The Effects of Increasing Caloric Intake on Diet-Induced Thermogenesis and 24h Energy Expenditure

* INCLUSION CRITERIA: In order to be eligible to participate in this study, an individual must meet all of the following criteria: * Male or female, aged 18-60 years old * No episodes of intentional weight loss over previous 6 months EXCLUSION CRITERIA: An individual who meets any of the following criteria will be excluded from participation in this study: * Current use of tobacco products that exceed "Very Low Dependence" on the Fagerstrom Test for Nicotine Dependence Tool (score greater than 2) * Diabetes i. Fasting glucose \>= 126 mg/dl or hba1c \>= 6.5% or ii. history of type 1 or type 2 diabetes -Endocrine disorders, such as i. History of Cushing s disease, pituitary disorders, or hypo- and hyperthyroidism ii. TSH \<0.1 or \>= 10 uIU/mL * Pulmonary disorders i. History of chronic obstructive pulmonary disease or other lung disease that which would limit ability to follow the protocol (investigator judgment) * Cardiovascular diseases, i. Including history of coronary heart disease, heart failure, arrhythmias, and peripheral artery disease * Hypertension, i. History of diagnosis and current treatment by an outside clinician ii. or sitting blood pressure measurement, using an appropriate cuff, higher than 140/90 mmHg -Liver disease, i. including history of cirrhosis, active hepatitis B or C ii. AST or ALT \>=3 times upper limit of normal on screening labs * Renal disease i. Serum creatinine \>= 1.5 mg/dls * Abnormal kidney function (eGFR \<60 mL/min/1.73m\^2) * Central nervous system disease: i. including history of previous history of cerebrovascular accidents, dementia, and neurodegenerative disorders * Cancer: i. History requiring treatment in the past five years, except for non-melanoma skin cancers or cancers that have clearly been cured or in the opinion of the investigator carry an excellent prognosis (e.g., Stage 1 cervical cancer). * Infectious disease: i. History of active tuberculosis, HIV chronic coccidiomycosis or other chronic infections * Conditions not specifically mentioned above may serve as criteria for exclusion at the discretion of the investigators * Evidence of alcohol abuse as defined by \> =8-point score on the Alcohol consumption screening AUDIT questionnaire in adults * Current use of illegal drugs such as amphetamines, cocaine, opiates, or heroin; use of marijuana is permitted. * For Females: * i. Pregnancy or lactation by history and urine pregnancy test * ii. Peri- or post-menopause by self-report or irregular menstrual cycle. * Measured weight: greater than or equal to 450 lb. (maximum weight allowed on the DXA scanning tables by the manufacturer). * Inability to speak or read English by self-report. * Inability to provide informed consent * History of psychological conditions including (but not limited to) claustrophobia, clinical depression, bipolar disorders, or forms of mental incapacity that would be incompatible with safe and successful participation in this study * Current use of medications/dietary supplements/alternative therapies known to alter energy metabolism * Inability to consume provided diets due to dietary concerns that will not allow them to consume \>=95% of provided calories.