Effect of Dietary Habits on Metabolic Health

More than a third of U.S. adults are obese (BMI greater than 30), 8-12% of adults suffer from
type 2 diabetes, and up to 30% of adults have pre-diabetes. Recent research studies have
suggested that it is not just what we eat, but also when we eat that may put us at risk for
obesity and type 2 diabetes. Skipping breakfast and eating late at night have been associated
with an increased risk for obesity and type 2 diabetes (T2D), substantiated by recent animal
and human experimental studies showing that altered meal timing itself, without changes in
caloric intake, can influence weight regulation and impaired glucose tolerance. This research
will determine in prediabetic and non-diabetic participants whether delaying meal times
worsens glucose tolerance, leads to physiological changes favoring a positive energy balance,
and increases caloric intake. This research will provide mechanistic insights into the
metabolic consequences of changing meal timing and may help in evidence-based approaches to
improve dietary interventions in the fight against obesity and T2D.

Inclusion Criteria:

- BMI between 25 and 37.9 kgm-2

- Adults with regular sleep-wake timing

- Non-smokers

- Completion of medical and psychological screening tests

- Able to spend 14 consecutive days in the sleep laboratory

Exclusion Criteria:

- BMI < 25 or > 37.9 kgm-2

- History of neurological or psychiatric disorder

- History of sleep disorder or regular use of sleep-promoting medication

- Current prescription, herbal, or over-the-counter medication use

- Traveling across 2 or more time zones within past 3 months

- Donating blood within past 8 weeks

- Worked night or rotating shift work within past 3 years

- Hearing impairment

- Drug or alcohol dependency