Is Intermittent Fasting Sabotaging Your Muscle? The Truth About IF, Carbs & Recovery- Dr. Cas Fuchs
Optimal Protein Podcast with Vanessa Spina
Vanessa Spina
4.5 • 758 Ratings
🗓️ 1 December 2025
⏱️ 78 minutes
🧾️ Download transcript
Summary
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In this science-packed episode, Dr. Cas Fuchs breaks down the surprising ways intermittent fasting, under-fueling, cold plunges, and low glycogen can quietly sabotage your muscle, strength, and body recomposition goals. We uncover the truth about IF for active women, what really matters for protein timing and distribution, how carbs impact strength performance, and why ice baths may be blunting your gains. If you want evidence-based strategies for fat loss and muscle retention, this episode is essential listening.
If you loved Friday's solo episode on Why I Quit Intermittent Fasting, this conversation is the perfect follow-up — because Dr. Fuchs repeatedly emphasizes something Vanessa has discussed in detail 👉 We must prioritize high-quality human research over rodent-based nutritional myths.
Dr. Fuchs' work has directly shaped how we understand muscle growth, fat loss, glycogen replenishment, protein quality, cold exposure, heat therapy, and what actually matters when optimizing your body composition, not just your "healthspan."
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🔥 In This Episode:
• The truth about protein quality (and what actually matters for recomposition)
• Intermittent fasting, meal timing & the real anabolic window
• The truth about ice baths — and why they can blunt your gains
• Heat therapy: helpful or hype?
• Carbs, glycogen & why some workouts feel "flat"
• How much carbohydrate women really need to train at their best
• Aging, muscle loss & the inspiring 71-year-old lifter
• Dr. Fuchs' simple, science-backed formula for fat loss + muscle retention
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Follow @optimalproteinpodcast on Instagram to see visuals and posts mentioned on this podcast.
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The content provided in this podcast is for informational purposes only and should not be construed as medical advice. Consult with a healthcare professional before making significant changes to your diet or exercise regimen.
Transcript
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| 0:00.0 | Welcome to the Optimal Protein Podcast. I'm Vanessa Spina. |
| 0:04.7 | Welcome back to the Optimal Protein Podcast. I'm your host, Vanessa, and today I am thrilled to be |
| 0:10.3 | joined by Dr. Cass Fuchs, assistant professor at Maastricht University in a rising leader in the |
| 0:16.5 | field of exercise, nutrition, and metabolism. Dr. Fuchs' research explores how different proteins, |
| 0:23.1 | recovery strategy, and carbohydrate feeding approaches impact muscle protein synthesis, |
| 0:29.2 | glycogen replenishment, and ultimately driving our most optimal body composition. I learned |
| 0:36.3 | so much from the episode today, including how much glycogen |
| 0:40.7 | I need to actually replenish before I do my strength training because it makes a huge difference |
| 0:47.4 | in terms of the intensities that I can hit during my workouts. Now, he has published fascinating |
| 0:53.8 | studies on topics like if ice bass, |
| 0:56.9 | blood recovery. He actually did one of the first human studies and was one of the reasons that |
| 1:03.0 | people started realizing that ice bass might actually not be optimal for muscle growth. |
| 1:08.5 | Whether novel proteins can support muscle building, how older adults can |
| 1:13.2 | still achieve dramatic body recomposition through nutrition and training, and much more. His work |
| 1:19.6 | provides evidence-based insights for dieters, athletes, and anyone who's looking to improve |
| 1:26.0 | their metabolic health by losing fat, preserving lean mass, |
| 1:29.4 | and overall optimizing body composition. I am so excited for you all to hear this episode today, |
| 1:35.8 | and we are going to jump right in after this quick break. There is one supplement that I consider |
| 1:42.0 | absolutely foundational for women, and that is |
| 1:45.2 | creatine. And I don't say that lightly. Over the years on this podcast, I've interviewed some of |
| 1:50.4 | the world's leading protein and muscle metabolism researchers, and time and time again, |
| 1:55.7 | they recommend creatine for women. It's one of the most studied and effective supplements for fat loss, |
... |
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