Drink up? study tests if water intake changes how your body burns fuel

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Subject is male or female * If female, subject is not pregnant * If female, subject has stopped taking birth control medication or removed long-acting reversible contraceptive \>6 months at start of the study * If female, subject has normal menstrual cycle (25-35 days) * If female, subject is currently tracking their menstrual cycle using a smartphone application * If female subject is taking iron supplement, they are willing to continue supplementation during entire study * If female, subject has a smartphone compatible for application to track menstrual cycle * Subject is 18-35 years of age, inclusive * Subject body mass index (BMI) is between 18.5-25 kg/m2 * Subject is at least recreationally active (engaged in moderate-intensity, intermittent, or steady-state exercise at least 3 days per week for at least 60 min at a time) * Subject is accustomed to cycling for at least 60 min (Part 1 only) * Subject does not smoke (or has quit for at least 6 months) * Subject is not taking medication that may interfere with the study (e.g., diuretics, laxatives, or weight loss drugs) * Subject has no health conditions that would interfere with the study * As indicated on the general health questionnaire (GHQ) * e.g. cardiovascular, renal, or metabolic diseases * Subject is willing to refrain from having MRI scan during study protocol (Part 2 only) * Subject is not actively involved in weight loss intervention (dieting and/or anti-obesity medications) * Subject is not allergic to adhesives (e.g., medical tape) * Subject is not allergic to citrus-raspberry flavor (Part 2 only) * Subject is willing to avoid alcohol consumption 24 hours prior to visit(s) * Subject is willing to fast overnight (\~8-12 hours) * Subject is willing to refrain from vigorous exercise for 24 hours (light physical activity only) * Subject is willing to be shaved at patch or electrode site, if necessary (Part 1 only) * Subject is willing to eat the exact same food prior to each visit to the laboratory * Subject is willing to replicate exact diet and physical activity 24 hours before Visits 2/4 and for the 3 days between Visits 3/5 (Part 2 only) * Able to speak, write, and read English * Provision of written consent to participate Exclusion Criteria: * Subject has participated in a clinical trial within the past 30 days * Subject has participated in any PepsiCo trial within past 3 months (with the exception of Part 1 participants) * Subject has a condition or is taking medication that the investigator believes would interfere with his/her ability to provide informed consent, comply with the study protocol, which might confound the interpretation of the study results, or put the person at undue risk * Subject is allergic to alcohol (alcohol prep pads are used for blood draws). * If female, subject is taking birth control medication or has long-acting reversible contraceptive * If female, subject is anemic * If male, subject is undergoing hormone therapy to alter testosterone levels (injections, transdermal patch, pill, etc.) * Subject is employed by, or has a parent, guardian, or other immediate family member employed by a company that manufactures any products that compete with any Gatorade product. If subject is unsure if a company would be considered a competitor to Gatorade, they will be asked to please let the study investigator know the name of the other company and the nature of their relationship to that company before they sign the informed consent.