How Fasting Heals Hormones, Burns Belly Fat & Increases Sex Drive | Dr. Mindy Pelz

She highlights that poor metabolic health has become widespread due to lifestyle and environmental factors—highlighting the importance of metabolic retraining and detoxification. Central to reversing these trends is understanding the interplay of diet, environmental toxins, and hormonal shifts, particularly as we age. Dr. Pelz stresses that improving metabolic health is within reach, requiring practical changes rather than expensive interventions, and that intermittent fasting is a powerful tool in this effort.

Intermittent Fasting and the Metabolic Switch

A significant part of the conversation centers around fasting as a metabolic tool. Dr. Pelz explains the body operates on two fuel systems: the glucose-driven "sugar burner" system activated by eating, and the fat-burning system accessed during fasting. When one fasts for approximately 12 hours or more, the body begins to shift from glucose to fat as fuel, generating ketones, which serve as a vital alternative fuel for the brain.

The metabolic switch achieved through fasting therefore promotes fat burning, insulin sensitivity, and the production of ketones—fuel that helps energize brain function. Dr. Pelz recommends starting with manageable fasting windows, like 12 hours, pushing gradually toward 15 to 17 hours to stimulate deeper processes like autophagy. This fasting window stimulates the body's innate intelligence to detox and repair itself, promoting holistic health beyond mere weight loss.

Fasting Duration and Healing Benefits

Delving deeper, Dr. Pelz explains fasting is not a one-size-fits-all prescription but rather a scalable tool, with beneficial effects increasing alongside fasting duration. At 12-13 hours, the body begins fat-burning; by 17 hours, autophagy—a cellular self-cleaning mechanism—is activated for detoxification. Fasting for 24 to 36 hours amplifies gut healing and targets stubborn belly fat, a major concern for many.

Importantly, Dr. Pelz encourages a gradual approach to longer fasts, training the body incrementally to adapt. She stresses safety and personalization, noting not everyone will thrive on extended fasts and some individuals—due to genetics or existing health conditions—may need a tailored approach. The critical message is consistency and gradual adaptation, aligning with how our ancestors would have naturally fluctuated between feast and famine.

Menopause, Hormones, and Weight Gain

The podcast transitions to the profound hormonal changes women face during perimenopause and menopause, focusing on their metabolic consequences. Dr. Pelz reveals that declining estrogen levels disrupt insulin sensitivity, which contributes to the infamous "menopausal belly fat" despite unchanged diet or exercise habits. This hormonal shift creates a metabolic "off-ramp" causing weight gain that many women mistakenly blame on lifestyle alone.

She underscores the frustration women experience as they double down on diet and exercise only to find these strategies ineffective. The key, Dr. Pelz argues, is awareness of hormonal status and metabolic health, empowering women to adapt their lifestyle strategies accordingly. She suggests that fasting, combined with balanced nutrition aimed at stabilizing glucose and insulin, can mitigate menopausal weight gain, improve energy, and reduce symptoms such as brain fog and insomnia.

Fasting's Effects on Mental Health

A less commonly discussed benefit of fasting addressed by Dr. Pelz is its impact on brain health and mood regulation. As the brain shifts from solely glucose fuel to a mix including ketones, various neurotransmitters critical to emotional balance are stimulated. Fasting boosts GABA, the calming neurotransmitter, which helps reduce anxiety and promote mental clarity.

Furthermore, ketones influence dopamine, serotonin, and oxytocin pathways, which supports motivation, happiness, and social connection. Dr. Pelz explains that while initial fasting can provoke hunger-induced irritability, sustained adaptation results in enhanced mental clarity, calmness, and focus. This neurochemical shift not only benefits mood disorders but may help combat neurodegeneration associated with aging and metabolic decline.

Fasting, Muscle Preservation, and Exercise

One of the complexities addressed is reconciling fasting with the demands of exercise and muscle maintenance. Dr. Pelz acknowledges concerns around protein intake and energy levels, pointing out the lack of absolutes and emphasizing individual experimentation. Many find that light workouts in a fasted state improve performance, whereas others need to time nutrition around training.

She recommends prioritizing the quality and timing of protein during eating windows to support muscle repair. For example, in a 16:8 fasting protocol, individuals can consume adequate protein across two meals and snacks to meet their needs. The overarching advice is to listen to one's body and tailor fasting and fitness habits to personal energy and recovery patterns.

Detoxification and Environmental Toxins

Environmental toxicity and its interaction with metabolic health is a persistent theme. Dr. Pelz highlights that we live in the most toxic era in human history, with pollutants found in air, food, water, clothing, and even beauty products. One of the largest threats she names is glyphosate, a widespread herbicide now deregulated, linked to chronic diseases and endocrine disruption.

Fasting supports detoxification through the process of autophagy, where damaged cells identify and expel toxins including bacteria, viruses, pesticides, and plastics. Although heavy metals are more challenging to eliminate, regular fasting can reduce overall toxic burden. Dr. Pelz argues for prioritizing toxin reduction via lifestyle changes while acknowledging the difficulty of complete avoidance in today's environment.

The Impact of Fasting on Immune Function

Fasting's metabolic benefits translate into improved immune resilience and a reduction in chronic disease risk. By lowering hemoglobin A1c, a marker of long-term blood sugar control, fasting directly influences the trajectory of diseases like diabetes, cardiovascular illness, fatty liver disease, and even neurodegenerative conditions such as Alzheimer's.

Dr. Pelz emphasizes the interconnectedness of metabolic syndrome with chronic inflammatory states, and how fasting provides a hormetic stressor—mild, beneficial stress—that stimulates repair and renewal systems. This foundational change in metabolic health can put many chronic conditions "off the table," dramatically improving healthspan and quality of life.

The Hormonal Brain Rewiring of Midlife Women

A compelling part of the discussion focuses on the neurological changes accompanying menopause. Dr. Pelz explains that as estrogen and progesterone decline, the female brain undergoes a significant rewiring—shedding old neural pathways and growing new ones suited for leadership and autonomy, rather than people-pleasing or caretaking roles.

This "third brain rewiring" is part of the evolutionary "grandmother hypothesis," suggesting that post-reproductive women historically assumed roles of leadership and community support. However, modern society often fails to recognize this transition, framing menopause negatively instead of as a powerful new phase. Dr. Pelz urges a reframing of menopause not as loss but as potential, enhanced by lifestyle strategies like fasting and nutrition.

Hormone Replacement Therapy (HRT)

Hormone replacement therapy is a frequent yet contentious topic. Dr. Pelz advocates for a balanced view: HRT can be beneficial but is most effective when combined with lifestyle changes such as nutrition and fasting. She critiques the current medical approach, where HRT is often prescribed without sufficient metabolic context or lifestyle support, leading to suboptimal outcomes.

The complexity of hormone dosing, delivery methods, and individual variation means that many women experience a confusing trial-and-error process. Dr. Pelz calls for a comprehensive approach where good clinical care partners with metabolic training, empowering women to optimize both hormonal balance and overall health through an integrated strategy.

Practical Advice

For those interested in embarking on fasting, Dr. Pelz offers a roadmap focusing on momentum rather than motivation. She encourages small incremental steps such as delaying breakfast by 30 minutes initially and gradually extending fasting windows. This gentle approach helps overcome initial discomfort—like hunger or irritability—and builds habituation over days to weeks.

Breaking a fast with nutrient-dense meals that prioritize protein, fermented foods, and healthy fats is vital to maintain balance and avoid unhealthy rebounds or overeating. Importantly, she emphasizes that fasting is accessible across socioeconomic and lifestyle differences, offering a cost-free, science-backed tool that can empower diverse populations.

The Broader Cultural and Political Context

The conversation touches on systemic issues impacting health, such as deregulation of harmful chemicals and inadequate attention to environmental toxins. Dr. Pelz voices frustration over politicized narratives that obscure real threats like glyphosate exposure. She calls for clarity and advocacy to protect public health beyond simplistic dietary fads or pharmaceutical "fixes."

This broader perspective situates personal health within ecological and societal frameworks, urging listeners to consider how collective choices around food systems, environmental protections, and health policy influence individual and community well-being. Dr. Pelz advocates a holistic, nonpartisan approach grounded in science and real-world experience.