Should Women Workout Fasted?

Training fasted, particularly in the morning, has gained popularity as a method to maximize fat loss and enhance metabolic flexibility. It’s important to acknowledge that men and women are built differently. So what may be working for your boyfriend or husband or guy friends might not be exactly what's going to work for you. Here are some reasons why the gals should reconsider training on an empty stomach.

1. Hormonal Balance and Its Impact on Performance

Women's hormonal cycles are more complex than men's, largely due to fluctuations in estrogen and progesterone throughout the menstrual cycle. These hormones influence everything from energy levels to how the body metabolizes carbohydrates and fats.

Training fasted can exacerbate hormonal imbalances, especially in the follicular phase (the first half of the menstrual cycle) when insulin sensitivity is higher. Without sufficient fuel, cortisol levels—a stress hormone—can spike, potentially leading to muscle breakdown, increased fat storage, and a disrupted menstrual cycle. Long-term, this can contribute to hormonal issues like amenorrhea (absence of menstruation) or polycystic ovary syndrome (PCOS).

2. Reduced Performance and Recovery

Women generally have a lower fasting tolerance compared to men due to their higher reliance on carbohydrates for fuel, particularly during high-intensity workouts. Without adequate glycogen stores, which are depleted overnight, women may experience reduced energy, leading to decreased performance and less effective workouts.

Additionally, training in a fasted state can impair recovery. Post-workout nutrition is crucial for muscle repair and growth, and if the body is already in a state of energy deficit, it may struggle to rebuild muscle tissue effectively. Over time, this can result in decreased muscle mass, reduced strength, and a higher risk of injury.

3. Negative Effects on Metabolism

While fasted training is often touted for its fat-burning potential, for women, it might have the opposite effect. When the body is deprived of food, it goes into conservation mode, potentially slowing down the metabolism. This is particularly concerning for women, as they are more prone to metabolic adaptations that can lead to difficulties in losing weight or maintaining a healthy body composition.

Moreover, women are more susceptible to the adverse effects of prolonged calorie deficits, including thyroid dysfunction and decreased leptin levels. Leptin, a hormone that regulates hunger and energy balance, can drop significantly when fasting, leading to increased hunger and cravings later in the day.

4. Mental and Emotional Well-being

Training fasted can also have mental health consequences, particularly for those already dealing with societal pressures regarding body image and diet. Training on an empty stomach can lead to feelings of fatigue, irritability, and anxiety, which can diminish the overall enjoyment of physical activity. Over time, this can result in a negative relationship with exercise and food, potentially leading to disordered eating patterns or exercise addiction.

5. Better Alternatives for Women

Instead of training fasted, women might benefit more from a balanced approach that prioritizes nutrition and well-being. Eating a small meal or snack before a workout can provide the necessary fuel to perform optimally, maintain muscle mass, and support overall hormonal health.

Examples of some pre-workout snacks that are easy to digest before getting to work in the gym include: a banana with almond butter, a smoothie with protein powder and fruit, or a slice of whole-grain toast with avocado. You can even go as simple as adding protein powder and sweetened almond milk into your morning cup of joe. These options offer a mix of carbohydrates, protein, and healthy fats, ensuring that energy levels remain stable throughout the workout.

Conclusion

While fasted training may work for some individuals, it’s not a one-size-fits-all approach, especially for the gals. The potential risks—ranging from hormonal imbalances and decreased performance to metabolic issues and emotional well-being—outweigh the potential benefits. Ladies please consider fueling your bodies before workouts to optimize how you perform, how you feel afterwards and how you feel on a daily basis. Moving fuel to use  can help you reach your goals!

Resources

1.) Aird TP, Davies RW, Carson BP. Effects of fasted vs fed-state exercise on performance and post-exercise metabolism: A systematic review and meta-analysis. Scand J Med Sci Sports [Internet]. 2018 May [cited 2024 Aug 25]; 28 (5): 1476-1493. Available from: https://pubmed.ncbi.nlm.nih.gov/29315892/ doi: 10.1111/sms.13054.

2.) Schoenfeld BJ, Aragon AA, Wilborn CD, Krieger JW, Sonmez GT. Body composition changes associated with fasted versus non-fasted aerobic exercise. J Int Soc Sports Nutr [Internet]. 2014 Nov [cited 2023 Aug 1]; 11(1): 54. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4242477/ doi: 10.1186/s12970-014-0054-7. 

3.) Cowley E, Olenick A, McNulty K, Ross E. “invisible sportswomen”: The sex data gap in sport and exercise science research. Women in Sport and Physical Activity Journal [Internet]. 2021 Sept [cited 2023 Aug 1]; 29 (2): 146–51. Available from: https://journals.humankinetics.com/view/journals/wspaj/29/2/article-p146.xml doi:10.1123/wspaj.2021-0028

4.) Huberman, Andrew, host “Dr. Stacy Sims: Female-Specific Exercise & Nutrition for Health, Performance & Longevity,” Huberman Lab, 25 Aug 2024. https://www.hubermanlab.com/episode/dr-stacy-sims-female-specific-exercise-nutrition-for-health-performance-longevity