Focus on Fibre Study

Not Applicable

Terminated

• Conditions: Appetitive Behavior
• Interventions: Other: Phase 1 - Control; Other: Phase 2 - High Fibre; Other: Phase 3 - Low Fibre

• Registration Number: NCT05449665
• Lead Sponsor: University of Aberdeen

Brief Summary

The investigators present a diet intervention study, to be conducted as a within-subject design, with all food and beverages provided, to allow ad libitum feeding to assess impact of diet change on appetite response. The diets will vary in fibre content and type. This study will allow assessment of the physiological impact of dietary fibre on markers of appetite control for body weight, measured from plasma gut hormones. The investigators propose to recruit participants with a poor diet quality (low habitual fibre intake) to additionally examine the time-course of adaptation of the gut microbiome (measured in faecal samples), whilst assessing the impact of added fibre on body weight and subjective appetite scores. This approach is to address the impact of dietary fibre in people living with obesity and food inequalities. The investigators will assess physiological bio-markers of appetite control and their contribution to the development of a gut ecosystem that promotes health. A subsequent period of return to a low fibre feeding will allow assessment of durability of response.

Detailed Description

Not available

Study Timeline

• Study Start: 2022-06-14
• Study First Submitted: 2022-06-17
• Study First Submitted QC: 2022-07-04
• Study First Posted: 2022-07-08
• Primary Completion: 2023-12-31
• Study Completion: 2023-12-31
• Status Verified: 2024-05
• Last Update Submitted: 2024-05-08
• Last Update Posted: 2024-05-10

Recruitment & Eligibility

• Status: TERMINATED
• Sex: All
• Target Recruitment: 7

Inclusion Criteria

• healthy but overweight/obese (BMI 28-40kg/m2) males and females (post-menopausal, using the oral contraceptive pill or some form of hormonal contraceptive)
• low habitual fibre intake (<10g/day)

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Exclusion Criteria

Medication exclusion criteria:

• antibiotic use (within the past 3 months due to impact on gut microbiota)
• statins (current)
• aspirin or other NSAIDs or anti-coagulants (current)
• anti-depressants (current)
• smoking or vaping

Medical exclusion criteria:

• Females who are planning to be pregnant, are pregnant or are breastfeeding
• Anyone with food allergies, self-reported food sensitivity or intolerance
• Anyone with coeliac disease or gluten intolerance
• Anyone taking medication which may affect their appetite
• Anyone with an eating disorder
• Anyone with diabetes
• Anyone with a gastrointestinal disorder, kidney disease, liver disease or gout
• Anyone suffering from a psychiatric disorder or any type of substance abuse
• Anyone suffering from unregulated thyroid disease

Other exclusion criteria:

• Anyone following a vegetarian or vegan diet
• Anyone following a weight loss programme (that may be affecting lifestyle, physical activity & diet)
• 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

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Study & Design

• Study Type: INTERVENTIONAL
• Study Design: SINGLE_GROUP

Arm && Interventions

Group	Intervention	Description
Control - High Fibre - Low Fibre (CTRL - HF - LF)	Phase 1 - Control	* Phase 1 - CTRL: Control diet with moderate fibre consumption for 13days. * Phase 2 - HF: ad libitum consumption of HF meals for 13days. * Phase 3 - LF: ad libitum consumption of LF meals for 13days.
Control - High Fibre - Low Fibre (CTRL - HF - LF)	Phase 3 - Low Fibre	* Phase 1 - CTRL: Control diet with moderate fibre consumption for 13days. * Phase 2 - HF: ad libitum consumption of HF meals for 13days. * Phase 3 - LF: ad libitum consumption of LF meals for 13days.
Control - High Fibre - Low Fibre (CTRL - HF - LF)	Phase 2 - High Fibre	* Phase 1 - CTRL: Control diet with moderate fibre consumption for 13days. * Phase 2 - HF: ad libitum consumption of HF meals for 13days. * Phase 3 - LF: ad libitum consumption of LF meals for 13days.

Primary Outcome Measures

Name	Time	Method
Change in gut hormones to assess appetite response to dietary fibre	At baseline and end of each arm (study days 0, 14, 28 and 42)	measured by acute and chronic changes in plasma ghrelin and peptide YY (PYY)
Change in subjective hunger to assess appetite response to dietary fibre	At baseline and end of each arm (study days 0, 14, 28 and 42)	measured by acute and chronic changes in appetite using visual analogue scale questionnaires

Secondary Outcome Measures

Name	Time	Method
Change in gut metabolites (from faecal samples) in response to dietary fibre	At baseline and end of each arm (study days 0, 14, 28 and 42)	measured by changes in faecal short chain fatty acids concentrations
Change in gut microbiome composition (from faecal samples) in response to dietary fibre	At baseline and end of each arm (study days 0, 14, 28 and 42)	measured by changes in bacterial 16S ribosomal ribonucleic acid gene sequencing; 16S rRNA
Change in glycaemic control in response to dietary fibre	At baseline and end of each arm (study days 0, 14, 28 and 42)	measured by acute and chronic changes in plasma glucose and insulin

Trial Locations

Locations (1)

Rowett Institute, University of Aberdeen; 🇬🇧 Aberdeen, United Kingdom