Let's talk about periods.

We know they can be tough, and can wreak havoc on you physically — but have you ever wondered why weird food cravings a part of the deal?

If you're not familiar with the ways of the world, every month a woman who isn't pregnant will release a dead egg in her menstrual flow. (If this process lasts longer than a week you should probably see a doctor). In the week before and during a period, some women experience cramps, bloating, mood swings, and even food cravings, the last of which is a popular topic on social media.

So what's actually happening in your body when you have a food craving on your period?

First we should establish that women really do eat more eat more right before their period. It's not just their imagination. A study from researchers at the National Institute of Nutrition and Food Technology in Tunisia and published in the Annals of Endocrinology found that women's caloric intake rose as their periods approached.

Sequoia Holmes

Researchers followed the eating habits of women between the ages of 18 to 45 and saw significant changes.

• Women ate an average of 1,688 calories in the time right before ovulation (when the egg leaves the fallopian tube). This is the time directly after your period.
• They ate 2,175 when ovulation started.
• They ate 2,164 calories after ovulation. This is the time right before the beginning of your next menstrual cycle.

The researchers noted that most of the extra calories came from carbohydrates.

A 1989 study at the Massachusetts Institute of Technology found that women significantly increased their caloric intake in the days before their period, and most of these calories also came from carbs.

Danielle DeCourcey

Judith J. Wurtman, a lead researcher of the MIT study wrote about the study and period cravings in Psychology Today in 2010.

"The normal weight volunteers consumed about 1100 calories more when they were premenstrual than they did at other times of the month," she wrote. "And to no one's surprise, the extra calories came from chocolate, potato chips, cookies and crackers."

So why do you want to eat carbs and sugar when you're on your period?

In 2014, Women's Health asked Amanda Bontempo, an ambulatory oncology dietitian at New York University's Langone Medical Center, about period cravings. She said that in the days before a period the stress hormone cortisol rises and and seratonin decreases, a hormone that affects mood and social behavior. This causes a craving for sweets and carbs that can slow cortisol production and boost serotonin.

How do you stop period cravings from ruining your diet?

In her Psychology Today piece, Wurtman wrote that pre-menstrual symptoms can ruin a diet

"Our volunteers had no problem returning to their healthy way of eating once the PMS passed and they easily lost the pound or two they may have gained from their premenstrual munching," she wrote. "But for dieters, PMS poses more than a temporary halt in their weight loss. Premenstrual syndrome may cause the dieter to abandon her diet."

Wurtman wrote that a diet with low-carbohydrate snacks throughout the day can help keep overwhelming cravings at bay.

"The effects of eating a low or fat-free carbohydrate snack on your mood and appetite should be felt within 45 minutes or even sooner," she wrote. "After eating the snack, relax, meditate, read a book or contemplate that when you reach menopause, all this will be over."

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