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.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
BASIC_SCIENCE
Masking
NONE
Enrollment
7
Control diet (30% Fat, 15% Protein, 55% Carbohydrate, Fibre rising from 10 to 16g/d). Fed to energy balance (1.5 x Resting Metabolic Rate, RMR).
High Fibre diet (30% Fat, 15% Protein, 55% Carbohydrate, 30g/day Fibre). Fed ad libitum, contains 20g/day pectin (split over breakfast, lunch and dinner) in drinks/yoghurts which will be compulsory to consume and 10g/day fibre coming from the diet provided.
Low Fibre diet (30% Fat, 15% Protein, 55% Carbohydrate, 10g/day Fibre). Fed ad libitum.
Rowett Institute, University of Aberdeen
Aberdeen, United Kingdom
Change in gut hormones to assess appetite response to dietary fibre
measured by acute and chronic changes in plasma ghrelin and peptide YY (PYY)
Time frame: At baseline and end of each arm (study days 0, 14, 28 and 42)
Change in subjective hunger to assess appetite response to dietary fibre
measured by acute and chronic changes in appetite using visual analogue scale questionnaires
Time frame: At baseline and end of each arm (study days 0, 14, 28 and 42)
Change in gut metabolites (from faecal samples) in response to dietary fibre
measured by changes in faecal short chain fatty acids concentrations
Time frame: At baseline and end of each arm (study days 0, 14, 28 and 42)
Change in gut microbiome composition (from faecal samples) in response to dietary fibre
measured by changes in bacterial 16S ribosomal ribonucleic acid gene sequencing; 16S rRNA
Time frame: At baseline and end of each arm (study days 0, 14, 28 and 42)
Change in glycaemic control in response to dietary fibre
measured by acute and chronic changes in plasma glucose and insulin
Time frame: At baseline and end of each arm (study days 0, 14, 28 and 42)
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