Even without a menstrual tracker, many people can tell when they’re a couple days away from getting their period. That flash of irrational anger when Starbucks is out of almond milk starts to make sense when it’s coupled with a desire for cookie dough ice-cream and a wave of fatigue. IMO, tampons should just come with a dark chocolate bar.

While it may seem like the universe is rigged against you, there’s actually a purpose behind the types of foods people crave before and during their periods. In her new book The Better Period Food Solution, registered dietitian and You Versus Food host Tracy Lockwood Beckerman, RD, reveals not only the reason for craving carbs and fats instead of healthier foods, but also how menstruation affects hunger levels in general. Seriously, where was this intel in seventh grade health class?

How your cycle affects how hungry you are

There’s one specific time of the month where you’re more likely to be hungrier than normal. No, it’s not during your period—it’s in the first few days after ovulation (roughly halfway through your cycle if you have a 28-day cycle.) According to Beckerman, this period of your menstrual cycle is called the luteal phase, which is when your body’s main goal is to thicken and build up the uterine lining to prepare for a potential pregnancy. “If you don’t get pregnant, that uterine lining is ultimately what is going to be shed during your next period,” Beckerman says. “In assembling this so called ‘cushion’ in your uterus needed to support fertilization, the body requires more energy from nutrients in the luteal phase.” In other words, your body needs energy to build up the uterine lining, which is why it’s sending the body a signal to eat heartier than usual.

Beckerman says that another reason why it’s normal to feel hungrier at this part of the cycle is that your resting metabolic rate increases, meaning that you’re burning anywhere between 2 and 10 percent more calories than normal. “In the luteal phase, there is a drastic rise and fall of estrogen and progesterone which may be contributing to this increase in metabolism,” Beckerman says. “As we burn more calories, our tendency to be more hungry is only natural. But this phenomenon essentially cancels itself out at the end of the day because if we burn more calories and then we eat more calories, it starts us back at zero.”

For the average person, the luteal phase lasts between 12 and 14 days. Don’t expect to feel super hungry the entire time—that feeling is mostly concentrated in the first few days post-ovulation. But Beckerman says you can expect to feel ravenous again at the end of the luteal phase, which is when estrogen and progesterone levels drop. “Estrogen on its own is known to suppress appetite, and when that starts to crash down at the end of the luteal phase, right before PMS, our appetites can come back with a vengeance,” she says.

Why you crave unhealthy food before and during your period

Speaking of craving junk food, there’s a scientific reason for that, too. Simply put, carbs and fat make us (momentarily) happy. “The crashing of estrogen and progesterone cause our mood-boosting chemicals, like dopamine and serotonin, to plummet, making food an easy solution to help us turn that frown upside-down,” Beckerman explains.

Let’s face it: the days leading up to your period—and the first couple days you’re on it—aren’t fun. You have cramps, feel bloated, and are moody AF. A bowl of mac-and-cheese provides at least a temporary comfort and boosts serotonin. While that’s a totally valid approach every once in a while, Beckerman says no one will feel great in the long run if they rely on unhealthy foods to get them through a large part of the month, every month. Most traditional comfort foods are high in either refined sugar or carbs, which can cause blood sugar spikes and crashes that affect energy and mood levels; if they make up the bulk of one’s diet, that’s not going to be particularly helpful for maintaining a healthy, well-rounded diet.

Of course, that doesn’t mean that you have to deny your cravings. “Instead of avoiding carbs completely like it’s the plague, arm yourself with better-for-you carb choices like satisfying and warm grain bowls, refreshing grapefruit, or DIY energy balls,” Beckerman says. “Plus, eating colorful fruits and vegetables will not just put your in a better mood but will also help to quench cravings.” (And yes, even a square of dark chocolate will help.)

Check out the video below for food choices that will make you feel amazing before and during your period:

The fact that dopamine and serotonin levels drop during this part of the cycle doesn’t mean food is the only way to show yourself some comfort. Doing something you love—whether it’s watching your fave ’90s movie, signing up for your favorite yoga class, spending time by yourself reading a good book, or meeting up with friends are all ways to elevate your mood, too.