In this episode, Dr. Mikki Williden returns to The Athletes Compass to explore the Constrained Energy Model, a concept reshaping how athletes and coaches think about training and fueling. Drawing on the groundbreaking work of Dr. Herman Pontzer, Mikki discusses the biological limits of daily energy expenditure, and why the old model of "more exercise = more calories burned" often backfires, leading to fatigue, weight gain, and hormonal dysfunction. The conversation tackles RED-S, perimenopause, nutrient timing, energy availability, and the limits of tracking tools, all while emphasizing the importance of individual context, intuitive feedback, and informed nutrition.

1. The Constrained Energy Model posits that daily energy expenditure plateaus, even with increased exercise.
2. Energy is redirected from "non-essential" functions like immunity and reproductive health under high training loads.
3. Over-relying on devices or formulas to track calories burned can lead to overfueling, weight gain, or gut issues.
4. RED-S (Relative Energy Deficiency in Sport) can impair hormones, recovery, and bone health, especially in female athletes.
5. Basal metabolic rate (BMR) forms the majority of energy use, but varies with sex, age, lean mass, and training history.
6. Fueling needs are individual: what works for Michael Phelps or Killian Jornet won’t work for everyone.
7. Tools like calorie counters can be helpful for education, but not as rigid frameworks.
8. Protein and strength training are critical, especially for perimenopausal women looking to protect bone and muscle mass.

• Mikkipedia | Dr. Mikki Williden’s podcast, covering topics such as nutrition, fitness, and longevity.
• Paul Warloski - Endurance, Strength Training, Yoga
• Marjaana Rakai - Tired Mom Runs - Where fitness meets motherhood.