ISRCTN - ISRCTN14330469: Testing the feasibility of a 6:1 intermittent diet breast cancer prevention programme to promote healthy eating and prevent weight gain in women at increased risk of breast cancer

Plain English Summary

Background and study aims
Weight gain in young women increases risk of breast cancer and other cancers and conditions. Weight gain occurs in young women attending breast cancer risk clinics and there is an unmet need for effective weight gain prevention interventions for these women. The study is testing whether a novel intermittent 6:1 intermittent diet is acceptable and can promote healthy eating and limit weight gain with minimal harms in women at increased risk of breast cancer. Findings in this study will inform whether further research with the 6:1 intermittent diet is warranted

Who can participate?
People who are born female and not undergone gender reassignment, aged 18-40 years who are at moderate or high risk of breast cancer and have a healthy BMI (20 - 25 kg/m²).

What does the study involve?
A special diet program aimed at preventing breast cancer. This program lasts for 4 months. We're inviting women from a clinic that focuses on family history and cancer genetics at Manchester University Foundation Trust, as well as those who are at high risk of breast cancer based on a study called BCAN–RAY.

The diet part of the program is called a 6:1 intermittent diet. Basically, for every week, there's one day where you eat fewer calories than usual, and the other six days you eat normally. We're also asking participants to do at least 150 minutes of moderate exercise every week, plus some strength training exercises.

To help you stick to the program, we'll provide support from dietitians through phone calls, video calls, and emails. You'll also have access to group sessions with other participants led by dietitians, and there's a private Facebook group just for this study where you can chat with others for support.

Before and after the program, you'll visit us in person to check your weight, body fat, and muscle. We'll also ask you to fill out some questionnaires about your eating habits, diet, sleep, and keep a food diary. You'll wear a small device on your wrist to track how active you are throughout the day.

During the program, we'll ask you to keep track of whether you did your low-calorie day each week, and if you experienced any side effects from the diet like headaches, hunger, or feeling tired. We'll also ask for your feedback on how acceptable the diet is through a questionnaire.

What are the potential benefits and risks of taking part?
The diet intervention could help improve diet, weight control and well being. However, none of these benefits can be guaranteed for the individual participants who take part. The information gained from this study on the safety, acceptability and potential efficacy of a 6:1 diet will help future people who seek advice from healthcare professionals on healthy diets to reduce weight gain and reduce cancer risk.
The health risks of taking part in the study are low as participants will be screened for their suitability prior to taking part. Some people may experience minor symptoms on low calorie days which may be associated with the diet such as fatigue, irritability (agitation), bad breath, constipation, dizziness, headache, indigestion. We are recording these as part of the study

Where is the study run from?
Manchester University Hospital Foundation NHS Trust, Manchester UK.

When is the study starting and how long is it expected to run?
November 2023 to July 2025

Who is funding the study?
The National Institute for Health and Care Research (NIHR) Manchester Biomedical Research Centre (BRC) Prevention and early detection theme (UK)

Who is the main contact?
Dr Michelle Harvie michelle.harvie@manchester.ac.uk

Study website

Contact information

Type

Public, Scientific, Principal Investigator

Contact name

Dr Michelle Harvie

ORCID ID

https://orcid.org/0000-0001-9761-3089

Contact details

First Floor Education and Research Centre
Manchester University Hospital Foundation NHS Trust
Wythenshawe
Manchester
M23 9LT
United Kingdom
+44 161 291 5815
Michelle.harvie@manchester.ac.uk

Additional identifiers

EudraCT/CTIS number

Nil known

IRAS number

ClinicalTrials.gov number

Nil known

Protocol/serial number

Sponsor reference G80390

Study information

Scientific title

The 6:1 intermittent diet breast cancer prevention programme study

Acronym

Study hypothesis

Weight gain in young women increases the risk of breast cancer and other cancers and conditions. Weight gain occurs in young women attending high-risk breast cancer prevention clinics and there is an unmet need for effective weight gain prevention interventions. This study is testing if a novel intermittent 6:1 diet is acceptable to women and can promote healthy eating and limit weight gain with minimal harm in women aged 18 - 40 years who are a healthy weight.

Ethics approval(s)

Not yet submitted

Study design

Single arm feasibility study

Primary study design

Interventional

Secondary study design

Non randomised study

Study setting(s)

Hospital

Study type

Prevention

Patient information sheet

To follow

Condition

Prevention of breast cancer in women at increased risk

Intervention

The 6:1 diet programme includes an intermittent 6:1 diet which involves one 1000 kcal day per week (to include ~70 g of protein and ~100g carbohydrate) and 6 days per week of healthy eating with a Mediterranean-type diet. It also encourages = or > 150 minutes of moderate-intensity exercise/ week. Participants will follow the programme for 4 months.

Intervention type

Behavioural

Primary outcome measure

1. Acceptability of the 6:1 intervention assessed through:
1.1. Uptake: The percentage of patients who are sent the patient information sheet who consent to participate and the percentage of eligible patients who consent to participate.
1.2. Retention to the study: the percentage of patients consented who complete the 4-month review
1.3. Adherence to the low-calorie days will be self-reported as the percentage completion of the potential low-calorie days between randomisation and the 4 month review.
1.4. Patient acceptability of the intervention will be assessed using a validated intervention evaluation questionnaire at the end of the study (Sekhon et al 2022).
2. Preliminary evaluation of any benefits of the diet
2.1. Changes in body weight and body composition (body fat and lean body mass assessed with bioelectrical impedance, waist and hip circumferences) between baseline and 4 months
2.2. Changes in diet quality (Mediterranean diet score) and alcohol intake (7- day recall) and energy and macronutrient intake from 7-day food record (Myfood24 app or 7-day paper food diary) between baseline and 2 and 4 months.
2.3. Changes in physical activity (International Physical Activity Questionnaire IPAQ short form) between baseline and 2 and 4 months and change in activity assessed with an Actigraph between baseline and 4 months i.e. time spent in sleep, sedentary, light, moderate and vigorous activity, total wear time and step count.
3. Preliminary evaluation of any possible harms
3.1. Changes in binge eating between baseline 2 and 4 months assessed with a binge eating questionnaire (Bruce et al J Am Diet Assoc 1996)
3.2. Change in sleep between baseline 2 and 4 months assessed using the Pittsburgh sleep quality index)
3.3. We will record the number of potentially diet related adverse events including fatigue, constipation, dizziness, headache, irritability (agitation), bad breath indigestion in the month before starting the diet and monthly throughout the intervention at each dietitian review call.
3.4. Mean menstrual cycle length for the month preceding and the 4 months of the programme will be assessed from self- reported diaries.

Secondary outcome measures

1. We will assess dietary intake and physical activity during low calorie and the other days of the week measured from 7 day food diaries at 2 and 4 months and actigraph measurements at 4 months
2. We will assess adherence to the 6:1 intermittent diet across the 4 weeks of the menstrual cycle measured using from self -report diet adherence and menstrual cycle diaries across each week of the 4 month intervention

Overall study start date

01/11/2023

Overall study end date

01/07/2025

Reason abandoned (if study stopped)

Eligibility

Participant inclusion criteria

1. Born female and not undergone gender reassignment aged 18-40 years.
2. Moderate or high risk of BC (>17% lifetime risk or >10 year risk of BC of >3% at 40)
3. BMI > or=20 and < or = 25 Kg/m²
4. Able to communicate (written and spoken) in English or other languages
5. Able to attend two face to face appointments at MFT at baseline and 4 months
6. Not pregnant or planning to become pregnant: Where appropriate potential participants will have a negative urine pregnancy test at screening and agreement to maintain contraception or abstinence for the trial.

Participant type(s)

Patient

Age group

Adult

Lower age limit

18 Years

Upper age limit

40 Years

Sex

Female

Target number of participants

30

Participant exclusion criteria

1. Previous breast cancer or bilateral preventative mastectomy
2. Currently trying to gain weight
3. Previously had weight loss surgery or taking weight loss medication
4. Have a medical condition that influences diet and weight, for example, diabetes, inflammatory bowel disease or cystic fibrosis.
5. Current diagnosis of a psychiatric disorder, for example bipolar psychotic disorder or current self-harm
6. Substance abuse or harmful alcohol use as indicated by a score of 16 or above on the Alcohol Use Disorders Identification Test (AUDIT)
7. Current or previous diagnosis of an eating disorder
8. Participants with severe binge eating assessed by a score of 27 or more on the Binge Eating Scale (BES)
9. Participants with severe depression assessed by a score of 15 or more on the Patient Health Questionnaire-9 (PHQ-9) questionnaire
10. Participants with severe anxiety assessed by a score of 15 or more on the General Anxiety Disorder (GAD-7) questionnaire.
11. Confirmed pregnant via a pregnancy test, planning pregnancy in the next 4 months, or currently breast feeding.

Recruitment start date

01/07/2024

Recruitment end date

01/12/2024

Locations

Countries of recruitment

England, United Kingdom

Study participating centre

Manchester University Hospital Foundation NHS Trust
Nightingale Centre, Wythenshawe Hospital
Wythenshawe
Manchester
M23 9LT
United Kingdom

Sponsor information

Organisation

Manchester University NHS Foundation Trust

Sponsor type

Hospital/treatment centre

Website

https://mft.nhs.uk/research/

ROR

https://ror.org/00he80998

Funders

Funder type