The purpose of this parallel design study is to assess the relative effects of two 12-week healthy eating dietary interventions: general healthy eating (Diet A) and general healthy eating combined with advice to increase fibre intake (Diet B) to at least 25g/day (with a large proportion of the fibre intake derived from cereal or wheat bran), in overweight low-fibre consuming premenopausal female adults on body weight change (kg). It is hypothesized that adding fibre to a healthy eating diet (Diet B) would lead to greater weight loss and/or weight loss maintenance than following a healthy eating diet alone (Diet A).
In this randomised, single blind, parallel design study participants were randomly assigned to one of two 12-week healthy eating dietary interventions: Diet A: general healthy eating OR Diet B: general healthy eating combined with advice to increase fibre intake to at least 25g/day (with a large proportion of the fibre intake derived from cereal or wheat bran.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
TRIPLE
Enrollment
80
Participants were randomly assigned to one of two parallel arms: Diet A:healthy eating without extra advice to increase fibre intake or Diet B: healthy eating with extra advice to increase fibre intake to a minimum of 25g/d. Healthy eating advice was based on the British Heart Foundation booklet: "Food Should Be Fun And Healthy". Participants following Diet A were encouraged to eat breakfast cereals and were provided with complementary cereals and snacks low in fibre. Participants following Diet B were encouraged to eat high fibre breakfast cereals and to incorporate wheat bran fibre in other meals. Complementary high fibre cereals and snacks were provided.
Institute of Psychological Sciences
Leeds, United Kingdom
body weight change (kg) during the 12 week intervention
Body weight will be measured three times using ADP (BodPod, Concord, CA, USA); once during the inclusion phase (week -1), at the end of the intervention (week 12) and at follow up (one year later). Body weight will also be measured six times using bioimpedance (Tanita, Illinois, USA); once during the inclusion phase (week -1) and then again during weeks 4, 8, 12 of the intervention phase and at follow up (one month later and one year later)
Time frame: at screening and every 4 weeks at each subsequent visit, the last week of the intervention (week 12), at one month and one year after the intervention has finished
Food Intake
A 7-day food intake diary (self-reported food intake using household measures) will be completed during the first week of the inclusion phase to allow an assessment of habitual daily energy, macronutrient and fibre intake. Three-day food intake diaries (self-reported food intake using household measures on 2 weekdays and 1 weekend day) will be completed during study weeks 1, 5, 9, 12 and at one year follow up
Time frame: 7 day food diary the week before starting the intervention; 3 day food diaries at baseline (first week of the intervention), then baseline +4 weeks, baseline +8 weeks, baseline +12 weeks, baseline +12 months
Glycaemic regulation
This will be assessed using continuous glucose monitoring (CGMS) in a subsample of participants N=24, with N=12 from each treatment arm. Fasting measures of insulin and glucose will be obtained to assess Homeostasis Model Assessment (HOMA) and diabetes risk before and at the end of the intervention
Time frame: at baseline (first week of the intervention over a period of 3 days) and at baseline +12 weeks (last week of the intervention over a period of 3 days)
Biochemical measures
Fasting blood samples will be collected during the first week of the intervention and in the last week of the intervention (week 12) on the morning of a test meal challenge day. These fasting samples will be assayed for glucose, insulin, cholesterol, triglycerides and also leptin. These blood samples will be collected at the phlebotomy outpatient clinic at the Leeds General Infirmary. Further blood samples, which will be assayed for appetite hormones (Ghrelin, GLP-1, PYY and CCK), will be taken pre and post lunch on the test meal challenge days via a cannula fitted by a research nurse.
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Time frame: at baseline (first week of the intervention) and then at baseline +12 weeks (last week of the intervention)
Subjective symptoms, wellbeing and Mood
Each day women will complete a symptom checklist which will ask them to rate a range of symptoms on a five point Likert Scale from 0 (none) to 4 (extreme). The checklist will comprise items relating to women's general wellbeing (e.g. digestive sensations, mood and wellbeing). Women will note down whether they are menstruating. Participants on Diet B will record the amount of fibre they have consumed using a points-based system, as a measure of compliance. Each day all women will be asked to complete the Bristol Stool Form Scale (BSFQ; O'Donnell et al., 1990)
Time frame: Wellbeing Diary Booklets (WDBs) will be completed each day from screening till the last week of the intervention (week 12)
Sleep and body shape perception
Participants will be asked to complete an adapted version of the Leeds Sleep Evaluation Questionnaire (LSEQ; Parrott and Hindmarch, 1978) and Body Shape Questionnaire (BSQ-34; Cooper et al, 1987) during the visits at weeks -1, 4, 12 and at one month and at one year follow up
Time frame: at baseline (first week of the intervention), baseline +4 weeks, baseline +8 weeks, baseline +12 weeks, baseline +16 weeks and then at baseline +12 months
Eating behaviour
Eating behaviour will be assessed using the Dutch Eating Behaviour Questionnaire (DEBQ; van Strien et al., 1986) and the Three Factor Eating Questionnaire (TFEQ; Stunkard and Messick, 1985) at weeks 1, 4 , 8, 12 and at follow up (one month and one year later) to provide measures of dietary restraint and other psychological aspects of eating behaviour. At follow up (one year later) participants will also be asked to complete the Intuitive Eating Scale (IES; Tylka, 2006) in order to measure the levels of intuitive eating behaviour
Time frame: at baseline (first week of the intervention), baseline +4 weeks, baseline +8 weeks, baseline +12 weeks, baseline +16 weeks and then at baseline +12 months
Diet Satisfaction
The Diet Satisfaction questionnaire (D-SAT; Ello-Martin et al., 2004) to assess participants satisfaction with their current diet
Time frame: at baseline +12 months
Depression Anxiety and Stress
The Depression Anxiety Stress Scale (DAAS42; Lovibond and Lovibond,1995) will be used to assess depression anxiety and stress at one year follow up in order to assess symptoms of depression, anxiety and stress.
Time frame: at baseline +12 months
Life events
Participants will be asked to complete the Social Readjustment Rating Scale (SRRS) also known as Life Events Scale (LES; Holmes and Rahe, 1967) in order to assess stressful events that they may have experienced over the last 12 months
Time frame: at baseline +12 months
Dietary fibre intake
Participants will be asked to complete the Dietary Instrument for Nutrition Education (DINE; Roe et al., 1994) and the Leeds Women's Wellbeing Fibre Intake Assessment (LWW-FIA) to assess habitual fibre intake catergorically (DINE) and in grams/day (LWW-FIA)
Time frame: at recruitment visit, at baseline +12 weeks, at baseline +16 weeks and at baseline +12 months
body composition
Body composition will be measured four times using ADP (BodPod, Concord, CA, USA), once during the inclusion phase (week -1), once during the last week of the intervention (week 12) and at follow up (one month and one year later). Body composition will also be measured six times using bioimpedance (Tanita, Illinois, USA) at the inclusion phase (week -1), at weeks 4, 8, 12 of the intervention and at follow up (one month later and one year later).
Time frame: at baseline (first week of the intervention), baseline +4 weeks, baseline +8 weeks, baseline +12 weeks, baseline +16 weeks and then at baseline +12 months
Waist circumference
Waist circumference will be taken six times according to established methods (Van der Kooy and Seidell, 1993) during the inclusion phase (week -1), at weeks 4,8,12 of the intervention and at follow up (one month later and one year later).
Time frame: at baseline (first week of the intervention), baseline +4 weeks, baseline +8 weeks, baseline +12 weeks, baseline +16 weeks and then at baseline +12 months
Appetite ratings
100mm Visual Analogue Scale (VAS) ratings of subjective motivation to eat (hunger, fullness, desire to eat and prospective consumption) were completed before and 4 times after a fixed energy lunch meal during the first week of the intervention and then again at the end of the intervention
Time frame: Five times over a period of 2 hours during a test meal challenge day once at the beiginning of the intervention (baseline) and once at the end of the intervention (baseline +12 months)
Food preferences
The Food Preference Checklist (FPC; Blundell and Rogers, 1980) will be completed before and immediately after consumption of the fixed energy test meal
Time frame: Before and after consumption of a fixed energy test meal at baseline (first week of the intervention) and again before and after the second test meal at the last week of the intervention (baseline + 12 months)