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

NCT ID: NCT07065643

Last Updated: 2025-07-18

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

RECRUITING

Clinical Phase

NA

Total Enrollment

75 participants

Study Classification

INTERVENTIONAL

Study Start Date

2025-07-09

Study Completion Date

2027-12-31

Brief Summary

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Obesity increases the risk of type 2 diabetes, cardiovascular disease, and certain cancers, primarily due to elevated abdominal fat storage. With nearly two-thirds of the UK population living with overweight or obesity, there is an urgent necessity for evidence-based public health guidance to promote healthy weight. Calorie deficit can facilitate weight loss and body fat reduction, leading to health benefits, such as improved blood glucose control. Current weight management advice centres on lifestyle modification, incorporating changes to diet and physical activity to support a calorie deficit. However, existing dieting recommendations fail to consider gender or age. This is a surprising oversight, as it is well established that health outcomes vary significantly between men and women across the lifespan. Further, the menopause may have an impact on fat storage linked to changes in sex hormones. Our recent research, involving both mice and humans, has indicated that females are less responsive to weight loss and fat reduction during dieting. This study aims to understand endocrine and metabolic sex-based differences in obesity and calorie restriction, with a particular focus on women's health. We plan to conduct a diet study with 75 participants, encompassing both younger and older men and women, to monitor changes in energy expenditure and body composition using gold-standard techniques, such as doubly-labelled water. Blood and abdominal fat tissue samples will be collected to investigate how sex hormones might elucidate these differences. The aim of the study is to enhance our understanding of diet and women's health to combat obesity and promote healthy ageing.

Detailed Description

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Conditions

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Overweight and Obese Adults Healthy

Study Design

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Allocation Method

NON_RANDOMIZED

Intervention Model

FACTORIAL

Primary Study Purpose

BASIC_SCIENCE

Blinding Strategy

NONE

Study Groups

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Young women

Age: 18 to 40 years old

Group Type EXPERIMENTAL

Phase 1 - Maintenance Diet

Intervention Type OTHER

3d maintenance diet (MT, fixed macronutrient composition of 15% protein, 30% fat and 55% CHO), fed to energy requirements (1.3 X RMR)

Phase 2 - Weight loss diet

Intervention Type OTHER

6 week calorie restricted high protein diet (CR, fixed macronutrient composition as 30% protein, 35% fat and 35% CHO) fed to energy requirements \[0.8 X Resting Metabolic Rate (RMR)\], with stepwise reduction of 100kcal/d at week 3 and 5

Young men

Age: 18 to 40 years old

Group Type ACTIVE_COMPARATOR

Phase 1 - Maintenance Diet

Intervention Type OTHER

3d maintenance diet (MT, fixed macronutrient composition of 15% protein, 30% fat and 55% CHO), fed to energy requirements (1.3 X RMR)

Phase 2 - Weight loss diet

Intervention Type OTHER

6 week calorie restricted high protein diet (CR, fixed macronutrient composition as 30% protein, 35% fat and 35% CHO) fed to energy requirements \[0.8 X Resting Metabolic Rate (RMR)\], with stepwise reduction of 100kcal/d at week 3 and 5

Older women (menopause & no-HRT)

Age 55-65 years, in menopause, not taking Hormonal Replacement Therapy (HRT)

Group Type EXPERIMENTAL

Phase 1 - Maintenance Diet

Intervention Type OTHER

3d maintenance diet (MT, fixed macronutrient composition of 15% protein, 30% fat and 55% CHO), fed to energy requirements (1.3 X RMR)

Phase 2 - Weight loss diet

Intervention Type OTHER

6 week calorie restricted high protein diet (CR, fixed macronutrient composition as 30% protein, 35% fat and 35% CHO) fed to energy requirements \[0.8 X Resting Metabolic Rate (RMR)\], with stepwise reduction of 100kcal/d at week 3 and 5

Older women (menopause & HRT)

Age 55-65 years, in menopause, who have continuously taken oestrogen HRT for 24 months

Group Type EXPERIMENTAL

Phase 1 - Maintenance Diet

Intervention Type OTHER

3d maintenance diet (MT, fixed macronutrient composition of 15% protein, 30% fat and 55% CHO), fed to energy requirements (1.3 X RMR)

Phase 2 - Weight loss diet

Intervention Type OTHER

6 week calorie restricted high protein diet (CR, fixed macronutrient composition as 30% protein, 35% fat and 35% CHO) fed to energy requirements \[0.8 X Resting Metabolic Rate (RMR)\], with stepwise reduction of 100kcal/d at week 3 and 5

Older men

Age 55-65 years

Group Type ACTIVE_COMPARATOR

Phase 1 - Maintenance Diet

Intervention Type OTHER

3d maintenance diet (MT, fixed macronutrient composition of 15% protein, 30% fat and 55% CHO), fed to energy requirements (1.3 X RMR)

Phase 2 - Weight loss diet

Intervention Type OTHER

6 week calorie restricted high protein diet (CR, fixed macronutrient composition as 30% protein, 35% fat and 35% CHO) fed to energy requirements \[0.8 X Resting Metabolic Rate (RMR)\], with stepwise reduction of 100kcal/d at week 3 and 5

Interventions

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Phase 1 - Maintenance Diet

3d maintenance diet (MT, fixed macronutrient composition of 15% protein, 30% fat and 55% CHO), fed to energy requirements (1.3 X RMR)

Intervention Type OTHER

Phase 2 - Weight loss diet

6 week calorie restricted high protein diet (CR, fixed macronutrient composition as 30% protein, 35% fat and 35% CHO) fed to energy requirements \[0.8 X Resting Metabolic Rate (RMR)\], with stepwise reduction of 100kcal/d at week 3 and 5

Intervention Type OTHER

Eligibility Criteria

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Inclusion Criteria

* Adults (aged over 18years) who are healthy but overweight/obese (BMI 27-45kg/m2) males and females as:
* 15 women (age 40 or less years)
* 15 men (age 40 or less years)
* 15 women (age 55-65 years) in menopause\*; not taking Hormone Replacement Therapy (HRT)
* 15 men (age 55-65 years)
* 15 women (age 55-65 years) in menopause; taking HRT\*\*

Exclusion Criteria

Potential volunteers will be asked to fill in a health questionnaire at the screening visit to assess their suitability for the study. This information will allow us to exclude participants.


• weight loss medication (e.g. GLP agonists), β-blockers, antihistamines, antipsychotics, benzodiazepines, barbiturates, melatonin, Ritalin, modafinil, soporifics, hypnotics, antiepileptic drugs, diabetes medication (e.g. metformin or insulin).


* Females who are planning to be pregnant, are pregnant or are breastfeeding
* Anyone with coeliac disease or gluten intolerance or food allergy
* Anyone with diagnosed T1 or T2 diabetes
* Anyone suffering from a psychiatric disorder or any type of substance abuse


* Anyone following a vegetarian or vegan diet
* Anyone currently following a weight loss programme (that may be affecting lifestyle, physical activity \& diet) or undergone gastric band/reduction surgery; including GLP agonist (e.g. Semaglutide injection, Ozempic®).
* Anyone currently participating in another research study
* Anyone with unsuitable veins for blood sampling
* Anyone who is unable to fluently speak, read and understand English
* Anyone who is unable to comply to an alcohol-free diet for 6 weeks
* Anyone unable to give fully informed consent
Minimum Eligible Age

18 Years

Maximum Eligible Age

65 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

Yes

Sponsors

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University of Edinburgh

OTHER

Sponsor Role collaborator

University of Aberdeen

OTHER

Sponsor Role lead

Responsible Party

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Responsibility Role SPONSOR

Principal Investigators

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Alexandra M Johnstone, Professor

Role: PRINCIPAL_INVESTIGATOR

Rowett Institute, University of Aberdeen

Locations

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Rowett Institute, University of Aberdeen

Aberdeen, , United Kingdom

Site Status RECRUITING

Countries

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United Kingdom

Central Contacts

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Alexandra M. Johnstone, Professor

Role: CONTACT

01224 438614

Marta Lonnie, Dr

Role: CONTACT

Facility Contacts

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Alexandra M Johnstone, Professor

Role: primary

01224 438614

Claire Fyfe

Role: backup

01124 438753

Related Links

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Other Identifiers

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2-034-25

Identifier Type: OTHER_GRANT

Identifier Source: secondary_id

822

Identifier Type: -

Identifier Source: org_study_id

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