A warning for morning zombies: if you need an alarm to wake up in the am, you may be at risk of weight gain.

In a study from Germany, 69% of people reported “social jet lag”, a situation in which your daily schedule is at least an hour off your internal body clock. Socially jet-lagged folks were three times as likely to be overweight. Sleep times that don’t regularly sync up with your body clock may alter metabolism, the researchers say.

Our advice: go to bed an hour early tonight and see if you wake up before the alarm sounds.