Nicotinamide Riboside for Obesity and Overweight

* INCLUSION CRITERIA: In order to be eligible to participate in this study, an individual must meet all of the following criteria: 1. Meet one of the following: 1. Adult males aged 18-65 years 2. Pre-menopausal adult females aged 18-50 years 3. Adult males aged 18-65 years with diagnosed maturity-onset diabetes of the young type 2 (MODY2) or pre-menopausal adult females aged 18-50 years with diagnosed MODY2 2. Weight stable (\< +/- 5 % body weight change over past 6 months) as determined by volunteer report 3. Body mass index (BMI) \>= 25 kg/m\^2 (of \>=18.5 kg/m\^2 for patients with MODY2) 4. Able to cycle at a moderate rate and intensity with a HR equal to or greater than 0.3x(220-age-HRrest)+HRrest but not exceeding 0.4x(220-age-HRrest)+HRrest with no signs of arrhythmia EXCLUSION CRITERIA: An individual who meets any of the following criteria will be excluded from participation in this study: 1. Taking prescription medications or other drugs or supplements that may influence energy metabolism or nutrient digestion or absorption (including, but not limited to, diet/weight-loss medication or other medications at the discretion of the PI and/or study team) 2. Indicators of liver disease; combination of both albumin \< 2.8 mg/mL and bilirubin \> 3 mg/mL 3. Individuals with significant medical comorbidities (e.g., non-MODY2 diabetes, NYHA Class \>II heart failure, or CKD Stage II or worse, or American Society of Anesthesiologists Physical Status Class 3 or above) 4. Individuals taking prescription medications to treat hypertension in participants without MODY2 5. Participating in a regular exercise program (\> 2h/week of vigorous activity) as determined by volunteer report 6. Positive pregnancy test (only for people who can get pregnant) 7. Hematocrit \< 40% (men only) 8. Hematocrit \<37% (women only) 9. Caffeine consumption \> 300 mg/day as determined by volunteer report 10. Alcohol consumption \> 3 drinks per day for men or \> 2 drinks per day for women as determined by volunteer report 11. Regular use of tobacco (smoking or chewing), e-cigarettes (a.k.a. vapes), nicotine patches, or illicit drugs over past 6 months as determined by volunteer report. Subjects may also be excluded based on a urine drug test. 12. Psychological conditions as determined by volunteer report such as (but not limited to) eating disorders, depression, bipolar disorders, that would be incompatible with safe and successful participation in this study, as determined by investigators 13. Volunteers with strict dietary concerns (e.g. vegetarian or kosher diet, food allergies) or a reported dislike of a significant fraction of the study foods 14. Unwilling or unable to comply with or perform all study procedures (e.g. cycling or activities of daily living), or unavailability for the duration of the study, as determined by participant or investigator discretion 15. Unwilling or unable to adhere to Lifestyle Considerations throughout study duration, as determined by participant or investigator discretion 16. Volunteers unwilling or unable to give informed consent 17. Participants with a measured Resting Energy Expenditure (REE) more than 30% above or below the predicted REE based on Mifflin St Jeor equation