Yes, you do burn more calories in the two weeks before your period, to the tune of about 10 percent of your resting metabolism. Unfortunately, according at least to calorieking.com, your appetite encourages you to eat about 500 extra calories per day. So unless you ignore about half your cravings (or indulge them all, halfway, whatever that means), nature is going to help you pork up for pregnancy whether there’s a bun in the oven or not.

While Googling to “authoritatively” answer the PMS metabolism question - doesn’t it seem like one of those wishful-thinking urban legends? - I discovered something I hadn’t heard: Not only is your metabolism up during PMS, it also relies more on fat burning than at other times of the month (although I’m only providing one link, I found several studies and articles on this topic, several in scientific papers). The effect isn’t significant, and requires workouts longer than I generally bother with lately (1 hour-plus), but for those like me who like to know what’s going on with their bodies in absurd detail, there you go!