Circadian rhythms may help explain why breakfast skipping is associated with increased risk of weight gain, even among those who consume comparable amounts of calories in a day.
“The link between breakfast skipping and obesity had once been thought to be due to overcompensation of calories at subsequent meals due to excess hunger … but the research does not consistently show differences in total energy intake among breakfast-skippers,” Freuman said.
“Something else about skipping breakfast — aside from potentially eating more calories later in the day — must explain the greater risk of weight gain among breakfast skippers,” she said. A more likely answer: Eating more calories in the later part of the day is out of sync with metabolic circadian rhythms.
“We get less metabolically robust as we age,” she explained. “So even if you’ve gotten away with skipping breakfast and eating out of sync in your 20s or 30s, it may eventually catch up with you.”
Night shift workers can also benefit from eating in sync with their circadian rhythms. They may modify meal timing to sync up with metabolic circadian rhythms by eating breakfast at the end of their workday, at 7 or 8 a.m., and then eating their heaviest meal when they wake up, about 3 or 4 p.m.
Freuman discourages her night shift patients from eating during the night. “We don’t want them eating many calories, so we’ll have them sip on tea or have a Thermos of miso soup or, if need be, something small like an apple in order to minimize overnight calories.
“Your metabolism is working in a certain way, whether you are awake or asleep — so even if you are awake during most of the night, you still want to be eating most of your calories during daylight. Sleep has little to do with it,” Freuman said.