Diet OrderDiet Order Effects of Low Fat vs. Low Carb Diets on Body Fat Change

• INCLUSION CRITERIA:

In order to be eligible to participate in this study, an individual must meet all of the following criteria:

1. Stated willingness to comply with all study procedures and availability for the duration of the study
2. Adults aged 18-50 years
3. Weight stable (< +/- 5% over past 6 months) as determined by volunteer report
4. Body mass index (BMI) >= 25 kg/m\^2
5. Agreement to adhere to Lifestyle Considerations throughout the study duration

EXCLUSION CRITERIA:

1. Subjects with cardiac pacemakers or other implants that may be affected by or affect the DXA measurements
2. Inadequate access to equipment required for the study (e.g., too little refrigerator storage space or a microwave oven that is too small) as determined by discretion of PI and/or study team
3. Evidence of diseases or conditions that may influence appetite (e.g., cancer, diabetes, alterations of smell or taste post COVID-19), diseases or conditions that affect the immune system, or other conditions at the discretion of the PI and/or study team
4. Taking prescription medications or other drugs that may influence metabolism (including but not limited to diet/weight-loss medication, some psychiatric medications, or other medications at the discretion of the PI and/or study team)
5. People unlikely to adhere to a relatively consistent daily and weekly routine and avoid travel during their participation in the study. For example, people with occupations such as pilots, flight attendants, or frequently travel for work or pleasure.
6. People unlikely to abstain from off study food or supplements that may impact metabolism or appetite at the discretion of the study team
7. Positive pregnancy test or lactating as determined by volunteer report (women only)
8. Inability or unwillingness to use birth control between screening and completion of the study (women only)
9. Symptoms or signs of perimenopause or menopause by volunteer report (women only)
10. Regular vigorous exercise >150 min per week as determined by volunteer report
11. Alcohol consumption > 3 drinks per day as determined by volunteer report
12. Regular use of tobacco (smoking, chewing, or vaping), nicotine replacement therapy, or illicit drugs over past 6 months as determined by volunteer report. Subjects may also be excluded based on a urine drug test.
13. Psychological conditions as determined by DSM-5 Self-rated Level 1 Cross-cutting Symptom Measure 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
14. 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
15. Volunteers unwilling or unable to give informed consent
16. Non-English speakers due to unavailability of required questionnaires in other languages
17. Resting Energy Expenditure test result within 10% of the 2500 calorie requirement at rest