RecruitingInterventional

Plant Your Health: a randomised controlled trial comparing vegan, vegetarian and omnivorous diets in younger to middle-aged adults with overweight or obesity

Plant-based diets are becoming popular, but we still need high-quality research to see how they protect our hearts over the long term. The Plant Your Health study is looking at whether switching to a vegan or vegetarian diet lowers 'bad' LDL cholesterol and improves overall wellbeing over 12 months. The trial is open to adults aged 18 to 50 who carry extra weight and currently eat meat and dairy most days. Participants are randomly placed into one of three groups: a vegan diet, a vegetarian diet, or their normal meat-eating diet. Those switching diets will receive regular coaching and support from a dietitian. Everyone attends three hospital visits in Leicester over a year for blood tests and body scans, and all participants receive supermarket vouchers to help cover the cost of their food.

At a glance

Status

Recruiting

Sponsor

University of Leicester

Enrolment target

450

Start

01 Aug 2026

Estimated completion

30 Sep 2027

Overweight and obesity and associated cardiometabolic risk factors in adults

What is this study about?

Many people choose to eat less meat for their health or the environment. Eating plenty of plant foods is linked to better heart health and lower rates of type 2 diabetes. However, doctors still need more long-term evidence to understand if switching to a vegetarian or vegan diet directly improves cholesterol, blood pressure, and body fat over a full year.

The Plant Your Health study aims to answer this question. Researchers will compare three groups of adults who carry extra weight: one group eating a vegan diet (no animal foods), one eating a vegetarian diet (dairy and eggs allowed, but no meat), and one continuing their normal diet with meat. By tracking everyone over 12 months, the team can see real-world changes in health markers, energy levels, and daily wellbeing.

Taking part in this study helps scientists understand whether plant-based diets are safe, practical, and effective over the long haul. The results could help shape future NHS guidance on how diet can help people manage their weight and keep their hearts healthy.

Key takeaways

A 12-month UK study looking at how vegan, vegetarian, and meat-eating diets affect heart health.
Open to adults aged 18 to 50 who carry extra weight and currently eat meat regularly.
Participants are randomly assigned to one of three eating plans.
Includes expert support from a dietitian and supermarket vouchers to help with food shopping.
Requires three appointments at the Leicester Diabetes Centre over the course of the year.

Who may be eligible?

This study is designed for adults aged 18 to 50 who carry excess weight (a body mass index of 25 to 40, or 23 to 40 for people from ethnic minority backgrounds). To join, your weight must have stayed fairly steady over the past six months. You also need to be a regular meat and dairy eater, having them at least five days a week, and you must be willing to be placed into any of the three diet groups.

You cannot take part if you have type 1 or type 2 diabetes, or if you have serious long-term conditions affecting your liver, kidneys, or digestive system (such as coeliac disease or Crohn's disease). You will also be excluded if you take cholesterol-lowering medicines like statins, are receiving active treatment for cancer, have had heart problems in the last six months, or have a severe food allergy or eating disorder.

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.

I am between 18 and 50 years old.
I have a BMI between 25 and 40 (or 23 to 40 if from an ethnic minority background).
I currently eat meat and dairy foods at least five days a week.
My weight has stayed mostly stable for the past six months.
I do not have diabetes or serious kidney, liver, or gut conditions.
I am not taking statins or other cholesterol-lowering treatments.

Answer every question to see your result.

What does participation involve?

Taking part in the study lasts for 12 months. After joining, a computer randomly assigns you to follow either a vegan diet, a vegetarian diet, or your usual diet with meat. If you are placed in a plant-based group, you will get personal guidance and regular coaching from a study dietitian or nutritionist to help you plan your meals.

You will need to visit the Leicester Diabetes Centre three times: at the start, at six months, and at 12 months. Each visit lasts around two and a half to three hours. During these visits, the team will check your blood pressure, take blood samples, measure your fitness, and carry out a DXA body scan to look at your body fat and muscle. You will also wear an activity tracker and fill in brief food diaries at home. All participants receive supermarket vouchers to help support food shopping.

Potential risks and benefits

You may benefit from expert dietary support and notice improvements in your heart health, weight, or energy, although benefits cannot be guaranteed. Everyone receives supermarket vouchers, and those keeping their usual diet will get healthy eating resources once the study ends. Risks are generally mild: blood tests can cause brief pain or bruising, and changing what you eat may cause temporary tummy bloating while your body adjusts. The DXA scan uses a very tiny amount of radiation, with an extremely small risk to health. Taking part is completely voluntary, and you are free to stop and leave the trial at any time without giving a reason.

Locations (1)

Leicester Diabetes Centre
Approximate
Leicester, England

Common questions

Can I pick which diet I follow?

No. A computer randomly decides which group you join so that the study results remain fair and unbiased. You must be happy to follow any of the three diets.

Do I have to pay for my own food?

You buy your own groceries as normal, but the study provides supermarket vouchers to help you cover the cost of your food during the year.

Where do the clinic visits happen?

All three visits take place in person at the Leicester Diabetes Centre.

What happens if I struggle with the new diet?

If you are in the vegan or vegetarian group, a study dietitian or nutritionist will give you regular coaching, tips, and support to help you stay on track.

Can I leave the study if I change my mind?

Yes. You have the right to withdraw from the trial at any point, and your usual healthcare will not be affected in any way.

How to find out more

Claire Bordoli

Uhl-tr.plantyourhealth@nhs.net +44 (0) 116 258 8070 Official trial record

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