RecruitingNAINTERVENTIONAL

Sex Hormones as Regulators of the Age- and Sex-dependent Benefits of Caloric Restriction

This study aims to understand how sex hormones, age, and biological sex influence the results of dieting, especially concerning weight loss and fat reduction. Many people in the UK are overweight or obese, increasing health risks like diabetes and heart disease. While dieting can help, current advice doesn't consider differences between men and women or different age groups. Our previous research suggests women might find it harder to lose weight and fat while dieting. We will study 75 men and women of different ages to see how their bodies respond to diet changes and how hormones play a role. The goal is to improve our understanding of diet and women's health to better tackle obesity and promote healthy aging.

At a glance

Status

Recruiting

Phase

Sponsor

University of Aberdeen

Enrolment target

Start

09 Jul 2025

Estimated completion

01 Dec 2027

Overweight and Obese Adults Healthy

What is this study about?

Many adults in the UK are overweight or obese, which can lead to serious health problems like type 2 diabetes, heart disease, and some cancers. Often, this is because of too much fat around the tummy. Losing weight and reducing body fat through dieting can improve these health issues, for example, by helping to control blood sugar levels.

Currently, advice for losing weight mostly focuses on changing your diet and being more active to burn more calories than you eat. However, this advice doesn't usually take into account whether you are a man or a woman, or how old you are. This is surprising because we know that health outcomes can be quite different for men and women throughout their lives. For instance, menopause can change how women store fat due to shifts in their hormones.

Our earlier research has shown that women might not lose as much weight or body fat as men when they go on a diet. This study wants to dig deeper into these differences, especially focusing on women’s health, by looking at hormones and how the body processes food. We plan to have 75 participants, including younger and older men and women, to carefully measure how their bodies change during a diet. We'll also collect blood and fat samples to see how hormones might explain these differences. The main aim is to gain a better understanding of how diet affects women's health, so we can develop better ways to fight obesity and help everyone age healthily.

Key takeaways

This study explores how age, sex, and hormones impact weight loss from dieting.
It aims to improve weight management advice, particularly for women.
Participants will follow different diets and have their body changes monitored.
Researchers will collect blood and fat samples to study hormones' role.
The goal is to understand how diet affects women's health and fight obesity.

Who may be eligible?

This study is looking for healthy adults between 18 and 65 years old who are overweight or obese. We need both men and women. Specifically, we are looking for younger women (aged 40 or under), younger men (aged 40 or under), women aged 55-65 who have gone through menopause and are not taking hormone replacement therapy (HRT), men aged 55-65, and women aged 55-65 who have gone through menopause and have been taking oestrogen HRT continuously for at least two years.

There are certain reasons why you might not be able to join. For example, if you are pregnant, planning to become pregnant, or breastfeeding. You also can't take part if you have certain medical conditions like diabetes (type 1 or type 2), coeliac disease, or certain psychiatric disorders. If you are a vegetarian or vegan, or currently on a weight-loss program, you won't be able to participate. We also can't include you if you are unable to speak, read, or understand English well enough to give your full consent or if you can't follow a diet that's alcohol-free for six weeks.

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 healthy but considered overweight or obese?
Are you able to speak, read, and understand English well?
Are you willing to avoid alcohol for six weeks?
Are you not currently pregnant, breastfeeding, or planning a pregnancy?
Do you not have diabetes, coeliac disease, or specific psychiatric conditions?

Answer every question to see your result.

What does participation involve?

If you take part in this study, it will involve two main stages. For the first stage, you'll follow your usual diet to help us understand your body's normal functions. For the second stage, you'll follow a specific diet designed to help with weight loss. During the whole study, we will be carefully tracking changes in how your body uses energy and what your body is made of (like fat and muscle). This will involve using special methods like 'doubly-labelled water', which involves drinking a safe, specially-marked water to monitor your metabolism over time.

We will also collect blood samples at various points throughout the study. Additionally, we will collect small samples of fat from your tummy area. These samples will help us understand how your hormones and metabolism are affected by the diets. You will need to commit to an alcohol-free diet for six weeks during the study. The exact number of visits and the full duration of the study will be explained in detail if you decide to inquire further.

Potential risks and benefits

Participating in this study might offer some potential benefits, such as gaining a better understanding of your own body's response to diet and contributing to important research that could help develop more effective weight management strategies, especially for women. Potential risks include the minor discomforts associated with blood draws and fat tissue samples. There's also the commitment required to follow a specific diet and attend appointments. You are free to withdraw from the study at any time, for any reason, without it affecting your medical care.

Locations (1)

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

Rowett Institute, University of Aberdeen
Verified postcode
Aberdeen, United Kingdom· Recruiting

Common questions

What is 'caloric restriction'?

Caloric restriction simply means eating fewer calories than your body uses, which leads to weight loss.

Why are you focusing on women's health?

Our previous research suggests that women might respond differently to dieting compared to men, and we want to understand how hormones and age play a role in these differences, especially around menopause.

What does 'doubly-labelled water' mean?

It's a safe way to measure how many calories your body is burning. You drink a special kind of water, and then we collect samples (like urine) to see how quickly your body uses up the marked water to figure out your energy use.

Will I have to stop drinking alcohol?

Yes, you will need to commit to an alcohol-free diet for a period of six weeks during the study.

What kind of diet will I follow?

The study involves two stages: first, you'll follow your usual diet, then a specific diet designed for weight loss. The exact details will be provided if you are eligible to join.

How to find out more

Alexandra M. Johnstone, Professor

alex.johnstone@abdn.ac.uk 01224 438614 Official trial record

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