Protein is vital for the preservation of health and optimal adaptation to training. However, animal proteins come with economic and environmental issues. The study will investigate the effect of non-animal vs animal based habitual protein consumption on muscle protein metabolism and changes in muscle mass and function over a longer period of time.

Protein is vital for the preservation of health and optimal adaptation to training. However, animal proteins come with a number of economic and environmental issues. Accordingly, the investigators need to develop an evidence base for more sustainable dietary proteins to support human nutrition. Mycoprotein is a non-animal protein produced by the continuous fermentation of the fungus Fusarium Venenatum. Previously, in a mechanistic study, it was determined that a single bolus of mycoprotein effectively supports muscle building in both rested and exercised skeletal muscle, to a similar extent as what would be expected of animal proteins. This suggests that similar adaptation of muscle tissue during training could be achieved when protein is obtained from non-animal derived protein sources.

The study will investigate the effect of high non-animal vs animal based habitual protein consumption on muscle protein metabolism and changes in muscle mass and function over a longer period of time. Initially, the study will employ a stable isotope tracer to quantify muscle protein synthesis over a period of three days in healthy male and female volunteers. During this time participants will consume a controlled vegan diet or an animal based diet, with daily unilateral resistance exercise. The second phase of the study will employ a 10 week diet and resistance training intervention, with the majority of a participant's protein either coming from animal or non-animal sources. This will determine the ability of a largely non-animal derived diet to support augmentations in muscle size and strength.

Briefly, participants will undergo 6 muscle biopsies over the course of an 11 week period. Initial biopsies will quantify muscle protein synthesis. Subsequent biopsies will characterise the adaptive response to the effects of nutrition and exercise. MRI scans will be employed to determine changes in muscle volume, and DXA scans will measure changes in body composition.

Inclusion Criteria:

• Males and females 18 - 40 years of age.
• Body mass index between 18 and 30.
• Recreationally active.
• Resistance training experienced (have previous performed resistance exercise, and are familiar with the basic movements).

Exclusion Criteria:

• Any diagnosed metabolic impairment (e.g. type 1 or 2 Diabetes) (as this may affect normal protein metabolism).
• Any diagnosed cardiovascular disease or hypertension (to avoid any complications associated with heavy exercise).
• Elevated blood pressure at the time of screening. (An average systolic blood pressure reading of ≥140mmHg over two or more measurements and an average diastolic blood pressure of ≥90mmHg over two or more measurements.)
• Chronic use of any prescribed or over the counter pharmaceuticals (that may modulate muscle protein metabolism).
• A personal or family history of epilepsy, seizures or schizophrenia.
• Allergic to mycoprotein / Quorn, penicillin, or milk.
• Pregnancy.