Effect of Meal Composition and Timing Modification on Glucose Metabolism, Body Temperature and Sleep

Inclusion Criteria: * Be 18 years of age or older; * Not be pregnant, if female; * Be generally healthy (with no apparent symptoms at the time of enrollment) * Patients with prediabetes or diet- controlled or type 2 diabetes or controlled with metformin, will also be allowed to participate. * Be willing to provide written informed consent for all study procedures. Exclusion Criteria: * major organ disease * pregnant/lactating * diabetes medications except for metformin * malabsorptive disorders like celiac sprue * heavy alcohol use * use of weight loss medications or specific diets * weight change \>2 Kg in the last month * history of bariatric surgery * Any medical condition that physicians believe would interfere with study participation or evaluation of results * Mental incapacity and/or cognitive impairment on the part of the patient that would preclude adequate understanding of, or cooperation with, the study protocol.