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Why Your Diet Is Giving You PMS

It's not all in your head.

The theories as to why women undergo emotional upheavals a few days before the end of their menstrual cycle range from the arcane to the absurd. It may not be the curse of an evil witch but water on the brain, an abnormal uterus, too much salt, too little vitamin B6, too little calcium, too much caffeine, too much sugar, too little fiber, and/or too little progesterone are some of the myths of yore. And so, it makes sense that the cause of these changes that come and go each month seems so mysterious.

Remedies for PMS no longer suggest eating the skin of a toad caught under a full moon or having a hysterectomy (as was suggested early in the 20th century). Both therapies have been proven ineffective. But a survey of women’s health websites produces almost as many suggested treatments as symptoms of PMS itself, and many of these so-called therapies have about as much efficacy as the toad.

We do know a few things: changes in female hormones throughout the menstrual cycle are linked to PMS, but not causative. Not all women with identical changes in levels of estrogen and progesterone will have PMS. The brain is involved, of course. The neurotransmitter, serotonin, which oversees mood, energy, concentration, and appetite, seems to become less active at the time the premenstrual symptoms arise. Indeed, some women who have a form of PMS that is extremely severe (PMDD or premenstrual dysphoric disorder) are helped by antidepressants, the SSRIs that increase serotonin activity. And studies carried out at MIT, and several PMS clinics in other major universities several years ago showed that the consumption of a carbohydrate-based beverage that increased serotonin levels decreased a variety of PMS symptoms such as anger, depression, confusion, lack of attention, and cravings for carbohydrates.

Based on these clinical studies, the connection between the well-known cravings of premenstrual women for chocolate and other sweet carbohydrates now made sense. Eating carbohydrates is a natural form of self-medicating. The increase in serotonin levels might not remove all the premenstrual symptoms but at least would make them bearable. Nutritionists may cringe at the nutrient content of a premenstrual diet limited to the four food groups: chocolate, chocolate, chocolate, and chocolate. But for the woman grappling with her premenstrual mood swings, fatigue, and temporary memory loss, eating to take the edge off these symptoms takes precedence over eating foods with better nutrient content.

Sadly, women are still being told to ignore their sugar cravings. For decades, physicians have assumed that because a woman “could kill for chocolate” when she is premenstrual, it is the sugar in the chocolate that is giving her homicidal tendencies. Years ago, when we first tested this association, we worried that we might be exacerbating the suffering of premenstrual women by asking them to consume sweet carbohydrates so their moods before and after the food was eaten could be tested. Fortunately, our results confirmed what premenstrual women have known all along. Sugar, along with other carbohydrates, diminishes rather than worsens premenstrual symptoms. Yet this information seems to have escaped the notice of the PMS experts giving advice on various websites devoted to women’s health. Avoiding sugar is usually the first recommendation given to women who hoped to diminish their PMS.

Fortunately, starchy carbohydrates have the same positive effect on serotonin and PMS as sugar. Pasta, potatoes, rice, polenta, bread, cereals, pancakes, and other starchy carbohydrates will also exert their mellowing effect on premenstrual mood by increasing serotonin. They should be eaten with little or no fat to speed up digestion and little or no protein which prevents serotonin from being made.

But women are facing another challenge to the natural way of dealing with their PMS. They are being told to follow diets that avoid carbohydrates altogether. “Carbohydrates will cause early deaths, rot your brain (along with your teeth), spike your blood sugar, depress your insulin, clog your fat cells and give you the personality of a drug addict!“ are some of the preposterous allegations I’ve heard. What the proponents of such advice seem to overlook or ignore is the natural dependency of the brain on the consumption of carbohydrates so that serotonin can be made. What they also overlook, they probably being males, is that women’s brains have less serotonin naturally than the brains of men. So when carbohydrates are avoided, and serotonin levels drop, women are more likely to suffer the effects on their mood, sleep, fatigue, and cravings than men at any time. Couple this with the natural drop in serotonin activity during PMS, and the resulting perfect storm of mood upheavals.

Conceivably, if one wanted to wish disastrous mood changes on one’s worst female enemy, telling her to avoid carbohydrates would be an effective way of making her miserable. Otherwise, well-intentioned diet advice that restricts carbohydrates for women when they are premenstrual should be given at one’s own peril. A Paleo diet man may be able to maintain a good mood while eating only barbecued bison, but he’d best be out hunting if he denies a Paleo woman her chocolate.

More from Judith J. Wurtman Ph.D.
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