So, your training is going well, you feel motivated, powerful and positive. You are eating clean, fuelling your workouts without any cravings for junk food and you are feeling pretty good about your body. And then you wake up one morning and all you want to do is curl up under the duvet and eat your bodyweight in carbs. The outfits you usually love suddenly look just awful and everything seems to make you cry. You just don’t understand what’s happened and then, around a week later later the penny drops, as your period starts.

Sound familiar?

Everyone reacts differently around the time of their period and the changes in the hormones in our bodies may have a miscellany of effects, but the general sluggishness, desire to eat and emotional mood swings associated with the second half of the menstrual cycle seem to be quite common.

I was reading a little bit about these effects this week and about some tips for cyclical exercising and eating and wanted to share them with you here.

Firstly, why the sudden desire to eat so much?

In an article written for The American Dietetic Association, Jane Kirby noted that when we ovulate the body actually does require an extra boost in calories. Referencing a study from the University of British Columbia, she observed that women tend to eat differently during the second half of their cycles if they have ovulated that month, increasing their caloric intake by between 260 and 500 calories a day. Meanwhile, those women who did not ovulate, including those on birth control pills, found that their caloric intake remained relatively constant.

The researchers found that binge eating was common in the pre-menstrual, or luteal phase, when there was an increase progesterone production. While oestrogen, which was highest just before ovulation in the follicular phase, served to counter the cravings and act as an appetite suppressant.

Interestingly, this process of eating more during the pre-menstrual phase and appetite suppression during the follicular phase was also found to occur in non-human studies, suggesting that biological (not just cultural) factors contribute to female eating behaviour during the time of their period.

While you may be burning more energy during this phase of your cycle, it is important to note that your body is only burning between 100 and 300 additional calories – not the 500 you may want to guzzle in comforting treats.

However, taking a cyclical approach to your diet may help assuage the cravings and guilt associated with overeating. Accepting that you may need to take in an extra 150 calorie snack each day for the week before your period is a good start.

To avoid bloating and water retention, choose non-salty snacks. Increase foods rich in vitamin B6 by adding more beans, nuts, legumes, and fortified bread and cereals to your diet. Also aim to increase your zinc levels from nuts and whole grains and magnesium, found in legumes, nuts, whole grains, and vegetables for some guilt-free satiety.

Why does every outfit look wrong?

In her research at Michigan State University, Dr Kelly Klump discovered that the hormonal shift that causes changes in appetite during the menstrual cycle, also impacts on our body image.

In a recent issue of the ‘International Journal of Eating Disorders’ she and her associates examined changes across the menstrual cycle in two independent samples of women and found a direct effect of sex hormones on both appetite and body image. The researchers found that both binge eating and body dissatisfaction peaked during the pre-menstrual phase, when there was increased progesterone production.

Klump suggests that as progesterone leads to overeating, this in turn triggers body dissatisfaction. In addition, progesterone is thought to contributes to pre-menstrual anxiety, which can also make women feel more critical of their bodies.

And all of this is not helped by the bloated feeling which comes as increased estrogen levels cause your kidneys to redistribute water flow, and retain water.

In a vicious cycle, women feeling negatively towards their bodies may turn to emotional or comfort eating, resulting in a heightened sense of self-consciousness and self-loathing.

It is important to recognise when this cycle is beginning and to counter it by staving off hunger with healthy snacks and by keeping your mood positive with exercise.

Be reassured, these changes in emotions are totally normal and erratic mood swings don’t necessarily indicate abnormal hormone levels. In fact, the circulating levels of hormones in your body are likely to be totally normal but some researchers believe that the way we process them can vary, meaning symptoms can vary from woman to woman and from cycle to cycle.

Not in the mood to exercise?

All of the oestrogen and progesterone in your system in the pre-menstrual phase may also have a negative impact on your desire to exercise. During this time you tend to be less tolerant of heat because elevated progesterone levels delay your sweat response, the result of which is your body takes longer to expel excess warmth, not great if you are sweating away on a treadmill. You may also feel sluggish, since your metabolism shifts to use fat, rather than carbohydrate, as its primary energy source, and fatty acids are slower to release energy.

However, while you may not feel like running as fast or lifting as heavy weights, your body is still capable of handing its usual workload. Hormonal fluctuations don’t impact endurance, so even when your hormones are at their peak, your performance doesn’t have to suffer.

That said, if you’re really particularly rotten, this is the time of the month to give yourself a break without feeling too bad about it. Go for an easy run instead of doing intervals and skip tricky yoga poses and opt for relaxing ones.

The good news is, that while you may be suffering from cravings and negative body image before your period, the hormonal changes once your period starts can give you a boost in pain tolerance and muscle recovery.

Your oestrogen and progesterone level drop, and while this is only a subtle hormonal shift, Stacy Sims, Ph.D., an exercise physiologist at Stanford University and a leading researcher on the impact of menstruation on athletic performance, believes it’s enough that it could make you feel more powerful during exercise.

Her research shows that during this low-hormone phase, women also recover faster. She suggests that this may be due to the fact that the body ‘isn’t preoccupied with preparing for a possible pregnancy. Your baseline is reset into a more relaxed mode, so these other systems operate optimally.’

So give yourself the flexibility to push hard when you’re feeling good and to back off when you’re not.

And remember, within five minutes of cardiovascular exercise, you tend to feel happier Once you get moving, your brain releases serotonin, dopamine and norepinephrine which make you feel good. So, even if you don’t feel like doing anything, just going for a walk can make you happier and it may just be enough to distract you from the unhealthy snack you were craving.