The study was stopped due to insufficient dietary differences, loss of support for the sleep device after acquisition, and high variability in temperature data, all these prevented meaningful evaluation of study aims.

The purpose of our study is to understand the impact of different meal timing alterations on blood sugars, metabolism, microbiome and sleep physiology in people with prediabetes and diabetes; and to study the temperature/heart rate response to different meals in different people.

Pilot data points to an effect of the time between waking up and first meal is important in blood glucose management through the rest of the day. The investigators are interested in understanding the effect of caloric distribution through the day, specifically consuming more later in the day versus earlier in the day. The investigators want to test the hypothesis that consolidating the meals during a shorter span in the day (time restricted eating) can ameliorate blood sugars and sleep parameters in the studied population. The researchers would also like to compare dynamic range of meal-induced sympathetic responses (e.g. temperature and heart rate changes) between different metabolic health conditions (e.g. insulin sensitive vs insulin resistant vs diabetes) while controlling for dietary intake. Previous research studies suggest that people with different metabolic health conditions would have different meal-induced sympathetic responses. Based on this, the primary goal of the study is to characterize metabolic health based on non-invasive wearable sensor data that measure these responses.

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.