Brief Summary

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.

Trial Health

On Track

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Enrollment

participants targeted

Target at P50-P75 for not_applicable

Timeline

19mo left

Started Jul 2025

Typical duration for not_applicable

Geographic Reach

1 country

1 active site

Status

recruiting

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

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Study Timeline

Key milestones and dates

2.4 years study duration

Study Progress35%

Jul 2025Dec 2027

First Submitted

Initial submission to the registry

July 3, 2025

Completed

6 days until next milestone

Study Start

First participant enrolled

July 9, 2025

Completed

6 days until next milestone

First Posted

Study publicly available on registry

July 15, 2025

Completed

2.4 years until next milestone

Primary Completion

Last participant's last visit for primary outcome

December 1, 2027

Expected

Same day until next milestone

Study Completion

Last participant's last visit for all outcomes

December 1, 2027

Last Updated

July 18, 2025

Status Verified

July 1, 2025

Enrollment Period

2.4 years

First QC Date

July 3, 2025

Last Update Submit

July 17, 2025

Conditions

Overweight and Obese Adults Healthy

Keywords

caloric restrictionlow calorie dietmenopauseoverweightobesityweigh lossageingenergy expenditurebody composition

Outcome Measures

Primary Outcomes (2)

Change in body mass expressed as weight in kilograms (kg)
Measured using digital scale
From baseline (day 1) to end of intervention (day 53); additional measurements taken three times a week throughout the intervention duration
Change in energy expenditure expressed in kilocalories per day (kcal/day)
Measured using stable isotope method - doubly labelled water (DLW) - with urine sample collection
From day 11 (start of the calorie-restricted diet) to the end of the intervention (day 52); with additional doses consumed on day 25 and 39

Secondary Outcomes (12)

Change in resting metabolic rate (RMR) expressed in kcal/day
From day 8 (start of the maintenance diet) to end of the intervention (day 53)
Change in bone mineral content in grams (g)
From day 8 (start of the maintenance diet) to end of the intervention (day 53)
Change in total body water (TBW) in litres (l)
From day 11 (start of the calorie-restricted diet) to end of the intervention (day 53)
Change in total body density expressed in litres (l)
From day 8 (start of the maintenance diet) to end of the intervention (day 53)
Change in body fat-mass percentage (%)
From day 8 (start of the maintenance diet) to end of the intervention (day 53)
+7 more secondary outcomes

Other Outcomes (7)

Change in glycaemic control in response to caloric restriction diet
Every day of the study (days 1-53)
Change in fasting concentration of glucose
From day 8 (start of the maintenance diet) to end of the intervention (day 53)
Change in fasting concentration of ketones
From day 8 (start of the maintenance diet) to end of the intervention (day 53)
+4 more other outcomes