Evaluating change in the colonic luminal environment with protein supplementation (EAT PROTEIN)

The intervention in this trial is protein supplementation. The intervention will be provided in the form of "ingredient sachets" which will be developed in a research/commercial level kitchen. The protein-based ingredient sachets will contain 30g of whey protein isolate and 20g of full cream milk powder. Participants will consume three ingredient sachets per day, during the intervention weeks, incorporating them into their habitual diet by making into drinks or adding to food items. All participants will have two weeks of protein supplementation, followed by four weeks of habitual diet, followed by two weeks of protein supplementation (counterbalanced design). Participants will receive education from a research dietitian at a face-to-face 1-hour appointment at the hospital clinic. The education will be tailored to their individual diet to assist with adherence and to ensure maintenance of isocaloric intake to their habitual diet. Participants will also receive a supplementation guide developed for the purpose of this study, providing ideas of how to prepare the ingredient sachets. Adherence will be assessed via self-reported questionnaire indicating number of non-adherent days and confirmed by participants returning their supplement packaging.