Brunch Might Be Messing With Your Body Clock and Making You Put On Weight

Turns out there really isn’t such thing as a healthy brunch

If your brunch consists of a stack of chocolate chip pancakes, a side of eggs, bacon and a conservative three glasses of champagne (with the requisite splash of OJ), you’re probably already aware that it isn’t exactly the healthiest meal. But regardless of what you order, brunch can screw with your diet simply by being brunch — that is, your first meal of the day, a few hours later than you’d normally eat it. 

Even if you’re eating your regular weekday bowl of oatmeal, got your usual eight hours of sleep and never skip your daily jog, one study from the University of Barcelona suggests that people who eat brunch on the weekends have a higher body-mass index (BMI) than those who ate at the same time they would during the week. 

Researchers surveyed 1,100 students from Spain and Mexico about their usual mealtimes. About two-thirds ate their meals an hour later on the weekends than during the week, which isn’t a huge deal. But more than an hour difference correlated with being overweight, maxing out at an average 1.3 units higher BMI among those who ate brunch more than three hours later than their usual breakfast time. 

The thinking here is that, as with sleep, we run on a “body clock” with our meals. Our bodies become used to processing food at particular times, and when we eat outside of our usual meal periods, our bodies aren’t as prepared to transform that food into energy. As such, more of it goes unused, translating into more body fat. 

The science around body clocks is pretty solid, correlating with quantifiable measures like insulin levels, melatonin and glucose tolerance. Still, that doesn’t mean brunch is guaranteed to make you gain weight. As study author and professor of nutrition at the University of Barcelona, María Fernanda Zerón-Rugerio, explains, there are some other possible causes for this correlation between BMI and brunching. 

“Definitely, the most important mechanism would be the impact of the irregularity in meal timing, and its association with the body clock,” she says. “However, during weekends we tend to change our routine, which could mess with our eating habits. Thus, it’s also plausible that our weekend routine may be associated with a higher calorie consumption. However, more evidence needs to be warranted in this regard. While we evaluated diet quality, we didn’t focus on calorie consumption during weekends versus weekdays.”

But even if the correlation is simply the result of eating at the wrong time, there are ways of looking at it more optimistically. Zerón-Rugerio ultimately sees the study results as one possible method that people looking to maintain or lose weight can use to meet their goals. That is, eating breakfast at the same time every day might help people avoid being overweight. 

So rather than trying to make up for brunch through exercise or calorie restriction later in the day, Zerón-Rugerio suggests that keeping a regular eating schedule ought to be the priority. “Maintaining the regularity in sleep and meal timing is very important for the correct functioning of our biological clock, and thus, for health,” she says. “As such, the recommendation is to have meals regularly every day of the week, including breakfast. So it’s not a matter of ‘turning off’ the negative effects, but of adding one more recommendation to maintain health.” 

It’s also worth noting that not everyone sees BMI as an accurate measure of health or body type: Because it only considers weight and height and ignores muscle mass, bone density, gender and overall body composition, some medical professionals find the index misleading

In any case, if you’re worried about it, just eat breakfast at the same time every day. Wake up at 8 a.m. and eat a bowl of cereal after a night of partying, pass back out for four hours, then go to “brunch” for lunchtime. 

Okay, that’s probably not recommended, but let’s pretend our bodies are dumb enough to play along.