Why Women Should Eat Before They Train
Why breakfast is the pre-workout women should never skip
Well-known Physio Dr Stacy Sims' female guide to fuelling before the gym for better endurance and lasting muscle gain.
Fasting has been a trend for years, with more than 200 million people worldwide currently giving it a go. This weight-loss/maintenance strategy has had a fairly long run, and for men, might be here to stay.
What Happens In The Body When We Fast?
When a person fasts for 8-12 hours, their insulin and glycogen levels (stored carbs) begin to deplete. This forces the body to rely on different energy sources.
What Happens to Men and Women When We Train Fasted?
A 2025 study found that when men fast for 8-12 hours before they train, their performance actually improved. But women who fasted were typically left feeling more jittery and weak.
What Happens When Men Train Fasted?
Science and various studies show that it is far more beneficial for men to train fasted as opposed to women. This is because, when the male body endures the physical stress of a workout, it becomes more metabolically flexible and can take energy from fat reserves more efficiently.
What Happens When Women Train Fasted?
Fasted training for women is not only pointless and unhelpful, it's also detrimental. Women are already naturally more metabolically flexible than men because of our higher estrogen levels and general biological makeup. This means our bodies can take energy from fat reserves easily without needing to fast.
Research shows women’s fat-burn rate can be ~30–45% higher than men at similar exercise intensities, and that fuelling yourself beforehand supports this. We burn more fat during exercise, even without fasting.
How Are Womens Cortisol Levels Impacted During Fasted Training?
Women's cortisol levels naturally increase in the morning, which is why we tend to wake up earlier. Paired with a high-impact workout, it's the perfect way to start your day feeling stressed. Dr Stacey Sims, a well-known exercise physiologist, says the body naturally interprets morning fasts as a threat. Its coping mechanism is to send your intternal system into a catabolic state.
What Is A Catabolic State?
A catabolic state is when the body goes into starvation mode and starts breaking down muscle and storing more fat. This is not good for your body and interferes with your its natural muscle recovery process.
What Does Fasted Training Do to The Female Body?
Fasted training doesn't deliver the same metabolic benefits for women that it has proven to for men. This is because women have very different metabolisms. Women's metabolisms are actually more flexible, meaning our bodies can switch between different energy sources very easily.
When women train fasted, this puts physiological stress on the body, often negatively impacting our training.
How Else Can Training Fasted Impact The Female Body?
Training on an empty stomach also has other negative effects on the female body.
It can also cause:
- Destabilised blood sugar
- A disrupted hormone balance
- Compromised muscle recovery
These typically present as fatigue, increased anxiety, stalled progress, and, for women tracking cycle health, disrupted female hormones over time.
Your cortisol and estrogen levels get thrown off when the female body is placed under such stress. This is because our bodies are designed to always prioritise survival.
How Will Eating Before the Gym Improve Your Workout?
A small amount of food before training can make a huge impact, settling your nervous system and calming your body's stress response right away. Protein intake provides the amino acids tryptophan and tyrosine, specifically, which produce serotonin and dopamine.
This blunts the cortisol spike, stabilises blood sugar, and shifts the body from a state of protection into a state of performance. Insulin sensitivity improves. Energy levels hold. Muscle recovery starts from a better baseline.
What Should Women Eat Before The Gym?
This doesn't mean you need to tuck into a full-English feast every morning. Breaking the fast can be as simple as eating a piece of fruit, peanut butter on toast or a homemade breakfast bar. Dr Sims keeps her recommendation simple:
Which Foods Are The Best Pre-Workout?
- Greek yoghurt with honey
- Peanut butter on toast
- A protein coffee
- Protein oats
The goal is to have enough food to let your nervous system know in the morning that it's safe, and give your muscles something to work with.
Which Food Groups Are The Best Pre-Workout?
Pre strength training: 15g protein before strength training
Pre cardio / HIIT: 15g protein + 30g carbohydrates
If you're looking to break out of your long-standing plateau, you need to break your fast first. For an actionable guide including a gym girl breakfast edit backed by nutritionists, get yours here or through the link below.
Knowledge credit of Dr. Stacy Sims. Watch Dr. Stacy Sims YouTube Video on this now. More at heroptimal.co.uk
For more women's health content covering fitness and nutrition, head to our Physical Health Blog.
