you go through both phases, will be approximately 5 and a half months.

Potential risks and benefits

Taking part in this study could offer some potential benefits, such as receiving support to improve your diet, which might lead to better overall health. We hope the insights gained will improve future dietary advice for everyone. As with any study involving dietary changes, there might be some minor discomforts or changes in digestion as your body adjusts to new foods. Researchers will monitor your health closely, and dietary advice will be carefully managed. You are free to withdraw from the study at any time, for any reason, without it affecting your medical care.

Locations (2)

Some site locations are approximate. We're improving this — please verify with the trial team before travelling.

University College Dublin
Verified postcode
Dublin, Ireland
Centre for Public Health, Queen's University Belfast
Verified postcode
Belfast, United Kingdom

Common questions

What are 'highly processed foods'?

These are foods that have gone through many industrial steps, often containing ingredients you wouldn't usually find in a home kitchen, like artificial colours, flavours, or preservatives. Examples include many packaged snacks, sugary drinks, and ready meals.

What does 'cardiometabolic health' mean?

It refers to the health of your heart and blood vessels, and how your body processes sugar and fats. This includes things like your blood pressure, cholesterol, and blood sugar levels.

Will I have to eat only plant-based foods?

The study uses healthy plant-based diets as a base. If you have low adherence to a plant-based diet, you'll get support to move towards one. Then, you'll either have a high-UPF or low-UPF version of that diet.

Where does the study take place?

The main part of the study will be conducted in Ireland, covering both Northern Ireland and the Republic of Ireland.

Will I know which diet I'm on?

Yes, you will know whether you are assigned to the group eating a healthy plant-based diet with highly processed foods, or the group with the healthy plant-based diet avoiding them.

How to find out more

Prof. Jayne Woodside, PhD

j.woodside@qub.ac.uk +4402890 978942 Official trial record

Always speak to your GP or specialist before deciding to take part in a study.