Stable Isotopes- Adults With Obesity

Participants will ingest six hourly meals designed to provide 50% of the daily intake of 1.1 g·kgLBM. Additional energy (1.5x daily resting metabolic rate), carbohydrate (55%), and fat (35%) will be provided in beverages and protein-free cookies (for palatability). The first drink will contain priming doses of NaH13CO2 (0.176 mg·kg-1), \[13C\]phenylalanine (1.86 mg·kg-1), \[2H5\]phenylalanine (0.34 mg·kg-1) with all subsequent drinks containing 1.2 mg·kg-1 \[13C\]phenylalanine and 0.51 mg·kg-1 \[2H5\]phenylalanine.

Participants will consume a 75g glucose drink dissolved in 250 ml of water enriched with \[6,6\_2H2\]glucose and \[13C6\]glucose.