Eating for Better Sleep & Foods that Improve Metabolic Health | Dr. Marie-Pierre St-Onge

Marie-Pierre St-Onge frames the conversation as bidirectional: sleep changes how much and what people eat, while food choices and meal timing can alter subsequent sleep. Population studies consistently associate short sleep with higher body mass index and later weight gain, including a 14-year nurses’ cohort in which women reporting five or six hours of sleep gained more weight than those reporting seven or eight hours. Those studies establish temporal and statistical relationships, but not causation, so her laboratory work tests the mechanism directly rather than treating correlation as proof.

In a crossover experiment, participants received either a nine-hour opportunity in bed or only four hours for five nights. During the initial controlled-feeding period they ate the same food, allowing the researchers to isolate sleep duration, and the final day measured self-selected intake. Short sleep increased ghrelin, a food-intake signal, in men, while women showed reduced GLP-1, a satiety-related signal. Participants ate roughly 300 additional calories after restricted sleep, and neuroimaging showed stronger responses in reward-related brain regions. The result is not a universal single pathway: the behavioral outcome was shared, but the observed physiological brake or accelerator differed by sex.

The sex-specific result was incidental rather than a prediction. Earlier studies, conducted mainly in men, had reported increased ghrelin and reduced leptin after sleep restriction. When St-Onge first analyzed men and women together, she found no overall ghrelin effect. Separating the sample revealed that the null result concealed a male-specific increase and no comparable increase in women. This exchange illustrates why a pooled average can hide meaningful subgroup differences, while also leaving open questions about why the pathways differ and whether the result generalizes beyond the study conditions.

The hosts connect these findings to the felt experience of sleep loss, including bodily discomfort and the possibility that eating becomes a way to seek reward or relief. St-Onge does not claim that one switch explains every response. The discussion instead points to interacting neural, endocrine and behavioral processes, and distinguishes the controlled evidence from hypotheses that still require testing.