StudyRepo

37 healthy students were asked to document their meals for 30 days, across the spring Daylight Savings Time change. Their mid-sleep times were measured, to find out if different diet composition would lead to different adaptation speeds to the new daylight environment. They analyzed diet composition and divided into 3 groups: low-fat (<35% kcal from fat), intermediate-fat (35-40% kcal from fat), and high-fat (>40% kcal from fat). Students eating a high-fat diet took significantly longer to adapt to the new DST environment, only adapting fully on the following Friday, whereas low-fat students were adapted after just 1 day.

Rodents were split into chow (low-fat) and "high-fat" (53% fat, 6% corn oil, 47% lard) groups. They were subjected to an artificial 6h "jet lag." Adaptation time was measured. The "high-fat" rodents took nearly 2x as long to advance phase, but were slightly faster at delaying phase. I.e. the "high-fat" PUFA diet turned them into night owls.