Actively Recruiting

Phase Not Applicable
Age: 18Years - 65Years
All Genders
Healthy Volunteers
ID07065643

GendAge Weight Loss Study: Sex Hormones as Regulators of the Age- and Sex-dependent Benefits of Caloric Restriction

Led by University of Aberdeen · Updated on 2025-07-18

75

Participants Needed

1

Research Sites

N/A

Total Duration

On this page

Sponsors

U

University of Aberdeen

Lead Sponsor

U

University of Edinburgh

Collaborating Sponsor

AI-Summary

What this Trial Is About

Researchers are investigating how sex hormones influence the effects of calorie restriction on obesity, with a focus on age- and sex-related differences. The study aims to better understand how men and women, especially women around menopause, respond differently to dieting and fat loss. This research involves healthy overweight or obese adults and seeks to improve public health guidance for managing weight and promoting healthy aging. Participants will undergo two phases: first, a 3-day maintenance diet tailored to their energy needs, followed by a 6-week calorie-restricted high-protein diet designed to reduce calorie intake gradually. The study includes groups of younger and older men and women, including menopausal women with and without hormone replacement therapy. Body composition and energy expenditure will be closely monitored using advanced techniques, and blood and fat tissue samples will be collected to study hormone effects. During the 53-day study period, participants will have frequent assessments including weight measurements three times a week, energy expenditure tracking, and blood tests at multiple time points. Researchers will measure changes in body mass, metabolic rate, body fat percentage, hormone concentrations, and other metabolic markers. The study also monitors bone mineral content and body water levels. This comprehensive approach aims to clarify how calorie restriction affects weight loss and metabolism across different age and sex groups.

CONDITIONS

Brief Title

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

Who Can Participate

Age: 18Years - 65Years
All Genders
Healthy Volunteers

Eligibility Criteria

Eligible

You may qualify if you...

  • Adults aged 18 to 65 years who are healthy but overweight or obese with a BMI between 27 and 45
  • Women aged 40 or younger
  • Men aged 40 or younger
  • Women aged 55 to 65 years in menopause and not taking hormone replacement therapy (HRT)
  • Women aged 55 to 65 years in menopause and continuously taking oestrogen HRT for 24 months
  • Men aged 55 to 65 years
Not Eligible

You will not qualify if you...

  • Current use of weight loss medications (e.g., GLP agonists), beta-blockers, antihistamines, antipsychotics, benzodiazepines, barbiturates, melatonin, Ritalin, modafinil, soporifics, hypnotics, antiepileptic drugs, or diabetes medications (e.g., metformin or insulin)
  • Females who are pregnant, planning to become pregnant, or breastfeeding
  • Diagnosed with coeliac disease, gluten intolerance, or food allergy
  • Diagnosed with type 1 or type 2 diabetes
  • Suffering from psychiatric disorders or substance abuse
  • Following a vegetarian or vegan diet
  • Currently on a weight loss program or have had gastric band/reduction surgery
  • Participating in another research study
  • Unsuitable veins for blood sampling
  • Unable to fluently speak, read, and understand English
  • Unable to comply with an alcohol-free diet for 6 weeks
  • Unable to give fully informed consent

AI-Screening

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Your Study Journey

Screening

Duration - 2 to 4 weeks

Participants are screened for eligibility to participate in the trial.

1 visit (in-person)

Phase 1 - Maintenance Diet

Duration - 3 days

Participants follow a 3-day maintenance diet with fixed macronutrient composition, fed to energy requirements.

Visits as needed to monitor diet adherence

Phase 2 - Weight Loss Diet

Duration - 6 weeks

Participants follow a 6-week calorie restricted high protein diet with stepwise calorie reduction at weeks 3 and 5.

1 baseline visit and approximately 3 visits per week throughout the intervention

Trial Site Locations

Total: 1 location

1

Rowett Institute, University of Aberdeen

Aberdeen, United Kingdom

Actively Recruiting

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Research Team

A

Alexandra M. Johnstone, Professor

M

Marta Lonnie, Dr

How is the study designed?

Study Type

INTERVENTIONAL

Masking

NONE

Allocation

NON_RANDOMIZED

Model

FACTORIAL

Primary Purpose

BASIC_SCIENCE

Number of Arms

5

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