Snack bars to see if hunger and gut health change with a high-fibre option

Is this trial a fit for you?

A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.

What this trial studies

This remote study tests whether a high-fibre snack bar affects daily hunger, gut microbiome, bowel habits, and digestive symptoms compared with a control snack bar. Over 5 weeks, participants replace their usual snacks with two bars daily and complete health assessments at the start and end, including a food diary, hunger surveys, body measurements, and a stool sample. The trial uses a parallel design with an intervention bar versus a control bar that reflects typical UK snacks. Results will help determine if snack composition, not just snacking frequency, influences hunger and gut-related outcomes.

Why it matters

Who can join: the full rules

Inclusion Criteria:

* Willing and able to follow the study protocol
* Willing and able to provide informed consent
* Regular consumption of snacks (≥2 per day)
* Fibre intake \<20 g/d
* Living in the UK

Exclusion Criteria:

* Have BMI of less than 18.5 kg/m² or more than 40 kg/m²
* Have an allergy or intolerance to ingredients in the intervention or control snack bars (including inulin) or cannot eat the food products safely and comfortably for any reason
* Have a personal medical history of inflammatory bowel disease, coeliac disease, Crohn's disease, irritable bowel syndrome, chronic constipation, or chronic diarrhoea
* Have started a new supplement in the past month, or are unwilling to maintain current supplement use throughout the study
* Previously purchased any ZOE products (including Daily30, ZOE gut health bar or ZOE app membership).
* Have taken any medication or product that may modify the measured study outcomes, in the past 3 months (including but not limited to: fibre supplements, antibiotics, non-topical steroids or other immunosuppressive medicines, probiotics or prebiotics, metformin, GLP-1 receptor agonists, lipid-lowering medications such as fibrates, statins, PCSK9 inhibitors, non-steroidal anti-inflammatory drugs)
* Have used opiate pain medication or a proton pump inhibitor for 8 or more consecutive days during the past 3 months
* Have experienced a heart attack, stroke or major surgery in the last 2 months
* Have received treatment for cancer in the last 3 months
* Are currently pregnant, breastfeeding or planning a pregnancy
* Are diagnosed with an eating disorder, type 1 diabetes mellitus or type 2 diabetes mellitus

Where it's running

• ZOE limited
  London, United Kingdom Recruiting

Study contacts

• Principal investigator: Berry E Sarah, Professor — King's College London
• Study coordinator: Study Co-ordinator
• Email: smarteats-trial@joinzoe.com
• Phone: +44 (0)330 818 8669

Similar studies

Other studies for the same condition or treatment. Recruiting studies are listed first.

• Does a high-fibre snack bar reduce post-meal hunger compared with a typical UK snack bar?

  This study tests whether a high-fibre plant-based snack bar can reduce hunger after eating, compared with a typical UK snack bar, in healthy adults.

  Recruiting Zoe Global Limited · London · NCT07776418

• How age affects germinal center responses after flu and rabies vaccines

  Researchers will test how the immune system responds to flu and rabies vaccines in younger adults (18–40) and older adults (65+).

  Recruiting Phase 4 Washington University School of Medicine · St Louis, Missouri · NCT07914673

• Magnetic field maps with NV sensors for non-invasive heart measurements

  This study tests whether diamond-based NV magnetometers can non-invasively detect and map the heart's magnetic field in healthy adults.

  Recruiting Robert Bosch GmbH · Renningen · NCT07908173

• Methylation analyses using home-based self-sampling in women with and without gynecological disease

  This study tests whether self-collected urine and vaginal samples can reveal DNA methylation markers that distinguish people with gynecological (pre-)cancers from cancer-free controls.

  Recruiting Universiteit Antwerpen · Edegem, Antwerp · NCT07902388

• Omega-3 status in healthy adults: comparing different fish-oil and algae-oil products

  This study tests whether various fish-oil and algae-oil products can raise the Omega-3 Index in healthy adults who don’t eat much fatty fish.

  Recruiting Nordic Naturals · London, Ontario · NCT07900425

• A safe, carefully dosed test of TBD11 in healthy adults

  This phase 1 study tests TBD11 in healthy adults to see if it is safe and tolerable and to understand how it behaves in the body, including how it interacts with other medicines.

  Recruiting Phase 1 Gates Medical Research Institute · Bloemfontein · NCT07883226

How to take part

1. Review the eligibility criteria above with your treating physician.
2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.