Given the relatively high carbon footprint and sustainability of animal-based proteins, there is a growing interest in determining the nutritional quality non-animal-based protein sources. The overall objective of this investigation is to examine the impact of different animal and microbial-based protein sources to support whole body protein synthesis in adults. To do this, investigators will employ a 'breath test' method developed in our laboratory as well as urine sampling. The results of this study will allow us to better understand the impact of dietary protein quality for maintaining health and body protein mass in adults.

Inclusion Criteria:

• Healthy, male and female, recreationally-active participants.
• Healthy will be defined as screened by the PAR-Q+ (Appendix B) and The Physical Activity Readiness Questionnaire (Appendix C).
• Participants will be aged 18-45 years old.
• Participants are willing to abide by the compliance rules of this study.
• Self-reported regular menstrual cycle (25-35d) within the last 3 months (female participants).
• Use of monophasic combined oral contraceptives (COC) containing 21 active pills (e.g., Yaz, Marvelon, Cyclen, etc.; the brand of COC will be recorded) (female participants).

Exclusion Criteria:

• Inability to adhere to any of the compliance rules judged by principal investigator (e.g. dairy protein or yeast allergy).
• Self-reported regular tobacco use.
• Self-reported illicit drug use (e.g., growth hormone, testosterone, etc.).
• Individuals who have participated in studies within the past year involving any of the stable isotopes in the study.
• Use of multiphasic COCs due to the difficulty of controlling for hormonal fluctuations in such formulations (female participants).
• Use of COCs containing >21 active pills per cycle due to potential differences in their effect on metabolism (female participants).
• Use of other forms of hormonal contraception (e.g., progestin-only pill, hormonal IUD, intravaginal ring) (female participants).
• Not currently or previously (in the past 6 months) on a vegan diet