This Drives Cortisol Through the Roof - and We’ve Been Wrong for Decades

Cortisol and Hormonal Imbalance from Undereating

• Cortisol levels can be elevated due to undereating, even if an individual is still overweight, and this can have negative effects on hormones and overall health, with doctors sometimes misattributing high cortisol levels to excess body fat 10s.
• There is a threshold for caloric restriction, beyond which it stops being beneficial for weight loss and starts causing hormonal imbalances, and this threshold is related to energy availability, which will be discussed in more detail later 2m6s.
• When the body perceives a lack of energy, it responds by shutting down non-essential systems and elevating cortisol levels to maintain glucose and mobilize stored fuel, which is a normal survival response, but can become problematic if sustained for too long 4m42s.
• Research has shown that severe caloric restriction can lead to a significant increase in cortisol levels, with one study finding a 32% increase in cortisol levels within 48 hours in subjects who were severely calorie-deprived, and this can have a cascading effect on other hormones, including leptin and insulin 6m15s.
• The elevation of cortisol can remove the brakes on the HPA axis, which controls cortisol release, leading to runaway cortisol levels and a dominant hormonal signal that can reshape the body and hormones, and this can be triggered by repeated or prolonged caloric restriction 8m30s.

Energy Availability and Hormonal Response

• The endocrine system responds to signals such as blood glucose, liver glycogen, and insulin levels, rather than just calories, and when these signals indicate a lack of energy, the body adapts by elevating cortisol and other hormones to maintain survival, but this can come at the cost of overall health and well-being if sustained for too long 5m0s.
• When the body is under low energy availability, it prioritizes survival over reproduction, leading to a decrease in reproductive hormones such as testosterone, estrogen, and progesterone, as these processes are energy-expensive and not essential for immediate survival 10s.
• The mechanism behind this decrease in reproductive hormones is the suppression of gonadotropin-releasing hormone (GnRH) pulsatility, which is the master signal for reproduction, and when this process slows down, downstream hormones such as luteinizing hormone, follicle-stimulating hormone, testosterone, estrogen, and progesterone also decrease 1m5s.
• This suppression of reproductive hormones can occur even if an individual still has body fat, and in women, it can manifest as luteal phase defects, anovulation, or low progesterone, while in men, it can lead to decreased libido, fewer morning erections, and increased irritability 2m6s.

Mitochondrial Function and Energy Production

• Mitochondrial function is crucial for efficient fat burning, and having dysfunctional mitochondria can lead to decreased energy availability, even if an individual is consuming enough calories 3m30s.
• To improve mitochondrial function, it is recommended to increase exposure to red light and sunlight, as these can help the mitochondria produce energy, and to engage in activities that increase autophagy, such as sauna use, occasional cold exposure, and high-intensity interval training 4m40s.
• Increasing autophagy, specifically mitophagy, can help improve mitochondrial function by removing damaged or dysfunctional mitochondria, allowing for more efficient energy production 5m20s.
• High-intensity interval training, such as 10 minutes of exercise, can be more effective for mitochondrial adaptation than doing long zone 2 exercises for 30-70 minutes, and this is related to the improvement of mitochondrial function 10s.
• Urolithin A, a compound found in pomegranates, triggers mitochondrial autophagy, which is the process of breaking down old and weak mitochondria and recycling their components to create new and stronger ones, leading to improved fat loss and insulin sensitivity 42s.

Sleep and Cortisol Regulation

• Sleep is also an important aspect, and taking 3g of glycine and 400mg of magnesium before bed, as well as dimming the lights and turning off LED lights after 5:00 p.m., can help improve sleep quality and reduce cortisol levels 2m6s.
• Urolithin A can be taken regularly, even when not fasting, to induce autophagy and help rebuild mitochondria, making it a foundational compound for longevity and improved mitochondrial function 2m6s.

Metabolic Rate and Thyroid Function

• When energy availability drops, the body deliberately slows down the metabolic rate by reducing the conversion of T4 to T3, leading to a decrease in basal metabolic rate, thermogenesis, and energy levels, even if the thyroid panel looks normal 4m30s.
• This reduction in metabolic rate can make it difficult to lose weight, and it is not a result of the thyroid gland failing, but rather a deliberate response to conserve fuel, and there are ways to fix this issue and improve thyroid function 6m30s.
• Calories are just one part of the equation when it comes to weight management, and other factors such as thyroid function and cortisol levels also play a significant role, especially when undereating and stressed 10s.

Cortisol, Thyroid Suppression, and Metabolism

• Cortisol directly inhibits conversion enzymes, and when combined with undereating and stress, it can lead to thyroid suppression, resulting in a slowdown of metabolism, and this can be further exacerbated by aggressive calorie restriction, intense training, and high caffeine intake 1m5s.
• Metabolic signaling, specifically leptin and insulin, is a critical component in the regulation of fat loss and calorie reduction, and these hormones respond quickly to changes in energy availability 2m6s.
• A study published in the Journal of Sports Sciences found that exercising men under low energy availability conditions experienced a significant drop in leptin and insulin levels after just 4 days, regardless of whether the low energy availability was due to eating less or exercising more 3m15s.
• When energy availability falls below a certain threshold, leptin and insulin levels drop, triggering a scarcity signal that can lead to fat loss in the short term, but also causes cortisol levels to rise, resulting in the suppression of reproductive hormones and a slowdown of metabolism 4m30s.

Energy Availability Threshold and Health Implications

• The research suggests that the minimum energy availability floor is approximately 30 calories per kilogram of fat-free mass per day, and this can be calculated by subtracting body fat from body weight, converting the result to kilograms, and multiplying it by 30 6m40s.
• Understanding and avoiding the threshold of low energy availability is crucial to preventing the negative effects of cortisol elevation, thyroid suppression, and reproductive hormone suppression, and to achieving sustainable weight loss and overall health 8m0s.

Avoiding Endocrine Disruption and Recovery

• To avoid endocrine changes, it is essential to have at least 1,950 calories available after workout burn is subtracted, as going below this threshold can cause leptin and insulin to collapse, and the endocrine cascade to begin 10s.
• When reintroducing calories, it is recommended to do so in the absence of insulin or glucose spikes, and to increase calories from protein and healthy fats, such as olive oil, rather than carbohydrates, to avoid a reactive insulin dynamic 42s.
• Increasing metabolic rate can be achieved by dropping calories from carbohydrates and increasing calories from protein and healthy fats, and it is also important to move more and eat more, by increasing activity alongside increasing calories, which is known as GFlux 2m6s.
• It is crucial to not stack stressors, such as calorie restriction, hard training sessions, poor sleep, and high caffeine intake, as each of these can independently increase cortisol levels and decrease thyroid conversion 2m6s.
• Maintaining a moderate amount of carbohydrates, even during calorie restriction, can help reduce cortisol spikes, as the body has to manufacture its own glucose when carbs are absent, and keeping dietary fat intake sufficient is also essential for steroid hormone synthesis 2m6s.

Monitoring and Reversing Hormonal Imbalance

• Monitoring early signals of hormonal imbalance, such as changes in cycle length in women and reduced libido in men, is vital, as these can indicate suppression before blood work appears abnormal, and recovery is faster when caught early 2m6s.
• Thyroid research indicates that T3 levels can rebound quickly with refeeding, especially when carbohydrates are reintroduced after increasing calorie intake with fats and protein 10s.
• The thyroid system is highly adaptive, and recognizing its adaptability can help with faster course correction, allowing for the increase of calories via fats and protein, and activity levels, with occasional carbohydrates if going back into a calorie deficit 42s.

Calorie Restriction Thresholds and Endocrine Health

• Calorie restriction and fasting can be effective, but the endocrine system has a threshold, and staying below it for too long or hitting it too often can create an environment optimized for survival rather than performance, fat loss, or overall well-being 2m6s.
• There is a connection between cortisol, thyroid suppression, and visceral fat, which is inflammatory and problematic, and addressing this issue can be crucial for those dealing with related problems, with additional information available on how to combat visceral fat 2m6s.