Not yet recruitingNAINTERVENTIONAL

Energy Expenditure and Neuromuscular Function in Young Adult Women With a Naturally Thin Build (LeanErgy)

This research is called 'LeanErgy' and focuses on young adult women who are naturally very thin, meaning they have a low body mass index (BMI under 17.5) but do not have an eating disorder like anorexia. Instead, they have what's known as 'constitutional thinness.' The study aims to understand how these women's bodies use energy, particularly fat, and how their muscles work compared to women of average weight. We want to find out if standard exercise and diet advice needs to be adjusted for them. This will help doctors and specialists offer better, more tailored support to help these women maintain a healthy weight and lifestyle.

At a glance

Status

Not yet recruiting

Phase

Sponsor

Centre Hospitalier Emile Roux

Enrolment target

Start

15 Dec 2025

Estimated completion

15 Feb 2028

Constitutional Thinness

What is this study about?

This study is particularly interested in a group of young women who are naturally very thin, often called having 'constitutional thinness.' This is different from anorexia nervosa, which is an eating disorder. Women with constitutional thinness don't have an eating disorder, often want to gain weight, and have regular periods and healthy hormone levels, unlike those with anorexia. Their bodies are just built differently, often with lower body fat.

The main goal of this study is to understand how these naturally thin women's bodies use energy. We want to look at how their bodies burn fat and how much energy they use when walking. This is important because existing advice on diet and exercise might not be right for everyone, especially for people whose bodies work a bit differently. By understanding their unique energy profiles, we can help develop better, more personalised guidance for them.

We also want to explore how their muscles function. Previous research has shown some differences in muscle strength, but it's unclear if this means their muscles are weaker or if it's just a normal adjustment to having a smaller body. This study will look more closely at muscle function to get a clearer picture. Ultimately, this research aims to provide the best possible support for women with constitutional thinness, helping them stay healthy and strong.

Key takeaways

This study focuses on young women who are naturally very thin, not due to an eating disorder.
It aims to understand how their bodies use energy and how their muscles work.
The research helps to create better, more tailored health and exercise advice.
You would undergo various physical assessments and possibly blood tests.
It could help distinguish 'constitutional thinness' from other causes of low weight.
Participation could help future understanding of this unique body type.

Who may be eligible?

This study is looking for two groups of women aged between 18 and 35 years old. The first group includes young women who are naturally very thin, meaning their Body Mass Index (BMI) is 17.5 or less. The second group is made up of women with an average weight, with a BMI between 20 and 25.

There are certain reasons why someone might not be able to join. For example, if you are pregnant, breastfeeding, or planning to get pregnant, you couldn't take part. We also can't include women who do a lot of intense exercise (more than 3 sessions a week) or who have certain medical conditions like diabetes, heart problems, or other long-term illnesses that might affect the study results. You also couldn't join if you take certain medicines, smoke, drink alcohol regularly, or are on a very strict diet.

Specifically for the very thin women, we need to make sure that their thinness isn't caused by another underlying health problem. We'll check for conditions like Marfan syndrome to ensure that we are studying women with natural 'constitutional thinness' and not a condition that causes thinness.

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 a woman between 18 and 35 years old?
Is your Body Mass Index (BMI) 17.5 or less (for the thin group) or between 20 and 25 (for the average weight group)?
Are you not pregnant, breastfeeding, or planning to get pregnant?
Do you not regularly do intense physical activity (more than 3 times a week)?
Do you not have diabetes, heart problems, or other serious long-term health conditions?
Are you not using certain medications, smoking, drinking alcohol regularly, or on a very strict diet?

Answer every question to see your result.

What does participation involve?

Details about what taking part in this study involves aren't fully described in the brief summary. However, based on the types of measurements mentioned, you would likely need to visit a research facility for several appointments. These visits would probably include tests to see how your body uses energy, such as measuring how you burn fat, and evaluations of how much energy you use when walking. You would also have check-ups to assess your muscle strength and function, which might involve different exercises or equipment. The study may also involve blood tests to check hormone levels. There's no mention of taking new medication, but you would likely need to follow specific instructions about your diet or activity levels before test days. The total duration of your participation, including follow-up appointments, is not specified but would be fully explained by the research team if you are interested.

Potential risks and benefits

Taking part in this study could help advance our understanding of how naturally thin women's bodies work, which could lead to better health advice for them in the future. You might also learn more about your own body's energy use and muscle function. As with any study involving physical assessments and blood tests, there are some potential risks. These could include minor discomfort during exercise tests or from blood draws. The research team will explain all procedures in detail, and you will have the right to withdraw from the study at any time without giving a reason, and this would not affect your medical care.

Locations (1)

Laboratoire AME2P, Université Clermont Auvergne
Verified postcode
Aubière, France

Common questions

What is 'constitutional thinness'?

It means you are naturally very thin (low BMI) but don't have an eating disorder, are generally healthy, and often want to gain weight.

How is this different from anorexia?

Unlike anorexia, women with constitutional thinness have regular periods, healthy hormone levels, and don't have an eating disorder or distorted body image.

What will I have to do in the study?

You'll likely have tests to see how your body uses energy, especially fat, how much energy you use when walking, and how your muscles work.

Will I have to take any new medicines?

No, there's no mention of taking any new medicines as part of this study.

Will this study help me personally?

While the main goal is research, you might learn more about your own body, and the study's findings could lead to better health advice for naturally thin women in the future.

How to find out more

David THIVEL, Director of AME2P Laboratory

david.thivel@uca.fr +0033 4 73 40 76 79 Official trial record

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