Intermittent Fasting for the Female Runner

August 6, 2020

Intermittent Fasting for the Female Runner

Fasting has been used for centuries for health, religious and cultural reasons. But more recently, in the past 10-15 years we have become aware of FASTING as a way to promote good health, longevity and weight loss. There are so many different fasting approaches it can be difficult to know if FASTING would be health promoting for you as an individual and if it would help you as a runner.

So today we are going to talk about:

1. Overview of different FASTING approaches and their potential health benefits

2. The Pros and Cons of FASTING for the female runner

3. TIPS on how you may integrate a fasting food plan approach with your run training

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LISTEN HERE Episode 18: Intermittent Fasting and the Female Runner


Intermittent Fasting for the Female Runner


An introduction to the different categories of fasting i.e. Intermittent Calorie Restriction, (ICR) Alternate Day Fasting (ADF) and Time Restricted Feeding (TRF).


Discussing Intermittent Calorie Restriction, (ICR) Alternate Day Fasting (ADF) and Time Restricted Feeding (TRF) and associated health benefits e.g. weight loss, positive body composition changes, Increased energy and recovery, feeling brain sharp and having more clarity of mind alongside reduction in risk factors for metabolic health conditions (Type 2 diabetes, high blood pressure, unhealthy cholesterol levels, cardiovascular disorders).


How fasting works to give the health benefits you’ve discussed.


How to assess which one of these fasting approaches would be right for you.


When is fasting is not recommended – Health status and life stages


The pros and cons of fasting, especially for the female runner and a review of research and why it’s key to have the nutrition basics in place as a foundation before starting a fasting programme.


Ideas to help you synchronise intermittent fasting with your running life and training.


Typical questions people and runners ask about intermittent fasting:

Q. Can I drink coffee when I’m fasting?

A. Many of the fasting diet books may suggest it’s ok to drink black coffee but our word of caution is that remember coffee is a stimulant – it may affect adrenal hormones and stimulate cortisol and also trigger a release of fatty acids. So ideally avoid caffeine or drink decaffeinated.

Q. Is it ok to run in a fasted state?

A. Short easy “no stress” runs of less than 60 minutes are fine in a fasted state and will also help your body adapt to utilising fat as fuel. Ideally schedule early am before your fasting window.

Q. Do I have to follow a perfect healthy diet every day when fasting?

A. You’ll get better results if you follow a healthy food plan, however, be realistic, choose to have treats occasionally, it’ll help you sustain your food plan for the longer term. We tend to suggest an 80:20 approach.

Q. How much food should I eat when I’m on a fasting window e.g. 16:8?

A. That’ll really depend on your body composition/weight loss goals – if you are following 5:2 or Fast 800 you’ll be eating less in line with your food plan, however if you are not overweight but using TRE to promote fat loss and some performance benefits, we’d suggest you eat to your Energy Requirements i.e. don’t intentionally under eat – follow healthy plate and portions and adjust to your training distances but still eat within the time window you have determined.

Q. I’m worried that I’ll feel ill or have no energy for running when following Time Restricted Eating?

A. Aim to front load your calories/energy intake to the earlier part of your eating window/active part of your day. Don’t run fasted if you are planning a run longer than 1 hour or an intensive training session. Always aim to run inside your eating window e.g. if you plan to eat 10-6 don’t run at 9pm at night. Don’t forget to build in post run recovery fuelling within your eating window.

Q.What if I find I’m feeling weak when out on a run?

A. Be prepared. Take food/snack with you just in case. If you feel it’s required, don’t push through, refuel – it takes practice – and it’s not the end of the world if you need to respond – listen to your body – refuel and enjoy your run.

Q. What can I drink when on a fasting plan?

A. Water, herbal teas, occasional decaffeinated coffee, and avoid soft drinks, fruit juice and alcohol

Q. Would it help if I skipped meals?

A. Following a timed meal plan within your eating window will help support blood sugar balance and energy levels. So please avoid skipping meals. If a meal is delayed add in a protein rich snack to help balance blood sugar.


Intermittent Fasting for the Female Runner

Cortisol manages your energy by supporting blood sugar balance. If you haven’t eaten for a few hours and blood sugar drops too low the adrenals produce cortisol to signal production of glucose to bring blood sugar balance back into balance.

By not eating overnight since your last meal/snack you will have been in a fasted state. For some people there is a possibility that your blood sugar may be too low. That may lead to cortisol being activated to bring glucose from the body’s store to help provide energy and balance blood sugar. Sometimes that can lead to overall cortisol levels being higher than they need to be during the day.

For people with symptoms of blood sugar imbalance it may be advisable to eat within an hour of getting up. Signs and symptoms may be feeling dips in energy, tired all the time, jittery between meals, weight gain around the middle, foggy brain and there are others!

There are other factors which can affect cortisol levels e.g. caffeine, high sugar/carb food plan, skipping meals and STRESS.

The female factor (we believe) is that if we have a high requirement for cortisol then that takes priority over making female sex hormones and the knock on effect is disruptions to hormonal balance and all that goes with that e.g. periods, fertility, sex drive, peri and menopause and other hormonally driven health conditions. Known as CORTISOL STEAL.

However it is possible for your body to adapt to fasting and regulate blood sugar balance, so practice and adjust food intake and fasting times to get the best results for you.


Intermittent Fasting for the Female Runner

  • Never run on empty/fasted (unless it’s an easy run less than 60 minutes)
  • Plan your training runs within your “eating window”
  • Remember to build in post run recovery fuelling
  • ALWAYS healthy food (no processed/junk food)
  • Follow PLATE balance (macros and micros)
  • Have a timed routine for your meals/snacks within “eating window”
  • Front load calories – more at breakfast and lunch and less in evening i.e. eat calories around active part of day
  • Listen to your body – respond and adapt!
  • Personalise your plan – build your training around your “eating window” or vice versa

Related Episodes:

Nutrition Basics for ALL Runners

Run Lean Run Fast

Related Resources:


The suggestions we make during this episode are for guidance and advice only, and are not a substitute for medical advice or treatment. If you have any concerns regarding your health, please contact your healthcare professional for advice as soon as possible.

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