Period. Oh yes, we're going there!

This blog is going to help you understand your menstrual cycle better.

It will explain how hormones affect your mood and food consumption.

Periods should not be a taboo subject. They are a snapshot of your overall health.


A ‘normal period’ is considered a cycle length of 28 days, with a period lasting 3-5 days. In reality this varies between women.

If you have a regular cycle and start to experience irregularities, N\N suggest that you visit your GP.


The menstrual cycle prepares your body or fertilisation. Your hormones affect all aspects of your health and performance. You should not ignore them.

In the past exercise professionals, declared that a female’s menstrual cycle has no effect on her ability to exercise. You were advised to continue training and ‘push through’.

N\N however, disagree with this one rule fits all; instead promoting an individual approach.

Some women suffer negative physical and emotional changes over the course of their cycle.

Understanding how you respond is key to getting the most out of your exercise and nutrition. N\N show you how to work with your cycle changes rather than against them.


May start about 1-2 weeks after your first day of bleeding. It can include swings in mood, abdominal pain, breast tenderness, tiredness, anxiety and depression. The specific symptoms experienced will vary.

One in three women suffer discomforting symptoms in the days before their period and for one in 20, the symptoms seriously affect their lives.


Causes are unknown and poorly understood. Different theories include shifting hormone levels, changes in neurotransmitters, diet and nutritional deficiencies such as low magnesium.

Recently research has been turning its attention to a possible link between PMS and inflammation. Studies suggest that inflammation may play a role and recommend that avoiding behaviours associated with inflammation may be helpful.

These behaviours include smoking, a poor diet (high in trans-fats and low in plants), inactivity, and chronic stress. Dietary and lifestyle recommendations are N\N’s preferred method of treatment.


Research has been dedicated to finding treatments for PMS sufferers. Most agree that movement or exercise is as effective if not more so than drugs. One study concluded that aerobic exercise during PMS can reduce symptoms, resulting in better job and social performance.

Exercise can be an aid. However, the type and intensity must be monitored and adjusted to your emotional and physical state. N\N suggest Yoga as a gentle way of moving and assisting with mindfulness.


Altering your exercise programme to take advantage of the hormonal fluctuations occurring in your menstrual cycle. Changes in oestrogen and progesterone impact your mood, energy levels, appetite, fuel utilisation and sometimes performance.

Adjusting training intensity and calorie intake can make your menstrual cycle a little easier if needed.

This Menstrual Cycle Based Approach (MCBA) is how N\N further individualise and customise your exercised nutrition prescription to bring out the best in you.


During your period you are in a low hormone phase; both oestrogen and progesterone levels are low. At this time women are physiologically, ‘most like men’. Often you will perform well and feel particularly strong during training.

Any PMS type symptoms, including food cravings and feelings of being bloated have usually gone by day 2.

N\N recommends anti-inflammatory foods and an adequate iron intake at this time.

Women lose on average between 30-40mls of blood with some heavy bleeders losing more than 80mls. For this reason N\N also suggests you take additional iron and vitamin C supplements.


Oestrogen levels start to rise and peak. Oestrogen has an influence on muscle growth, muscle strength and force production. It also aids with muscle damage caused by exercise. These protective qualities may be one the reasons why you are able to train harder and at higher intensities during this phase.

It is also worth noting that oestrogen has a positive effect on mood and energy, so you are more likely to feel enthused and motivated to exercise. From an exercise perspective, this is the best time to focus on traditional strength and muscle building, with some high-intensity intervals. The higher levels of oestrogen will help you recover from a greater training volume. N\N recommends that you should challenge yourself in this phase.


Prior to Ovulation, when oestrogen levels are high, appetite and energy intake are lower. Oestrogen is an appetite suppressant. It also improves insulin sensitivity and you use fat as a preferential fuel source, leading to more efficient use of glucose. This is one of the reasons why you can perform at greater intensities and are less tired.

At this time, you can ‘get away’ with eating more carbohydrates as they will be used more efficiently.


The time between ovulation and when your uterus lining starts to breakdown is considered a high hormone phase. This is when the effects of progesterone become more pronounced. Increases in progesterone are correlated with an increase in BMR of about 10%. This means you are burning an additional 100-250 kcals per day.

Before we celebrate the additional calories. It has been reported that progesterone has an appetite stimulating affect and woman often experience an increase in hunger during this phase. The additional calories we are afforded from an increased BMR, are often negated by the additional increase in food consumption. Some women increase intake by as much as 90-500 kcals per day; causing weight gain.


Progesterone lowers insulin sensitivity. With the low presence of oestrogen the body is more prone to storing fat. One theory to explain this is that it is making the woman’s body ready to meet pregnancy energy demands.

Oestrogen plays a role in appetite signalling so low oestrogen may trigger increased hunger. Acknowledging the fluctuations in appetite and hunger motivation will go a long way in helping you feel in control.

Many women write off their changes in hunger as being ‘all in their head', and often blame themselves for lack of willpower or motivation. While external factors such as lifestyle, stress and exercise habits will influence nutritional choices, understanding how your body fluctuates over a cycle will improve adherence and self-belief, two key components of behaviour change.


One of the most common symptoms of PMS is food cravings.

Most women have reached for a chocolate bar in the days leading up to their period. For those monitoring their diets, this can be hard (especially if the cravings are unmanageable). For many women there is a real, physiological drive to seek out these foods.

Multiple surveys have found that chocolate is the most frequently craved food during this time.

There are a few explanations for why cravings are so specific. The first acknowledges the role of progesterone driving up the appetite and hunger response. In order to meet the change in BMR the body seeks out high energy dense foods.

Food sources such as chocolate, crisps and high GI carbohydrates may offer a ‘quick fix’ to deal with the hungry gremlins.

In some women blood sugar instability may be the culprit. As mentioned above, progesterone causes insulin insensitivity and some women may be more sensitive to the change in their blood sugar levels leading to cravings. If you cave into impulses and indulge in highly refined carbohydrate or fatty food, then this too will impact on blood sugar levels which in turn further exacerbates this issue.

A drop in serotonin is also be a viable explanation. Serotonin has a positive impact on our mood and general feelings of wellbeing. It has a close relationship with oestrogen. Oestrogen helps to increase serotonin’s receptor sensitivity, receptor levels and production. With oestrogen levels dropping to low levels it may trigger serotonin levels to drop below a level of optimal function causing mood destabilisation. While ‘moodiness’ isn’t a physical causation of cravings, the altered psychological state may motivate women to eat comfort foods and chocolate to simply feel better.

Lastly, the specific craving for chocolate may be explained by the sensory experience that it offers and the micronutrient magnesium. If the brain is seeking out sugary, fatty foods that offer feelings of comfort and love than there is no better food on the planet to do so.

At a physiological level magnesium deficiency, or low magnesium levels has been correlated with PMS. Chocolate contains high levels of magnesium and small levels of tryptophan (which helps makes serotonin) therefore has a mood-altering affect.

While this is great news, it is not a green light to eat large quantities of it. It is after all still full of calories, sugar and fat. But including appropriate portions of high-quality dark chocolate into your daily intake may assist you in feeling good and staying on track.

If you don't already do so, you could use a tracking app (such as Period Tracker) to track your cycle, moods, appetite and other information.

Ultimately, the more subjective data there is, the easier it will be for you to make informed choices.


© 2019 Nutrition Nailed



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