#1 Reason You’re Still Storing Fat & Exhausted (No Matter How Healthy You Eat) | Alan Couzens

In this podcast episode, Alan Couzens, an expert in endurance training and metabolic health, shares insights on fat metabolism, training zones, the role of low-intensity movement, and their broader implications on health and athletic performance. The conversation explores how metabolic dysfunction affects energy use, the importance of training the body to burn fat, and how this has profound effects on both everyday well-being and athletic outcomes. Alan also addresses the cultural myths around exercise intensity, the role of the nervous system in training adaptations, and how stress and nutrition interplay with metabolic health. Throughout, he offers practical advice for people across the spectrum—from elite athletes to those simply seeking better health.

Metabolic Dysfunction and Fat Burning

Alan opens by discussing the widespread metabolic dysfunction evident in modern societies, where many people are primarily reliant on carbohydrate metabolism even at low-intensity activities such as walking or resting. This carbohydrate dependence leads to unstable blood glucose levels, a cycle of cravings, and difficulty maintaining healthy body weight. He emphasizes that this is not a matter of psychological weakness but rather a metabolic issue: the muscles are simply not efficient at burning fat, which is an abundant fuel source in the body. Teaching the body to use fat for low-intensity efforts helps stabilize metabolism, reduce cravings, and ease overall nutritional control.

Training Zones and Movement Intensity

Alan reframes traditional training zones by incorporating "zone zero," a baseline state of easy movement that many athletes and coaches tend to disregard. Unlike the common belief that only moderate to high-intensity exercise "counts," Alan highlights that all movement matters metabolically, especially the lowest intensities where fat oxidation is maximized. Zone zero involves activities like casual walking and light yoga, while zone one involves gentle aerobic efforts that start improving cardiovascular function and maximal fat oxidation. Higher zones become sport-specific and focus on glycogen utilization for race efforts. The "gear" analogy helps people understand their daily movement intensity as varying levels, all contributing differently to metabolic health and fitness.

The Power of Low-Intensity Movement

Alan stresses that low-intensity movement produces substantial health and performance benefits. Even elite athletes with exceptional VO2 max values perform routine low-intensity activities such as walks to enhance recovery and maintain aerobic fitness. He shares examples of athletes who achieved remarkable race performances while spending a majority of their training time at walking pace. The physiological basis for this includes important cardiac adaptations, such as increased stroke volume and heart size, which occur because the heart reaches close to its maximal filling at surprisingly low intensities. Regular low-intensity activity also supports the parasympathetic nervous system and helps regulate stress responses.

Stress, Nervous System Balance, and Exercise Quality

A key theme in the episode is the interplay between stress, exercise intensity, and the autonomic nervous system. High-intensity workouts stimulate the sympathetic "fight or flight" system, increasing stress hormone release and making recovery harder. Low-intensity exercise, conversely, activates the parasympathetic "rest and repair" state, which promotes relaxation, metabolic stability, and better sleep. Alan points out that when life stress is already high, adding intense exercise can be counterproductive by overstimulating the nervous system. He champions listening to the body and tailoring exercise intensity according to personal stress levels, thereby enhancing long-term adaptation and health.

Redefining Exercise Success and Consistency

Alan challenges cultural myths such as "no pain, no gain" and the idea that intense, grueling effort is necessary for improvement. Instead, he promotes consistency and gradual progress through manageable intensity and volume. Using the example of endurance athletes, he points out that many amateurs adopt a counterproductive approach by pushing too hard too often, leading to injury and burnout. Elite athletes, conversely, skillfully adjust workouts in response to how their body feels, allowing sustainable long-term development. Alan emphasizes that beating one's long-term average by small increments leads to meaningful fitness gains over time.

Metabolic Health and Fat Loss Strategies

Addressing those interested in fat loss but not necessarily athletic competition, Alan identifies the core issue as the muscle's impaired ability to oxidize fat. Many dieters struggle not because of lack of willpower but because their muscles default to burning sugar. He highlights that fat stores on the body remain inaccessible fuel until muscles adapt to efficiently burn fat. The path to improving this ability starts not with intense gym sessions but with very easy, low-intensity movement combined with stress management techniques like yoga and simple breathing exercises. Only after improving metabolic flexibility can nutrition adjustments—favoring real foods and moderate carbohydrates—take hold more effectively.

The Role of Lactate and Its Relationship to Training Zones

Alan explains lactate as a byproduct indicative of carbohydrate metabolism, produced when muscles burn sugar anaerobically in the absence of sufficient mitochondria aerobic capacity. Testing blood lactate levels gives insight into whether the body is burning fat or carbs at various intensities. Low lactate corresponds to predominant fat burning, while rising lactate signals increased carbohydrate usage. Using lactate testing, Alan helps athletes identify their "zone one" – the threshold below which fat metabolism is maximized and training is most beneficial for metabolic health. High lactate for prolonged durations signals an excessive physiological stress and potential health risks if sustained.

Importance of Aerobic Muscle and Balanced Strength Training

Alan differentiates muscle fibers into slow-twitch (aerobic) and fast-twitch (anaerobic) types. He advocates for developing and maintaining aerobic muscle mass rich in mitochondria and capillaries, which supports metabolic health and fat burning. Excessive traditional strength training focused on hypertrophy fosters fast-twitch fibers, which rely primarily on sugar metabolism, potentially compromising aerobic capacity and overall health. His approach to strength training blends predominantly circuit-style, lower intensity work aimed at maintaining muscle mass and function, with smaller doses of heavier, neural-focused strength work to preserve fast-twitch fiber recruitment, without promoting excessive size gain that might reduce aerobic performance.

VO2 Max as a Key Marker of Health and Longevity

VO2 max—the maximal oxygen uptake per kilogram of body weight—is presented as a gold-standard indicator of aerobic fitness and predictive of longevity. Alan stresses that maintaining young-adult levels of VO2 max well into middle and older age is possible but requires consistent movement and tailored training. While elite athletes experience inevitable VO2 max declines with aging beyond genetics and peak capacity, the average person has significant room to improve or maintain aerobic fitness through effort and sustained activity. Alan's personal goal is to hold a VO2 max of around 50 ml/kg/min (typical for a fit young male) as he ages, viewing it as essential for functional longevity.

Tailoring Exercise According to Life Context and Stress

Alan highlights the importance of viewing exercise not as isolated sessions but integrated within broader life stress. For people in demanding jobs or high-stress periods, low-intensity, restorative movement such as walking or yoga can be more beneficial than pushing for high-intensity sessions. Conversely, when stress is low and recovery is good, more intense training can be added. He encourages monitoring physiological markers like heart rate variability to guide daily training decisions. This balanced approach mitigates risks of chronic overstimulation and injury, helping maintain consistency and enjoyment.

Practical Recommendations for General Health and Movement

For those with limited time or fitness starting from scratch, Alan recommends prioritizing one hour a day of low-intensity walking in nature combined with yoga or relaxation practices to engage the parasympathetic nervous system. This foundational level of movement supports cardiac adaptations, fat oxidation, stress management, and sleep quality. Once this base is established, adding modest amounts of strength training focused on functional, aerobic muscle preservation enhances overall health and mitigates age-related muscle loss. Alan reframes exercise as sustainable movement throughout the day rather than sporadic, hard efforts, making good health more accessible to all.

Exercise Intensity and Fueling Strategies

Alan explains the concept of matching carbohydrate intake to exercise volume and intensity. On sedentary days or with only low-intensity activity, carbohydrate consumption should be lower to avoid suppressing fat metabolism. Because the body preferentially burns the easiest fuel available, constant carbohydrate intake leads to reduced fat oxidation and metabolic inflexibility. Fasted morning walks before breakfast are recommended to enhance fat burning. As fitness improves and moderate-to-high intensity work increases, carbohydrate intake can be adjusted accordingly to support those efforts. Overall, the goal is to fuel appropriately without excess, focusing on real foods and metabolic adaptability.

Addressing the "Too Late to Start" Mindset

Alan emphatically reassures listeners that it is never too late to start improving health and metabolic fitness, even for people in their 40s, 50s, or beyond who may have neglected exercise previously. He shares examples of individuals who began serious endurance training later in life and achieved remarkable achievements such as Ironman age group wins. The key is adopting a long-term, consistent approach focused on sustainable low-intensity movement followed by gradual progression. He encourages listeners to think beyond short-term goals and embrace fitness as a multi-decade endeavor with evolving priorities.

Cultural Perspectives on Movement and Life Balance

The conversation touches on how modern work cultures and societal expectations often erode the time and autonomy necessary for consistent movement and health maintenance. Alan contrasts this with more flexible lifestyles where individuals have consciously prioritized control over their time to safeguard their health and fitness. He warns against the "trap" of chasing promotions or jobs that demand excessive hours at the cost of physical well-being. Ultimately, finding a balance that respects both professional ambitions and the body's needs for rest, movement, and recovery is vital for long-term success and quality of life.

Managing Injuries and Listening to the Body

Drawing on experience with elite athletes like Eliud Kipchoge, Alan highlights the importance of recognizing early signs of injury or fatigue and modifying training accordingly. Unlike many amateurs who persist rigidly with training plans despite niggles, elite performances arise from patience, body awareness, and timely adjustments. He stresses that avoiding prolonged injury downtime is crucial for continuous progression and longevity. This mindset allows athletes to maintain consistency over years and avoid the stop-start cycle of setbacks common in recreational populations.

Long-Term Perspective on Fitness and Aging

Alan stresses that fitness should be viewed as a lifelong journey rather than a short-term challenge. He cautions against explosive training ramps followed by burnout and inactivity. Instead, incremental improvements built over years yield sustainable gains in function, metabolic health, and resilience. Recognizing natural age-related declines, Alan advocates for increased training volumes with age to hold off losses in aerobic capacity. The goal is to age well and remain functional, independent, and active rather than merely chasing youthful athletic feats at all costs.

Accessing Alan Couzens' Work and Community

Listeners interested in exploring Alan's ideas further are encouraged to engage with his thoughtful writing on his Substack, where he has serialized his book and shared in-depth explanations and data visualizations. Alan remains somewhat active on Twitter and hosts an affordable community forum for personalized feedback and discussion about fitness and metabolic health journeys. He also offers coaching consultations for those seeking structured guidance. His work spans detailed exercise physiology concepts presented in an accessible, practical manner for broad audiences.