The goal of this placebo-controlled, partial crossover design study is to identify the impact of consuming whey protein before meals on free-living glucose control in older adults living with type 2 diabetes.

The primary specific objective is to determine the effect of a thrice daily whey protein pre-meal supplementation at two doses, on glucose excursions over a 7-day free-living period in adults aged 75-90 years of age, living with type 2 diabetes, compared with a non-protein placebo.

Participants will consume the whey protein and placebo for 7 days each, before each meal. All participants will consume the placebo and one of two doses of whey protein, in a randomised order.

Within the study, the researchers will look at the effect of supplemental whey protein at moderate and low doses in comparison to each other and a protein-free placebo on glycaemic control in older adults aged between 75-90 years of age, living with type 2 diabetes.

Glycaemic control (glucose excursions) will be monitored under free-living conditions over a 7-day period using continuous glucose monitors (CGMs). Participants will be randomised to consume one of the two whey protein doses as well as the protein-free placebo on a separate 7-day period. The order of consuming whey protein or the protein-free placebo will be randomised and counterbalanced. This study is under the evidence that in younger people living with type 2 diabetes, a moderate dose of whey protein improves glucose time in range and lessens extreme postprandial glucose excursions.

Participants will be free to consume their typical diet over this period, where the researchers will provide a diet diary for participants to enter in all foods and drinks they consume over this time period, as well as document the ingestion of the supplement before each main meal.

During an acute feeding period on the first ingestion of each supplement (start of each 7-day phase), the researchers will evaluate rates of gastric emptying, glucose and insulin concentrations and hormonal appetite markers through blood draws, as well as perceived appetite responses through visual analogue scales. This will be in a research kitchen where participants will consume the supplement and a controlled mixed meal afterwards to monitor excursions in appetite response and glycemia. The researchers will also investigate the impact of pre-meal protein feeding on renal markers following each 7-day phase via urine collection.

• Male or female
• 75-90 years old
• Type 2 Diabetes (confirmed with glycated haemoglobin (HbA1c) >6.5% in clinic or in SportExR)
• Stable body mass (body mass index (BMI) ≤40kg/m2)
• Generally healthy, assessed via a General Health Questionnaire (GHQ)
• Some residual beta-cell activity (confirmed with urine test on induction)
• Normal or moderately increased albuminuria (needs to be below 300mg/g)
• Normal, mildly or moderately decreased glomerular filtration rate (GFR) (needs to be above 45ml/min/1.732).
• Able and willing to attend SportExR a total of 5 times: 1 induction and 2 testing visits and 2 return check-up visits.

Exclusion Criteria:

• <75 years old and over 90 years of age
• Currently on fast-acting insulin therapy (i.e., Humalog)
• Confirmed uncontrolled diabetes (HbA1C >10% or 85mmol/mol).
• Currently on GLP-1 therapy
• Habitual smoker or vaper
• Veganism
• Lactose or dairy intolerance
• Coeliac or gluten intolerance
• History of gastrointestinal disease
• Experienced a hyperglycaemic or hypoglycaemic event requiring treatment in the past 12 months
• Recent Ischemic stroke (<3 months).
• Use of anticoagulants (e.g. warfarin, rivaroxaban)
• Considered unwilling or unable to comply with the study protocol requirements by the research team