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There were issues with recruitment so study was stopped
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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.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Control - High Fibre - Low Fibre (CTRL - HF - LF) | Experimental |
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| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| Phase 1 - Control | Other | 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). |
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| Measure | Description | Time Frame |
|---|---|---|
| Change in gut hormones to assess appetite response to dietary fibre | measured by acute and chronic changes in plasma ghrelin and peptide YY (PYY) | 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 | At baseline and end of each arm (study days 0, 14, 28 and 42) |
| Measure | Description | Time Frame |
|---|---|---|
| Change in gut metabolites (from faecal samples) in response to dietary fibre | measured by changes in faecal short chain fatty acids concentrations | 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 |
| Measure | Description | Time Frame |
|---|---|---|
| Change in blood metabolites in response to dietary fibre | measured by acute and chronic changes in plasma short chain fatty acids (SCFA) | At baseline and end of each arm (study days 0, 14, 28 and 42) |
| Change in lipid profile in response to dietary fibre |
Inclusion Criteria:
Exclusion Criteria:
Medication exclusion criteria:
Medical exclusion criteria:
Other exclusion criteria:
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| Name | Affiliation | Role |
|---|---|---|
| Alexandra Johnstone, Prof | Rowett Institute, University of Aberdeen | Principal Investigator |
| Alexander Ross, Dr | Rowett Institute, University of Aberdeen | Principal Investigator |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| Rowett Institute, University of Aberdeen | Aberdeen | AB25 2ZD | United Kingdom |
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| ID | Term |
|---|---|
| D001070 | Appetitive Behavior |
| ID | Term |
|---|---|
| D001522 | Behavior, Animal |
| D001519 | Behavior |
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| Phase 2 - High Fibre | Other | 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. |
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| Phase 3 - Low Fibre | Other | Low Fibre diet (30% Fat, 15% Protein, 55% Carbohydrate, 10g/day Fibre). Fed ad libitum. |
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measured by changes in bacterial 16S ribosomal ribonucleic acid gene sequencing; 16S rRNA |
| 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 | 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)
| At baseline and end of each arm (study days 0, 14, 28 and 42) |
| Change in diet markers in response to dietary fibre | measured by change in urinary metabolites | At baseline and end of each arm (study days 0, 14, 28 and 42) |
| Height | measured in metres | At screening visit only |
| Change in body weight in response to dietary fibre | measured as weight in kilograms | At baseline and end of each arm (study days 0, 14, 28 and 42) |
| Change in blood pressure in response to dietary fibre | measured as mmHg on each test day | At baseline and end of each arm (study days 0, 14, 28 and 42) |
| Change in waist and hip circumferences in response to dietary fibre | measured as in cm with a tape measure on each test day | At baseline and end of each arm (study days 0, 14, 28 and 42) |
| Change in waist to hip ratio in response to dietary fibre | waist and hip measures will be combined to report waist to hip ratio | At baseline and end of each arm (study days 0, 14, 28 and 42) |
| Change in Body Mass Index (BMI) in response to dietary fibre | weight and height measures will be combined to report BMI in kg/m^2 | At baseline and end of each arm (study days 0, 14, 28 and 42) |
| Change in gastrointestinal symptoms in response to dietary fibre | measured daily, at end of day, using questionnaires | every day of study (42days) |
| Change in appetite in response to dietary fibre | measured daily, at end of day, using visual analogue scale questionnaires | every day of study (42days) |
| Change in free-living glycaemic control in response to dietary fibre | measured using continuous glucose monitoring (CGM) | every day of study (42days) |
| Change in food intake | measured using weighed intake records | at screening (7days) and every day of study (42days) |