Using a Complex Carbohydrate Mixture to Steer Fermentation and Improve Metabolism in Adults With Overweight and Prediabetes (DISTAL)

Prior treatment

• Substance abuse (nicotine abuse (including e-cigarettes) defined as \>20 cigarettes per day; alcohol abuse defined as ≥8 drinks/week for females and ≥15 drinks/week for males(38); any drugs)
• Regular use of laxatives 3 months prior to the study or during study period

Other illness

• Diabetes mellitus (type 1 or 2)
• Cardiovascular disease (except hypertension (\<160/100mmHg is allowed), pulmonary disease, kidney disease/failure, liver disease/failure
• Gastrointestinal disease or a history of abdominal surgery (except appendectomy and cholecystectomy)
• Malignancy (except non-invasive skin cancer)
• Auto-immune disease
• Major mental disorders
• Following a vegan or vegetarian diet; presence of food allergies, intolerances or diet restrictions interfering with the study.

Lab values

• Diseases affecting glucose and/or lipid metabolism
• Use of medication that influences glucose or fat metabolism and inflammation, such as:
  • Use of statins (stable use ≥3 months prior to and during study is allowed)
  • Use of antidepressants (stable use ≥3 months prior to and during study is allowed)
  • Use of specific anticoagulants
  • Use of medication known to interfere with study outcomes
  • Use of β-blockers
  • Chronic corticosteroid treatment (\>7 consecutive days)

Age

• Ongoing (infectious) disease or any disease with a life expectancy ≤5 years

Other

• A change in weight ≥3kg over the last 3 months or plans to lose weight or follow a hypocaloric diet during the study period
• Pre/pro/antibiotic use in the last 3 months or during the study
• Change in physical activity or diet during study period
• Intensive physical activity (\>3h per week)
• Pregnancy

• Age 30-75 years
• Male/female
• BMI 28-40 kg/m2
• Impaired fasting glucose or glucose tolerance, determined using the following criteria (participant should meet at least one criteria):
• HbA1c 42-47 mmol/mol OR fasting glucose (\>10h fasted) 5.6-6.9 mmol/l OR Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) \>1.85