Sweeteners under the microscope: do they mess with your blood sugar?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Age 45-79 years; * BMI of 20-35 kg/m2; * Having veins suitable for placement of a venflon catheter. Exclusion Criteria: * Diseases or prior surgeries affecting the stomach, liver, kidneys or intestines (allowed i.e. appendectomy); * Cardiovascular diseases (e.g. heart failure) or cancer (e.g. non-invasive skin cancer allowed); * Diagnosed with type 1 or type 2 diabetes; * Drug treated thyroid diseases (well substituted hypothyroidism is allowed for inclusion); * HbA1c level \>6.5% (\>48 mmol/mol), as measured during the screening visit; * Anaemia defined as Hb concentrations \<8.5 mmol/L for men and \<7.5 mmol/L for women via finger prick; * Regular use of/receiving medication interfering with research outcomes (as judged by research physician), such as use of glucose lowering drugs, insulin, or use of medication that impacts the gastro-intestinal system; * Use of antibiotics over the last 3 months before study start; * Donated blood within 2 months prior to the screening; * Food allergies, intolerances (including lactose/gluten intolerance) for products used in the study design and/or dietary restrictions interfering with the study (including special diets and eating disorders); * Followed a diet that can interfere with the study outcomes within 1 month prior to the screening (e.g. ketogenic, sugar free, carbohydrate free); * Not willing to eat all products in the study diet, including eggs and dairy. Vegetarian is possible; * Not willing to consume non-nutritive sweeteners; * Not willing to quit the use of supplements that can interfere with the study outcomes (e.g. pre- or probiotics). * Intention to change the intensity of exercise during the study period or planning to join a intensive sport event (e.g. marathon or triathlon); * Intention to lose or gain weight; * Working night shifts regularly; * Smoking regularly * Use of soft and/or hard drugs (cannabis included); * Abuse of alcohol (defined as \>14 glasses (women) or \>21 glasses (men) of alcoholic beverages per week); * Being pregnant or lactating or planning to become pregnant; * Inability to understand study information and/or communicate with staff; * Participation in another study that involves an intervention within two months prior to the intervention; * Working or doing a thesis/internship at the division of Human Nutrition \& Health, or the Food, Health \& Consumer Research group of Wageningen Food \& Biobased Research.