Appetitive Behavior
Conditions
Keywords
fibre, appetite control, gut microbiome, glycaemic control
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.
Interventions
OTHERPhase 1 - Control
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).
OTHERPhase 2 - High Fibre
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.
OTHERPhase 3 - Low Fibre
Low Fibre diet (30% Fat, 15% Protein, 55% Carbohydrate, 10g/day Fibre). Fed ad libitum.
Sponsors
University of Aberdeen
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
BASIC_SCIENCE
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
Yes
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)
Exclusion criteria
Medication
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| 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
| Measure | Time frame | Description |
|---|---|---|
| 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 |
Other
| Measure | Time frame | Description |
|---|---|---|
| Change in blood pressure in response to dietary fibre | At baseline and end of each arm (study days 0, 14, 28 and 42) | measured as mmHg on each test day |
| Change in waist and hip circumferences in response to dietary fibre | At baseline and end of each arm (study days 0, 14, 28 and 42) | measured as in cm with a tape measure on each test day |
| Change in waist to hip ratio in response to dietary fibre | At baseline and end of each arm (study days 0, 14, 28 and 42) | waist and hip measures will be combined to report waist to hip ratio |
| Change in Body Mass Index (BMI) in response to dietary fibre | At baseline and end of each arm (study days 0, 14, 28 and 42) | weight and height measures will be combined to report BMI in kg/m\^2 |
| Change in blood metabolites 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 short chain fatty acids (SCFA) |
| Change in appetite in response to dietary fibre | every day of study (42days) | measured daily, at end of day, using visual analogue scale questionnaires |
| Change in free-living glycaemic control in response to dietary fibre | every day of study (42days) | measured using continuous glucose monitoring (CGM) |
| Change in food intake | at screening (7days) and every day of study (42days) | measured using weighed intake records |
| Change in gastrointestinal symptoms in response to dietary fibre | every day of study (42days) | measured daily, at end of day, using questionnaires |
| Change in lipid profile in response to dietary fibre | At baseline and end of each arm (study days 0, 14, 28 and 42) | measured by change in fasting plasma lipid profile (cholesterol, HDL-cholesterol, LDL-cholesterol, triglycerides and non-esterified fatty acids (NEFA) |
| Change in diet markers in response to dietary fibre | At baseline and end of each arm (study days 0, 14, 28 and 42) | measured by change in urinary metabolites |
| Height | At screening visit only | measured in metres |
| Change in body weight in response to dietary fibre | At baseline and end of each arm (study days 0, 14, 28 and 42) | measured as weight in kilograms |
Countries
United Kingdom
Outcome results
None listed