Introduction

One of the most common “myths” we find ourselves having to address with potential new clients starting or restarting the Ideal Protein Phase 1 protocol is the idea that “you are not allowed to exercise in Phase 1.” This couldn’t be further from the truth. Not only can you exercise in Phase 1, but we highly encourage it!

While Phase 1 is not the ideal time to start training for a marathon, we know exercise has many benefits. Exercise can enhance weight loss by boosting metabolism and preserving lean muscle mass. And there are daily life benefits, like increased confidence, mental health and physical function. Our clients on Phase 1 deserve to participate!

The key to exercise in Phase 1 is doing the right kind of exercise. There is a way that you can leverage exercise that prioritizes fat as the primary fuel source, enhances mitochondrial function, and improves metabolic flexibility, making it effective for weight loss and metabolic health without excessive strain or risk of injury. This can be adapted to both the individual who has not ever really exercised regularly, as well as the experienced athlete!

So, let’s dive in and understand what type of exercise will work best for you to maximize your body’s ability to burn fat, improve your metabolic health and increase your level of fitness!

 Choosing the Right Exercise for Fat Loss

When starting an exercise plan, it’s crucial to define your goals and choose exercises that align with your nutrition plan to maximize results. For clients in Phase 1 of the Ideal Protein protocol, the primary goal isn’t just weight loss – it’s targeted fat loss while preserving muscle mass. Muscle isn’t just essential for movement; it’s metabolically active, burning calories 24/7 and playing a key role in your Basal Metabolic Rate (BMR). Unfortunately, without intervention, muscle mass naturally declines with age—12% per year after 50, and up to 3% per year after 60—a process known as sarcopenia. This loss leads to decreased BMR, increased insulin resistance, and potential weight gain.¹

Optimizing Fat Loss and Metabolic Health: The Benefits of Zone 2 Training During Ideal Protein Phase 1 The Ideal Protein Phase 1 protocol supports muscle preservation by providing adequate protein while restricting carbohydrates and fats, forcing the body to burn stored fat for energy. To maximize fat loss, the best exercise choices use fat as the primary fuel source while minimizing the need for glucose or glycogen. During Phase 1 ketosis, the liver maintains blood glucose by converting protein into glucose (gluconeogenesis). During this process, high-intensity exercise can increase glucose demand, forcing the body to break down muscle protein—the very thing we aim to preserve. To prevent muscle loss, high-intensity activities like HIIT, heavy weightlifting, and intense cardio should be avoided during this phase. By choosing the right exercise, clients can enhance fat loss, protect muscle, and optimize their metabolism throughout their weight loss journey.

Understanding the Hybrid Energy Model of the Human Body

Your body is the original hybrid machine, designed to efficiently switch between fat and carbohydrates for energy. This ability, known as metabolic flexibility, allows your body to use the most efficient fuel based on activity demands. Fat: The Efficient, Clean-Burning Fuel Fat metabolism, or beta-oxidation, occurs in the mitochondria—the “powerhouse of the cell.” Though slower than carbohydrate metabolism, fat oxidation yields more ATP (energy) per gram, making it the body’s preferred fuel during low-intensity activities. It provides consistent, efficient, and clean energy when oxygen is available. Glucose: The Fast but Dirty Fuel Carbohydrates can be burned without oxygen and provide rapid energy both in the cytosol and mitochondria, making them the go-to fuel for high-intensity activities. However, glucose metabolism produces more metabolic waste (reactive oxygen species, or ROS), making it a less efficient, “dirty” fuel. Like a hybrid vehicle, your body prioritizes fat for steady, sustained energy and glucose for quick bursts when needed. A metabolically flexible system seamlessly shifts between these fuels, optimizing energy use for different demands. When you begin exercising at low intensity, metabolic testing shows that you burn more fat than carbohydrates. As intensity rises, a crossover point appears where your body switches to burning more carbs than fat to meet increasing energy demands.

Keto-Adaptation: Becoming a Fat-Burning Machine

When clients begin Phase 1 of the Ideal Protein protocol, their main goal is to lose body fat. Most arrive with a metabolism stuck in sugar-burning and fat-storage mode due to a lifetime of high-carb eating. This reliance on carbohydrates keeps insulin dominant, preventing efficient fat burning.

To reverse this metabolic state, we significantly restrict carbohydrate intake. Within days, insulin levels drop, allowing glucagon to take over and trigger ketosis—a metabolic state where the body burns fat for energy. To ensure most of this fat comes from stored body fat, rather than dietary fat, we also limit fat intake while maintaining adequate protein to preserve muscle mass. This strategic balance fuels the extraordinary fat loss and muscle preservation seen in our clients.

Keto-adaptation occurs when the body consistently remains in ketosis for 3–4 weeks, steadily improving its ability to burn ketones and fatty acids for energy. As muscles adapt to using fat as their primary fuel, more ketones become available for the brain, unlocking numerous benefits:

Consistent Energy – A steady fuel supply from fat and ketones prevents energy crashes.

• Weight Management – Stored fat becomes the body’s primary energy source, aiding weight loss.

• Reduced Inflammation – Ketones have anti-inflammatory properties, promoting better health.

• Improved Mental Clarity – Many people report sharper cognitive function and focus in ketosis.

• Stable Blood Sugar – Ideal for those with insulin resistance or diabetes, preventing glucose spikes.

During Phase 1 of the Ideal Protein Metabolic Reset, these metabolic benefits enhance both physical and mental performance, bringing clients closer to their health and life goals. That’s why we say Ideal Protein “Powers Life Possible!”

Fueling Considerations During Exercise

Now that we understand Phase 1’s fat-burning power, let’s apply this knowledge to exercise selection.

Aerobic vs. Anaerobic Exercise

Exercise falls into two main categories based on how the body produces energy.

Anaerobic (“Without Oxygen”) – High-intensity, short-burst activities that demand quick energy from glucose or stored glycogen. Examples include weight training, HIIT workouts, sprinting, and activities like Orange Theory.

Aerobic (“With Oxygen”) – Lower-intensity, sustained activities that efficiently burn fat for fuel. These include walking, jogging, cycling, rowing, using the elliptical, rebounding, and swimming. However, if intensity increases beyond a certain threshold, the body will shift to anaerobic metabolism, requiring glucose.

Choosing the Right Exercise for Fat Loss – Don’t Get Caught in the “Black Hole!

In his recently published book, Born to Walk, former professional triathlete and world-renowned nutrition and fitness expert Mark Sisson argues that many runners seeking fat loss unknowingly train at heart rate zones too high to burn fat efficiently. He explains that many people fall into the trap of fitness marketing and influencers who promote the idea that “harder is better.” As a result, beginners looking to lose weight often start running in the traditional “cardio” heart rate zone—where their bodies primarily burn glucose from stored glycogen instead of fat.

Sisson highlights a common pitfall: Not only do many runners fail to burn unwanted fat, but they also risk losing muscle mass by consistently training above their optimal fat-burning zone. Running at too high an intensity can become a catabolic activity, breaking down muscle tissue rather than preserving it. Additionally, “chronic cardio” can create an imbalanced catabolic state, leading to excessive free radical production, connective tissue inflammation, and a reliance on carbohydrate energy. In response, the body may trigger compensatory mechanisms such as overeating, fatigue, and even increased fat storage.7,

Exercising at a level just above fat-burning but not intense enough to improve endurance is known as the “physiologic black hole.” This is where many beginners, fitness enthusiasts, and even athletes waste time and energy—burning glycogen instead of fat while putting unnecessary stress on their physiology, often with little to show for their efforts.

The human body is genetically designed for walking far more than running. If fat loss is your goal, the most effective strategy is exercising in the heart rate zone that optimizes fat burning —commonly referred to as Zone 2 training.

“Slowing down is going to require bravely navigating past rigid beliefs and behavior patterns that you’ve developed through exposure to flawed science, marketing hype, and peer pressure.” — Mark Sisson, Born to Walk

To align with Phase 1’s fat-burning state, the best exercises are aerobic activities that keep your metabolism in fat-burning mode. The key is to maintain an intensity that allows you to stay in Zone 2, without crossing into glucose-burning territory, which could slow your progress.

Best Exercises for Fat Loss

Choose activities you enjoy and can sustain consistently to support your weight loss and metabolic goals.

If you haven’t exercised in a long time, walking is perfect to ease into movement and begin building cardiovascular endurance. It is one of the easiest and most accessible ways to get started—it requires no equipment, can be done almost anywhere, and is gentle on the joints. If you were already training prior to starting Ideal Protein, other great choices include:

• Cycling
• Elliptical training
• Rowing
• Rebounding (mini trampoline)
• Swimming

By focusing on low-intensity, steady-state exercise in Zone 2, you can maximize fat loss, preserve muscle, and improve overall metabolic health—without falling into the “black hole” of ineffective cardio training.

What is Zone 2 Training?

One of the simplest and most effective ways to measure exercise intensity —especially for aerobic workouts—is by tracking your heart rate.

Since aerobic exercise strengthens your heart and cardiovascular system, monitoring heart rate helps gauge how efficiently oxygen is delivered to muscles for fat oxidation and ATP production.

Heart rate training zones, first introduced by Dr. M.J. Karvonen in 1957, help guide people toward optimal intensity for specific goals. The widely used formula 220 minus your age estimates maximum heart rate, dividing intensity into five zones. (see diagram)

Zone 2 Training (60–70% of max HR) is key for endurance and fat burning. While all exercise burns a mix of fat and carbohydrates, Zone 2 prioritizes fat as the primary fuel. At the upper end of Zone 2, metabolism begins shifting toward greater carbohydrate reliance, making this zone the ideal balance for maximizing fat oxidation while sustaining performance.

Zone 2 training is “ideal” during Phase 1 protocol because the intensity is high enough to stimulate positive metabolic changes, like improved fat burning and better insulin sensitivity, but still low enough that even people starting at lower levels of fitness can exercise in this zone for extended durations without excessive strain or risk of injury.

The Metabolic Benefits of Zone 2 Exercise

Zone 2 training enhances blood sugar regulation and fat-burning efficiency. It helps muscles clear glucose from the bloodstream, reducing blood sugar spikes—making a post-meal walk an excellent way to maximize this benefit.¹⁸

Since fat is the primary fuel for Zone 2 exercise, consistent training improves your body’s ability to burn fat, even at higher intensities. These benefits stem from Zone 2’s impact on mitochondria, the energy-producing powerhouses of muscle cells, making your metabolism more efficient over time.Zone 2 Training Effects on Mitochondria Training consistently with your heart rate in Zone 2 has amazing physiological effects on your mitochondria which include:

• Enhanced Mitochondrial Biogenesis: Exercise promotes the formation of new mitochondria, increasing mitochondrial density and overall capacity for energy production.
• Improved Mitochondrial Efficiency: Exercise enhances the function and efficiency of existing mitochondria, leading to better energy production and utilization.
• Increased Enzyme Activity: Exercise boosts the activity of mitochondrial enzymes involved in oxidative phosphorylation, improving the muscle’s ability to generate ATP aerobically.
• Enhanced Oxygen Consumption: Exercise increases the mitochondrial capacity for oxygen consumption, which is crucial for sustained aerobic energy production.
• Mitochondrial Dynamics: Exercise influences mitochondrial fusion and fission processes, promoting the formation of a healthy mitochondrial network and the removal of damaged mitochondria through mitophagy.

All of this translates into improvement to your metabolism’s ability to burn fat as its primary fuel not just for your daily activities, but at higher intensities than ever before during exercise!

Combining Phase 1 ketogenic nutrition with Zone 2 cardio creates a powerful synergy, enhancing fat utilization, insulin sensitivity, and blood sugar management.

Metabolic Efficiency Training

There are a growing number of endurance athletes who are taking advantage of the synergistic metabolic benefits of carbohydrate-restricted nutrition combined with Zone 2 style aerobic exercise to improve their “metabolic efficiency.” Metabolic efficiency refers to an athlete’s ability to burn fat at much higher intensities than previously thought possible while sparing onboard muscle glycogen stores during races. This approach allows endurance athletes to go further faster, and without having to “refuel” as much during an event.

The significance of this approach to increasing your body’s reliance on fat for fuel and decreasing its dependence on carbohydrate energy becomes clear when you understand:

The average individual can store only ~2,000 calories of carbohydrate energy (in muscles and liver as glycogen)

Yet the average person carries 80,000–100,000 calories of fat fuel Even very lean athletes (7–14% body fat) still carry 30,000+ calories of fat!

IInigo San Millán, PhD, a renowned exercise physiologist at the University of Colorado, has significantly contributed to understanding how different training intensities affect metabolism. He is best known for training 2024 Tour de France winner Tadej Pogačar, using an approach where up to 80% of training is in Zone 2! He promotes Zone 2 training for its ability to:

• Enhance fat oxidation
• Improve mitochondrial function
• Increase metabolic efficiency

His work is especially influential in encouraging low-intensity, steady-state exercise to optimize fat burning and health.

From a historical perspective, human hunter-gatherers relied primarily on fat as their fuel— especially during periods of food scarcity. It wasn’t until agriculture that we had constant access to carbohydrates. This shift made starches and sugars the dominant energy source, even though our biology hasn’t fully adapted. It’s estimated that high-carb nutrition has existed for only 0.5% of human history.4, 12

Practical Applications: How to Incorporate Zone 2 Training into Your Phase 1

Exercise should support your progress on the Ideal Protein Protocol, not hinder it. Follow these key guidelines to stay safe and maximize results.

If You Are Not Currently Exercising:

Consult your doctor if you have heart issues or haven’t exercised regularly.

Start slowly with light activities like walking, gradually increasing intensity.

Begin with 20 minutes – 3 times a week.

If You Are Already Exercising:

You should not feel any decrease in exercise tolerance while in Zone 2.

Avoid the urge to increase your intensity (you will see the benefits soon).

Center your work out around “Zone 2”.

How to “Get into the Zone”

220 – Age = Maximum Heart Rate (MHR)

MHR × 0.60 = Lower Zone 2 Limit

MHR × 0.70 = Upper Zone 2 Limit

For a 50-year-old:

220 – 50 = 170 bpm (MHR)

170 × 0.60 = 102 bpm

170 × 0.70 = 119 bpm

 Zone 2 Heart Rate Range: 102 – 119 bpm

Track your heart rate using a wearable like an Apple Watch, Garmin, or Fitbit to ensure your pace keeps you in this range.²

Walking briskly is an ideal starting point, but casual strolls (e.g., stopping frequently with a dog) may be too slow.

Jogging may push an untrained individual above Zone 2, but with consistency, it becomes easier to stay in Zone 2.

Using the “Talk Test”, you should be able to speak in full sentences during your workout. If you can only talk in short bursts, you’re going too hard

All Clients Should Monitor Their Exercise Tolerance:

• Reduce intensity and consult your Ideal Protein coach if you experience:
• Extreme hunger
• A stall in weight loss or muscle mass

If you experience any of the following symptoms, make sure to consult your physician: Fatigue

Dizziness

Pain or cramps

Nutritional Adjustments:

• Preload electrolytes before exercise, especially to replace sodium lost in sweat
• Use the Ideal Protein BCAA drink immediately post-workout to aid muscle repair and curb hunger
• Tracking Your Progress:
• Keep a journal of both your food and exercise
• Work closely with your Ideal Protein coach to monitor results
• Use a body fat % scale to ensure fat loss while preserving muscle
• Let your coach help interpret your progress effectively

By following these guidelines, you can safely integrate Zone 2 exercise into Phase 1 while supporting fat loss and muscle maintenance.

Conclusion

 Combining Ideal Protein Metabolic Reset Phase 1 ketogenic nutrition with Zone 2 training creates a powerful synergy that:

• Enhances fat metabolism
• Improves insulin sensitivity
• Increases endurance

Whether you’re new to exercise or a seasoned athlete, adopting Zone 2 training will optimize your fat loss and metabolic health during the protocol. And once you’ve reached your weight loss goal, it can set you on a new active lifestyle path.

If Tour de France cyclists and Ironman Triathletes use Zone 2 training for up to 80% of their workouts… Why shouldn’t you? Stick with Zone 2 during Phase 1, and you’ll see transformative results in both your fitness and metabolic health! 9

References

1 Von Haehling, S., Morley, J. E., & Anker, S. D. (2010). An overview of sarcopenia: Facts and numbers on prevalence and clinical impact. Journal of Cachexia, Sarcopenia and Muscle, 1(2), 129–133.

2 Wilcox, G. (2005). Insulin and insulin resistance. Melbourne Pathology, Collingwood, VIC; Monash University Department of Medicine & Clinical Nutrition & Metabolism Unit, C/- Body Composition Laboratory, Monash Medical Centre, Clayton, VIC.

3 Ma, S., & Suzuki, K. (2019). Keto-adaptation and endurance exercise capacity, fatigue recovery, and exercise-induced muscle and organ damage prevention: A narrative review. Sports, 7(2), 40.

4 Volek, J. S., Noakes, T., & Phinney, S. D. (2015). European Journal of Sport Science, 15(1), 13–20.

5 Maffetone, P. (2016). MAF exercise heart rate: performance. Maff Fitness Pty Ltd.

6 Maffetone, P., & Laursen, P. B. (2020). Rethinking fat as a fuel for endurance exercise. How it can help improve health and sports Maximum aerobic function: Clinical relevance, physiological underpinnings, and practical application. Frontiers in Physiology, 11, 296.

7 Sisson, M., & Kearns, B. (2025). Born to Walk: The broken promises of the running boom, and how to slow down and get healthy—One step at a time. Primal Blueprint Publishing.

8 Maffetone, P. B., & Laursen, P. B. (2016). 2(24).

9 Athletes: Fit but unhealthy? Sports Medicine – Open, Ignaszewski, M., Lau, B., Wong, S., & Isserow, S. (2017). The science of exercise prescription: Martti Karvonen and his contributions. BC Medical Journal, 59(1), 38–41.

10 Yan, Z., Lira, V. A., & Greene, N. P. (2012). Exercise training-induced regulation of mitochondrial quality. Exercise and Sport Sciences Reviews, 40(3), 159–164.

11 Seebohar, B. (2014). Metabolic efficiency training: Teaching the body to burn more fat (2nd ed.). Fuel4mance, LLC.

12 Sisson, M. (2009). The Primal Blueprint: Reprogram your genes for effortless weight loss, vibrant health, and boundless energy. Primal Blueprint Publishing.

Presented by the Ideal Protein Scientific Advisory Board

Dr. Chanh Tran Tien Co-Founder of Ideal Protein Inc. / Ideal Protein Board of Directors Co-Founder of Ideal Protein Company Inc./ Ideal Protein Board of Directors Dr. Tran is a physician specializing in nutrition, the psychology of weight loss, sports medicine and biology. He co-founded Ideal Protein and has been prescribing the protocol for his patients since 1988. He has written three influential books on the treatment of obesity and obesity-related issues.

Dr. John Barnes Scientific Advisory Board Member Dr. Barnes is the Clinic Director, Chiropractor, and Ideal Protein Head Coach at Reset Wellness. In private practice since 1996, he became an Ideal Protein coach in 2015 after his own success with the protocol. He has led a team helping clients lose nearly 30,000 lbs and improve metabolic health. He holds degrees from William & Mary and New York Chiropractic College, is a Certified Personal Trainer, and joined Ideal Protein’s Medical/Science Advisory Board in 2024.

Dr. Douglas W. Rothrock Scientific Advisory Board Member Dr. Rothrock is a practicing cardiologist who is Board Certified in Cardiology, Obesity Medicine, and Internal Medicine. He is Board Eligible in Sleep Medicine & Electrophysiology. He has spent the last 25 years of his career working as an interventional cardiologist in California, Oregon, and Arizona. He has used IP in his clinic since 2011.

Mr. Michael Ciell Scientific Advisory Board Member Mr. Ciell, a 1989 Honors graduate of the University of Florida’s College of Pharmacy, is a registered pharmacist certified in geriatric pharmacy. After eleven years in community pharmacy, he became chief pharmacist for “ECKERD-ON-CALL” in 2000. In 2006, he helped launch Ideal Protein of America, where he now serves as Senior Science Advisor and Executive Medical Board Member, focusing on health through nutrition and Metabolic Syndrome.

© Copyright 2025– Ideal Protein Company of America, Inc. All Rights Reserved. /TM/MD/MC Trademarks of Ideal Protein Company of America, Inc. Optimizing Fat Loss and Metabolic Health: The Benefits of Zone 2 Training During Ideal Protein Phase 1

Further Resources & Special Thanks A special thanks to Mark Sisson who’s work has been a terrific source of inspiration for me and especially as we wrote this guide. A true pioneer in the world of ancestral health and performance, Mark is a New York Times bestselling author of groundbreaking books like The Primal Blueprint, Primal Endurance, and his latest release, Born to Walk.

Note by Zan: Research on the female body is now revealing that women do need to exercise differently than men. Thank you to Dr Stacy Sims for leading the way in this area. https://www.drstacysims.com/ The above recommendations are for Phase 1 when you are in 24/7 fat burning and using your body fat for energy. For Phase 2 and 3 I believe the recommendations for women are quite different than men. And it’s time we stop using male data to guide women. “Women are not small men” as Dr Stacy Sims says.

The over reliance on cardio to stay “thin” is not healthy. Women need to lift heavy weights and do short sprints to ensure they don’t lose muscle mass and for many other reasons Dr Stacy Sims covers. Make sure you get the best information for you as a woman. She also covers why intermittent fasting is not a good idea for most women.

We offer 1:1 coaching to support you to reach your goals. We meet you weekly on zoom, we ship Ideal Protein foods directly to your home. We have helped thousands of clients lose weight and learn how to keep it off for good.