Working out around Christmastime sucks. Unless you live in Arizona, Florida or Hawaii, the weather is probably colder than a bucket of penguin shit, and even if you stay home instead of visiting family or in-laws, you’re out of your routine, feeling that sweet holiday laziness. Basically, it’s all the ingredients you need to make a giant no-exercise sandwich. Annoyingly, the holidays are also when people pile on the most calories, thanks to all the seasonal parties, boozy reunions and celebratory feasts.
Don’t despair, though. If you’ve got a taste for spiked eggnog but don’t want to rub elbows with all the New Year’s resolution converts at the gym come January, there’s apparently a super simple way to keep the pounds off over the holidays: Work out before breakfast.
The concept first caught our attention in The New York Times back in 2010, partly because it sounded so simple. The article leaned on a study from Belgium that same year: In it, scientists rounded up 28 healthy men and made them eat 30 percent more calories than they were used to — calories of which 50 percent came from fat. A third of them didn’t exercise at all; the rest exercised four times a week, running or cycling strenuously for an hour or more. Of the exercisers, half ate a huge breakfast before exercising and drank a sports drink while running or cycling. The other half had no breakfast at all, and only drank water while exercising.
You’ll never guess what happened next: The guys who didn’t do any exercise got fat, gaining an average of six pounds over six weeks (and more worryingly, developing insulin resistance, which can lead to diabetes). The guys who ate breakfast before exercising, meanwhile, gained about half as much weight as the ones who didn’t exercise at all — and were also developing a resistance to insulin. But the ones who didn’t eat breakfast? Even on that lousy diet, they gained almost no weight at all, burned fat more efficiently, and didn’t develop any insulin resistance.
The reasoning is simple (albeit not yet entirely understood). When you work out in a fasted state, your body has far fewer carbohydrates to burn, so it turns to burning fat as fuel. This, of course, means your body is storing less fat. But working out on an empty stomach also boosts your body’s production of a protein that helps your muscles absorb insulin. In plain speak, that means working out on an empty stomach keeps off the weight and the fat, and makes you healthier.
Still, this information all comes from a study that’s seven years old, so we reached out to the study’s lead author, Peter Hespel, to see if he believes it still holds water. While there haven’t been any similar studies since that he’s aware of (likely due to how elaborate it was), “The key message of our earlier paper — notably that fasted, low/moderate endurance training during a period of hypercaloric diet inhibits weight gain, is definitely true,” Hespel tells us.
There is a big “but” here, though: Hespel stresses that this only applies to endurance activities, so don’t even think about power lifting, for example, on an empty stomach. “We have to avoid extrapolating the data to other training modes (resistance training, high-intensity endurance training, CrossFit), or to individuals on a ‘normal,’ well-balanced diet,” Hespel says. “I would never recommend individuals seeking an increase in muscle mass to do resistance training in the fasted state, because an adequate anabolic response requires ample availability of circulating amino acids.”
But what about the really important part? Can an endurance workout on an empty stomach help you keep the weight off through the holidays? “I would definitely say yes,” confirms Hespel.
So there you are: Go ahead and pig out this holiday season, as long as you start your day with a long run. Of course, during the holidays, getting up to do that might be the hardest part of all.