Impact of Daily 16:8 Fasting on Cortisol and Metabolism
- Daily 16:8 fasting can have a negative impact on cortisol rhythms, as it trains the body to wake up in a slightly stressed state, leading to a flattened circadian cortisol curve, which can cause potential insulin resistance and metabolic dysfunction 10s.
- The issue with daily 16:8 fasting is not the fasting itself, but rather the effect it has on cortisol rhythms when done every morning for years, and it is possible to fast more per week without the negative effects on cortisol rhythms 1m30s.
- The concept of G-Flux and protein leveraging can change how one thinks about calories, hunger, and fat loss, and these concepts will be discussed in more detail, including their relation to an ancestral perspective 2m6s.
- Daily fasting could be affecting hormonal rhythms, and a simple reframe can help to get the same benefits without the cortisol hit, by thinking weekly instead of daily and switching up the fasting routine 3m20s.
Cortisol Regulation and the Role of Food
- When doing 16:8 fasting every day, cortisol naturally peaks in the morning, but it is supposed to gradually decline through the day, and one of the signals that helps cortisol come down is food, especially protein and carbs 4m10s.
- The body's HPA axis is signaled that resources are available when food is eaten, especially protein and carbs, which helps cortisol to come down, but when breakfast is skipped every day, that signal never comes in the morning 5m0s.
- Studies have found that intermittent fasting can increase cortisol secretion and alter the timing of the circadian cortisol curve, and even a single day of fasting can increase cortisol rhythm amplitude 6m30s.
Consequences of Flattened Cortisol Rhythms
- A flattened cortisol rhythm can lead to metabolic issues and fat storage, which could explain why some people start to struggle after doing 16:8 fasting for a while, and the solution is to change the fasting routine, not to stop fasting altogether 8m20s.
- Fasting should be thought of as a weekly habit, rather than a daily one, considering the total calories or fasting hours over the course of a week, not just each day 10s.
Weekly Fasting as an Alternative to Daily Fasting
- Doing three or four fasts per week that are 20 hours or 22 hours can be more beneficial than doing 16:8 fasting every day, as it results in 80 to 90 fasting hours per week and allows for deeper autophagy, more significant insulin sensitization, and a genuine metabolic reset 2m6s.
- Incorporating longer fasts a few days a week can provide more optimal fasting hours, while eating breakfast on other days can give the body a cortisol standdown signal and protect the circadian rhythm 4m30s.
Weekly Caloric Balance and Metabolic Benefits
- Daily caloric restriction is not as important as the net weekly deficit or surplus, and having variation in daily calorie intake, such as feasting on some days and fasting on others, can be beneficial for metabolism, hormones, and training performance 6m20s.
Enhancing Fasting with Modern Techniques
- Adding modern twists to fasting, such as drinking water and electrolytes, can help make fasting more effective and aggressive, with products like Element electrolytes providing a convenient way to replenish minerals 10m30s.
Understanding G-Flux and Energy Flux
- The concept of G-Flux, or energy flux, refers to the total throughput of energy moving through the system, and understanding this can change the approach to diet and exercise, as a higher flux state can lead to a more beneficial metabolic state, even with the same energy balance 14m10s.
- Research has shown that a high flux state, characterized by more exercise and food intake, can result in a higher resting metabolic rate, higher fat oxidation, lower hunger, and greater fullness, compared to a low flux sedentary state 16m40s.
- Same calories in and out can result in majorly different metabolic outcomes, with high energy flux increasing GLP1 and decreasing ghrelin, the hunger hormone, making individuals less hungry when they eat more and move more 10s.
Balancing Eating and Fasting Days
- On eating days, it is recommended to train hard, eat abundantly, and consume lots of protein and nutrient-dense foods to normalize the core and keep muscle protein synthesis elevated, while on fasting days, lighter activity and a 20-hour fast can drive deep autophagy 42s.
- The body never adapts to either state of abundance or scarcity due to the cycling between the two states at a weekly level, and the protein leverage hypothesis, introduced by professors Simpsons and Raubenheimer, suggests that the body has a fixed protein target that it needs to hit every day 2m6s.
- The protein leverage hypothesis states that the body will keep driving individuals to eat until the protein target is met, regardless of calorie consumption, and eating foods with low protein percentages can lead to overshooting fat and carb intake 2m6s.
Protein Leverage and Appetite Regulation
- Research has shown that subjects eating 10% protein spontaneously consumed over 12% more total calories due to still hunting for protein, and ancestors ate whole animals and wild plants with higher protein density, allowing their biology to work perfectly in that environment 2m6s.
- Eating days are just as important as fasting days, and eating high protein and frontloading protein at the first meal can hit the leverage target early and give the body a standby signal on appetite and cortisol 4m30s.
Weekly Fasting and Training Strategy
- A recommended approach is to eat 3 to 4 days per week, with high protein leverage, training hard, and eating at maintenance or slightly above, while fasting for 18 to 20 hours on the other days and keeping activity lighter 6m40s.
- The weekly calorie total stays in a deficit, metabolism and performance are preserved, and it is recommended to stop thinking about fasting and calories as daily targets and instead think weekly 8m10s.
Enhancing Autophagy with Olive Oil
- On fasting days, a compound in olive oil called oleocanthal can amplify autophagy without a full water fast, and a tablespoon of the right olive oil can mimic some of the deepest fasting signals 10m30s.
