About this Video

• Video Title: Exercise while Fasting - How to time your workouts with fasting | Jason Fung
• Channel: Jason Fung
• Speakers: Jason Fung
• Duration: 00:09:24

Introduction

This video addresses common concerns about exercising while fasting. Dr. Fung explains the body's ability to use stored energy during fasting, dispelling the myth that fasting necessitates limiting exercise. He also discusses the optimal timing for workouts during a fast and the hormonal changes that make fasted-state training advantageous. A success story of someone who lost weight using fasting and exercise is shared.

Key Takeaways

• Yes, you can exercise while fasting: The body utilizes stored calories (body fat and blood glucose) for energy. Think of it like a hybrid car using different energy sources.
• Best time to exercise while fasting: Ideally, exercise should be done towards the end of your fasting period ("training in the fasted state"). This optimizes hormonal responses.
• Hormonal benefits of fasted-state training: Insulin levels decrease, signaling the body to use stored energy. Counter-regulatory hormones (like norepinephrine and growth hormone) increase, aiding in energy mobilization and muscle repair. The increased growth hormone, while seemingly counterintuitive during a nutrient-deprived state, ultimately contributes to muscle repair and growth upon eating.
• Muscle growth and fasting: While growth hormone increases during fasting, muscle growth occurs primarily after exercise when you consume protein. Combining fasted-state training with adequate protein intake maximizes muscle building.
• Importance of a coach/accountability: The video highlights the success of an individual who lost 50 lbs with the help of a coach, emphasizing the role of accountability in weight loss journeys.