Sometimes I eat reasonably sized, nutrient-dense meals. Sometimes I see a pint of “Half Baked” in the freezer and think, nah, I’d rather have leafy greens. Sometimes I limit my caloric intake. But “sometimes” never, ever means “in the morning.” In the morning, I have no willpower: I hit the kitchen like a trash-happy raccoon and inhale double portions of, literally, whatever I find.
If I have a choice between traditional breakfast items and carton-shaped leftovers, I’ll most likely choose the former — and then the latter, too. My first meal of the day ranges from Greek yogurt to ice cream cake, enchiladas to overnight oats, three scrambled eggs to three bowls of cereal.
While I’m appropriately disturbed by my morning-time habits, I’ve also come to see them as a function of that hardwired biological trait known as chronotype. As a night owl, I may be predisposed to starting my day with the appetite of a lumberjack. At least, that’s my research-based theory and I’m sticking to it.
The science of self-control is the science of inaction. It’s about the process of not yielding to a temptation or impulse. This is not an area where we humans shine. And I particularly don’t shine at controlling myself around food before 9am.
All sorts of factors affect self-control: It’s easier to eat like a #fitspo model when your fridge is filled with cruciferous veggies and açaí elixirs. It’s also easier to resist the siren song of junk food when you’re happy and sober, rather than down in the dumps and 10 shots deep. But one 2017 paper proposed another under-recognized factor in the self-control equation: time of day.
In the paper, Brett Millar, a professor of health psychology at the City University of New York, argues that our capacity for self-control naturally fluctuates over the course of a day. And the timing of our self-control peaks and valleys depends somewhat on chronotype, i.e., where you fall on the scale of early bird to night owl.
Actually, the main point of the paper — which I covered here — is that failures of self-control are most likely to occur at night because that’s when self-control is most needed and least available. It’s most needed because it’s more acceptable, and thus easier, to consume and do bad things after dark. And it’s least available for two-ish reasons: People are 1) tired from being awake all day and 2) mentally drained from having to exercise self-control all day.
This second idea hinges on a once-popular theory known as ego depletion. Essentially, the theory says that self-control wears out over time like a muscle, making each feat of saying “no” cumulatively harder than the last. (Turning down a Snickers bar now makes it harder to pass up cake in an hour, and so on.)
But — but! — that’s not the whole story. The idea that nighttime = snack time, Millar concedes, may not fully apply to night owls. It’s not that chronotype affects the availability of temptations — opportunities to mainline Nutella at 9pm befall owls and early birds alike. The difference is that owls’ circadian clocks, and all the biological processes synced up to their circadian clocks, run on a delayed (read: wonderfully non-conformist) schedule. And that means owls tend to gain energy, rather than lose it, later in the day.
(The circadian system is actually one of two separate biological mechanisms that interact to affect levels of wakefulness. The other, called sleep-wake homeostasis, causes our drive for sleep to rise throughout the day. Here’s a more detailed explanation.)
The notion that night owls are wired to wake-and-binge is admittedly my own interpretation of Millar’s paper. But it’s an interpretation that jibes with other work on owls’ AM tendencies. Consider what we know about the “morning morality effect”: First proposed in 2013, the MME is another offshoot of ego depletion. It says that people act less morally as the day trudges on, i.e., they become more likely to cheat, lie, burgle, etc. But, a year after the MME came out, a different team of researchers discovered that the phenomenon only applied to morning people. Owls, their experiments showed, actually grew more ethical after sundown.
The MME findings are, in a sense, validating for owls, who’ve repeatedly been depicted in studies as self-destructive, vice-addled bad kids in contrast to their straight-laced up-and-at-em counterparts. But these depictions may not account for the way time-of-day affects mental and physical functioning.
If the bulk of experiments in chronobiology — a relatively young field concerned with sleep cycles and other biological rhythms — took place at night, perhaps we’d have different perceptions of owls and birds. And this is not merely my interpretation; it’s the rallying cry of big-deal chronobiologists including Till Roenneberg, the “father of chronobiology.” (Please don’t steal my “No Sleep TILL Brooklyn” t-shirt idea, thanks.)
Roenneberg believes that chronotype-based scheduling should dictate all sorts of things, such as when we work and when we get blood drawn. Night owls might be healthier if they weren’t constantly fighting their body clocks, Roenneberg has posited, because so many biological processes, including those related to metabolism and digestion, are tied to the circadian system.
I realize that my owl-ness doesn’t fully explain why I act feral in the morning. I mean, some studies say owls are more likely to skip breakfast than early birds, which boggles my morning-averse mind. And I can easily think of other explanations for my behavior, such as the fact that I exercise at night and really, really like coconut yogurt and … other stuff; human behavior is complicated. But I also know that I’m more drawn to treats in the morning than I am after I go for an afternoon run or work all day or tucker myself out at night with Netflix. And — owl’s honor — I swear that’s more than a chrono-coincidence.