Why Fasting Is Likely Not For You

As more data emerges on women in sports, on our performance and recovery, we start to see how following previously available data (based solely on the male anatomy and physiology) has likely held us back from becoming the best version of ourselves. We could call this the age of re-learning as we are faced with cognitive dissonance – so much of what we know has, in fact, never applied to us. Getting the information out there on what’s optimal for women when it comes to pre- and intra-training nutrition will allow us to avoid lethargy and hormonal issues caused by overtraining and under-nourishing our bodies. Because, at the end of the day, we just want to be healthy, don’t we?

It is fairly simple to be healthy – we want to move our bodies regularly and eat a minimal amount of ultra-processed beige foods, which I refer to as matter as they’re very low on or devoid of important nutrients . And while it is simple, it doesn’t mean it’s cheap. In the world of Nutrition, it is widely known that one’s socio-economic status plays the biggest factor in the person’s health. It is considered a privilege to be able to try different diets, whether these are based on wilful calorie restriction or on cutting out whole food groups. Regardless of our intentions and goals, one thing is certain – when we move, we need to eat and Sports Nutrition tells us that it is really the timing of our nutrients that is most important. In order to improve our metabolic efficiency, we need to ensure our bodies are able to cope with the demands of our training regimes.

Where to look to for advice?

Different fasting protocols have gained popularity over the last 5-7 years and, just like with cold exposure, such trends and movements are often driven by high profile social media accounts. Most of these accounts belong to men, however there are also a few women who swear by such protocols and I am here to assure you that they have been getting their information from the same guys. Whether or not these individuals are actually qualified to give any such advice is rarely questioned and it is easy to forget that what works for one might not work for another. One individual’s anecdotal advice, no matter how convincing, applied to hundreds of thousands of people can actually pose a threat to the average everyday person’s health who simply wants to improve their quality of life.

Previous fasted training studies have been done on male data and we have learned that men, when moving, will go through blood sugar first, then liver and muscle glycogen and only then will their bodies target fatty acids. This is why fasting protocols and low carb/calorie diets allow them to tap into desired energy sources almost immediately and lose weight nearly twice as fast. I have witnessed this many times over whenever a male client has come to me to lose weight and in three months they will have dropped two stone (28lbs) easily while for the women this figure is usually half of that.

As new data comes out on fuelling performance, we are learning that women’s bodies use blood sugar first and then bodyfat – so, contrary to what we have believed to be true, it would seem that we are already at maximum fatty acid oxidation capacity. What makes this possible? For one, it’s the protein differences in the muscle – we tend to have lower lean body mass compared to men, which directly affects our glycogen storage, and therefore the need to use fat as fuel increases. However, it is also the changes in oestrogen and progesterone throughout our menstrual cycle that affect our insulin sensitivity, meaning that our bodies’ ability to interact with carbs changes constantly. However, one thing is guaranteed and this applies even whether you are on the pill, perimenopausal or menopausal – you are still capable of burning bodyfat without starving yourself and this is where the re-learning begins.

What is the solution?

Although the allure of fasted cardio and the promise of burning more calories on an empty stomach has tempted recreational athletes for years, for women there is a much better way to reach metabolic efficiency. Metabolic efficiency – utilising your body’s natural ability to burn energy and perform well based on how you eat. Men choose to train fasted to increase their ability to tap into their fatty acid storage, however we now know that women don’t need to be hungry to burn bodyfat. You can have protein and fats to power your workout and still utilise fatty acids, then have carbs later to replenish muscle glycogen stores for your next workout. This is called carb backloading and it is a very efficient way to drop bodyfat while building muscle. (I will cover different methods of carb manipulation in length in the next blog post.)

The success of a fat loss program boils down to one’s hypothalamus reading the stress from the body: Am I able to take this on? or Am I in a catabolic breakdown state?. If women are rationing their calories and putting their bodies under severe stress through training without adequate energy or fuel in the body, the body reads this as an attack and takes the woman into low energy availability state (LEA) and muscle breakdown starts. Men don’t experience this because they can get away with a lot less energy before their bodies start to have a disturbance to the hormones.

Let’s talk numbers

When we look at baseline calorie intake, we women are far more vulnerable to endocrine disruption. For men, hormone disruption and performance difficulties start from 15kcal per kg of fat free mass, which is exactly half of what we need to consume to keep our hormones and health intact. For women, hormone disruption can start to show from as high as 30kcal per kg of fat free mass.

To make these numbers make sense, let’s do some maths based on the average fit woman. If you have 50kg of fat free mass (expected bodyweight around 60-65kg) or 60kg of fat free mass (bodyweight 70-75kg), the disruption can begin from 1500kcal or 1800kcal respectively. For a man with 50kg or 60kg of fat free mass, his energy intake could reach a low of 750kcal or 900kcal before he starts to be affected by low testosterone and notices changes in their output.

Performance > societal norms

Women with higher than average muscle mass need higher than average nutrition and what is often thrown about as the average person’s daily energy intake (1800-2000kcal), only covers the bare minimum for a female athlete. Depending on your chosen sport, you might have to eat upwards of 3000kcal a day to optimally support your body’s growth. Eating below your Basal Metabolic Rate (BMR) will cause issues with your thyroid, affect kisspeptin levels that are directly related to you appetite, and after a mere 3-4 days you start to lose the luteinising hormone, which is directly related to our ovulation and can cause amenorrhea.

If we add to all this knowledge the societal norms where men are expected to eat more and to train from an early age and women have been encouraged to eat less and to not change their appearance into a more muscular one, we have ourselves a disastrous combination and the risk of millions of individuals potentially never finding out what they are physically capable of. To avoid this, we need to move away from fearing food and start nourishing our bodies appropriately. We also have to look at resistance training as the tool towards health and longevity and not some scary activity that might make us look like a man. (Allow me to be clear: you will never look like a man, unless you start to take steroids.) For best results in your training, you will benefit from a solid plan, which you will be able to nail down after months (or years) of observing your body and performance.

For now, I can confidently leave you with these few pieces of information: if your training sessions are as intense as can be, you will likely benefit from a rest day every 2-3 days. If taking days off does not sit right with you, I recommend you have a moderate intensity training day every 2 days while adapting your food intake accordingly. If your training is entirely based on performance, you are likely following a high carb regime and I won’t give you any additional advice for now. However, if you have been training fasted for quite some time, I would like to encourage you to start taking in a small amount of protein and fats before your training sessions. A 200-300kcal light snack up to an hour prior to moving yourself will ensure your body has fuel to keep it moving and amino acids to avoid muscle breakdown.

That’s it for today!

As always, I hope you have found this informative and that you are able to take away and apply this knowledge to your daily life. I thoroughly enjoy reading sports research and studies on women, our hormones and health and take pride in being able to share it all with you. Thank you for reading!

Rahel xx