On Tracking the Participants’ Caloric Intake
The researchers used the “doubly labeled water” method and changes in energy stores to objectively track caloric intake. In this urine-based test, a person drinks water that has had the hydrogen and oxygen atoms. These atoms have less common, but naturally occurring, stable, and traceable isotopes.
The study’s senior author, Dale A. Schoeller, PhD, Professor Emeritus of Nutritional Sciences at UW–Madison, pioneered the use of this technique in humans.
“This is considered the gold standard for objectively measuring daily energy expenditure in a non-laboratory, real-world setting,” Schoeller said.
Furthermore, the intervention’s simplicity was by far the most fascinating part of the study.
“We simply coached each individual on good sleep hygiene, and discussed their own personal sleep environments, providing tailored advice on changes they could make to improve their sleep duration. Importantly, to blind participants to sleep intervention, recruitment materials did not mention sleep intervention, allowing us to capture true habitual sleep patterns at baseline,” Dr. Tasali said.
After just one counseling session, participants improved their sleep duration by more than an hour per night. Moreover, most participants reduced their calorie intake significantly, with some eating as few as 500 fewer calories per day.