The effects of different popular diets on the metabolic profile

• Research type

  Research Study

• Full title

  A comparative study of two popular weight-loss diets and their effect on the metabolic profiles of: i) Healthy overweight and obese individuals ii) Overweight and obese breast cancer follow-up patients

• IRAS ID

  172966

• Contact name

  Gary Frost

• Contact email

  g.frost@imperial.ac.uk

• Sponsor organisation

  Imperial College London

• Duration of Study in the UK

  3 years, 0 months, 1 days

• Research summary

  DESIGN
  The trial will have two separate randomized, parallel cohorts. Each cohort will follow the same design and is in turn split into 3 /arms with each arms allocated to a different weight-loss diet. However there are two distinct populations being recruited, (study 1 and study 2).
  Study 1: A cohort of overweight or obese healthy men and women with a BMI > 25 will be randomised into 3 groups and follow one of the diets below for a total of 12 weeks.
  Study 2: A cohort of overweight or obese patients who have had curative surgery within the last 5 years to remove breast cancer (follow-up patients) will be randomised into 3 groups and follow one of the diets below for a total of 12 weeks.

  Diets:
  1) The ‘high fat’ Ketogenic diet
  2) The 5:2 diet: 2 ‘fast’ days each week with a calorie restriction to 500 calories a day but the participant eating as they choose on other days.
  3) Control group: A healthy balanced calorie restricted diet.

  Metabolic profiling will be performed on stool, urine and blood samples collected at the beginning and end of the intervention as well as at monthly interval throughout. Long-term effects will be assessed with a final follow-up and sample collection at six months. Dietary records will also be taken, as will measurements such as weight, Body Mass Index (BMI), blood pressure and insulin sensitivity as part of the study.

  POPULATION
  Study 1: Healthy overweight/obese men and women aged between 18 and 65 years.
  Study 2: Overweight/obese women who are breast cancer follow-up patients (had curative surgery to remove breast cancer in the last five years).

  ELIGIBILITY
  Study 1: Healthy men and women with a body mass index of >25 and aged 18 - 65 years.
  Study2: Women with a body mass index off >25 and have had curative surgery for breast cancer within 5 years.

  TREATMENT
  For both study 1 and study 2, participants the Intervention groups will receive either the 5:2 diets or the ketogenic diet. Participants in the control group will receive a normal balanced diet that matches their energy expenditure (15% protein, 40% fat, and 45% carbohydrate).

  DURATION
  The study will last 12 weeks with participants (in both study 1 and 2) being reviewed every 4 weeks and receiving telephone communication every 2 weeks. There will be a final, long-term follow up appointment at six months.

  OUTCOME MEASURES
  The primary outcome measure and end point of both studies is the effect of each diet on the metabolic profile. For study 2 in addition we will look at specific markers linked with increased cancer recurrence risk.

  These effects will be assessed through analysis of urine, stool and serum samples taken at regular intervals using a combination of untargeted and targeted spectroscopic assays. This includes global profiling via NMR spectroscopy and ultra-performance liquid-chromatography (UPLC)-MS; GC-MS profiling of short chain fatty acids (SCFAs) and targeted UPLC-MS screening of lipid, bile acid, eicosanoid and amino acid profiles.
  In addition for study 2 we are looking for any changes to metabolic risk factors for breast cancer or metabolites associated with cancer recurrence.

  Secondary outcome measures for both studies are as follows:
  • Weight loss
  • Insulin sensitivity
  • Alterations in gut microbiome composition

• REC name

  London - City & East Research Ethics Committee

• REC reference

  17/LO/1991

• Date of REC Opinion

  22 Nov 2017

• REC opinion

  Favourable Opinion