High FODMAP Diet With Metformin in preDM

This is a prospective, double blinded, randomised cross over feeding trial examine high or low FODMAP diet in combination with metformin on postprandial glucose responses and gastrointestinal tolerability and gut microbiota profiles.The trial will compare high or low FODMAP diet, each of 10 days duration in combination with 5 days metformin, separated by a washout period of at least 2 weeks.

Inclusion Criteria:Age 18-70 yearsBody mass index 18 to 40 kg/m 2Prediabetes defined as impaired fasting PG 5.6-6.9 mmol/l and/or impaired glucose tolerance with 2-hour PG 7.8-11.1 mmol/l on 75g oral glucose tolerance test (OGTT) and/or HbA1c 5.7-6.4% at screeningExclusion Criteria:Currently pregnant, lactating, as demonstrated by a positive pregnancy test at screening or planning pregnancyKnown current diabetesCurrent or previous use of glucose-lowering or weight loss drugs in 3 months prior to screeningConcurrent participation in other weight loss or lifestyle intervention programmesCurrent use or recent exposure to any medication that in the opinion of the investigator could have an influence on the patient's ability to participate in this study or on the performance of the test device.Recent intake of prebiotic/probiotic or antibiotic, immunosuppressants (within 8 weeks of randomisation)Extensive skin changes/diseases that preclude wearing the FGM on normal skin at the proposed application sites (e.g., extensive psoriasis, recent burns or severe sunburn, extensive eczema, extensive scarring, extensive tattoos, dermatitis herpetiformis).Known uncontrolled thyrotoxicosisKnown vitamin B deficiencyKnown irritable bowel syndrome or gastrointestinal disordersEstimated glomerular filtration rate (eGFR) <45 ml/min/1.73m2 at screeningCurrent use of steroidsHave a known allergy to medical-grade adhesivesKnown current or recent alcohol or drug abuseHypersensitivity to metforminAcute or chronic metabolic acidosis, including diabetic ketoacidosis, with or without coma within 3 months of randomisationCurrently participating in another investigational study protocol where the testing or results may interfere with study compliance, diagnostic results, or data collection.An identified protected vulnerable patient (including but not limited to those in detention, or a prisoner).Participants who are on a vegetarian or vegan diet as their habitual diet at screening.Participants with clinically significant food allergy to components of the study diet