Fact or fiction: blood glucose response to ultra-processed foods

Dietary interventions: single meal responses to 16 different foods and three glucose standards on 19 different mornings. Each of the foods vary in food type, processing, and formulation, but all contain 25g of available carbohydrate (sugars and starch). The three glucose drink interventions are all the same exposure and also provide 25g of available carbohydrate. The average of the three glucose exposures is used as a way to account for within-person variability in how they respond day-to-day. Foods and glucose drinks are tested inline with the ISO standard for postprandial blood glucose testing. Each intervention is started in the morning with a fasted participant who has 10 minutes to consume the food and three hours sitting in a chair while their capillary blood glucose is measured. Blood glucose measurements are taken from fingers at baseline, then at 15, 30, 45, 60, 90, 120, 150, and 180 minutes. This morning process is conducted under observation. Participants are free to pursue their interests of this three hours, but are required to remain largely sedentary in a chair. The foods being tested are 1) Oranges (225g) either as whole fruit (with and without added fibre, or orange juice (with and without added fibre. 2) Legumes (200g) (cooked plain or with olive oil) or freeze dried cooked legumes (plain or with olive oil). 3) Cow milk (450g, plain or with added protein) or yoghurt made from cow milk (plain or with added protein). 4) Cooked oats (100-170g) either intact (with or without sugar) or milled (with or without sugar). The amount of oats served per morning varies, as the added sugar counts towards the 25g available carbohydrate that determines serve size. Participants will be asked to eat all interventions of that food type (i.e. the oranges), before being asked if they wish to continue to test the next food type (i.e. oats).