Exploring Fasted vs Fed Training and Body Composition

In today's episode, I had the chance to speak to muscle physiology researcher and science communicator Dr. Lauren Colenso-Semple. Together, we unpack the common claims around hormones and training—from whether you should change your workouts based on your cycle, to the real effects of fasted cardio and birth control on performance and muscle growth. We also explore how menopause affects body composition, what the science actually supports when it comes to training differences between men and women, and why some of the most persistent myths about women’s physiology are based more on assumption than evidence.

What You’ll Learn:

• Why women’s physiology is not a limitation for building muscle
• Whether training around your menstrual cycle or avoiding fasted workouts is necessary
• The truth about oral contraceptives and their impact on performance, hypertrophy, and strength
• How menopause affects body composition—and what you can do about it
• Why consistency and progressive overload matter more than hormone fluctuations
• How much protein and resistance training women actually need—and when to eat it

This conversation is for every woman who’s been told her physiology is too complicated to train effectively. It’s not. The science is finally catching up—and Lauren is helping lead the charge.

This episode is brought to you by:

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Find Dr. Colenso-Semple at:

• Instagram - @drlaurencs1
• LinkedIn - https://www.linkedin.com/in/laurencolensosemple/
• X/Twitter - @drlaurencs1

Find me at:

• Instagram:@drgabriellelyon  
• TikTok: @drgabriellelyon
• Facebook: facebook.com/doctorgabriellelyon
• YouTube: youtube.com/@DrGabrielleLyon
• X (Twitter): x.com/drgabriellelyon
• Apply to become a patient – https://drgabriellelyon.com/new-patient-inquiry/
• Join my weekly newsletter – https://institute-for-muscle-centric-medicine.ck.page
• Get my book – https://drgabriellelyon.com/forever-strong/

Timestamps:

00:00 – Introduction to the episode and what it covers: hormones, menstrual cycles, birth control, and muscle growth.

01:00:29 – Training volume and progressive overload: what actually matters for hypertrophy.

01:02:51 – Fasted training and cortisol: where the fear-based messaging comes from.

01:03:16 – Is cortisol really a threat to muscle mass? Understanding its role in training.

01:04:29 – Fasted cardio vs. fed training: performance outcomes and the science.

01:05:09 – The reality of cortisol fluctuations and why it’s not something to fear.

01:06:37 – What research shows about fasted training and body composition in women.

01:07:31 – Debunking the idea that fasted training leads to fat gain or muscle loss.

01:11:06 – Should postmenopausal women avoid high-intensity training? The science says no.

01:13:02 – Protein timing: does it matter if you eat before or after training?

01:17:00 – Carbohydrate vs. fat intake: what matters more for body composition?

01:20:30 – Menopause and midlife body composition changes: what’s actually driving fat gain?

Disclaimer: The Dr. Gabrielle Lyon Podcast and YouTube are for general information purposes only and do not constitute the practice of medicine, nursing, or other professional health care services, including the giving of medical advice, and no doctor/patient relationship is formed. The use of information on this podcast, YouTube, or materials linked from this podcast or YouTube is at the user's own risk. The content of this podcast is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Users should not disregard or delay in obtaining medical advice for any medical condition they may have and should seek the assistance of their health care professional for any such conditions.