Hey Team,
Fasting is a practice that’s been around for thousands of years and originated in religious practices. In these traditions, fasting wasn’t primarily about physical health, but rather spiritual elevation and purification. At the time many participants did acknowledge the bodily benefits of both rest and restraint, which serves as the main catalyst of today’s surge and interest in fasting culture. Though today fasting has become just as complicated as most things in our society, and there are both naysayers and nonbelievers, and those that honor it daily, weekly, or monthly.
One question remains; does it work? The answer? It depends. While fasting can be a powerful tool for cellular rejuvenation and metabolic balance, it also has potential downsides that shouldn’t be ignored. Today we’re breaking down the myths, the evidence, and what makes fasting right, or wrong (!), for different people. Let’s get into it.
The Science of Cellular Cleansing
Fasting activates autophagy, a natural biological process where cells clean out damaged components. This is essentially your body’s built-in renewal mechanism, and it's been associated with everything from reduced inflammation to improved organ health and longevity. Groundbreaking work in this area helped earn a Nobel Prize in 2016, and further studies have shown fasting's potential for cancer prevention and cellular repair.
In animal models, a single 24-hour fast has been shown to enhance intestinal stem cell regeneration and improve immune responsiveness. However, researchers also caution that during the refeeding period following a fast, stem cells shift rapidly into high-growth mode, which may pose its own risks if not monitored carefully. In humans, science is still evolving, but the benefits of moderate fasting for cellular health are becoming increasingly well supported.
A word to the wise — fasting isn’t universally beneficial. For some people, particularly women or individuals with low body fat, fasting can disrupt reproductive hormones like DHEA or testosterone. Some studies have shown that time-restricted eating in women with higher BMIs leads to temporary drops in DHEA, while in lean men, prolonged fasting can reduce testosterone levels. For others, fasting might elevate stress hormones or lead to fatigue, dizziness, or even disordered eating habits if approached rigidly.
Metabolically, fasting can have wide-ranging effects on hormones like leptin, ghrelin, insulin, and cortisol. These changes aren’t inherently good or bad, but they can produce very different results depending on a person’s age, sex, baseline health, and activity level. This is why we always emphasize context.
Not All Fasts Are Equal
Intermittent fasting (like 16:8 protocols) is the most common and generally easiest to maintain. It offers metabolic benefits and promotes mild autophagy without requiring extreme caloric restriction. This is where most people start and often stay.
A full 24-hour fast, performed once a week or a few times per month digs deeper. Research in both mice and humans suggests this can increase stem cell function and boost resilience in the immune and gastrointestinal systems. However, it must be done carefully and with a strong understanding of post-fast nutrition.
Then there’s the 72-hour (or longer) fast... a rising trend popular among biohackers and longevity enthusiasts. These extended fasts have shown dramatic effects on reducing insulin levels, increasing ketone production, and potentially regenerating immune cells.
Still, the research is limited, and long fasts should never be done casually or frequently without supervision, especially for people with underlying medical conditions.
Fasting can support cell renewal, clear metabolic waste, and offer a valuable reset for the body. But it's not a cure-all, and it’s not for everyone. For some, it’s a powerful tool. For others, it may be counterproductive or even harmful. The key is understanding your unique physiology, starting slowly, and listening to your body’s signals, not following a trend blindly.
How to Get Started with
Intermittent Fasting
If you're new to intermittent fasting, the goal isn't to jump into extreme restrictions, it's to build a rhythm that works with your life and supports your health. Start by narrowing your eating window slowly. Many feel best with something like a midday to early evening window. The key is to be consistent and patient with your body.
- Hydration is essential. Since you're skipping meals, you’re also missing some of the fluid that comes with food. Sip water throughout the day, and if you drink coffee or tea, stick to plain versions during the fast.
- When it's time to eat, ease in. Your first meal should be nourishing, with a balance of protein, healthy fats, and fiber, rather than something heavy or ultra-processed.
- Listen closely to how your body responds. Headaches, fatigue, or poor sleep are signs to adjust. And if you menstruate, are under high stress, or have a history of hormonal imbalance, consider gentler fasting patterns or taking days off.
- Fasting isn’t about eating less, it’s about eating more intentionally. Prioritize real food during your eating window, and avoid under-eating, which can backfire by increasing stress hormones or slowing your metabolism.
Sleep, stress, and lifestyle matter just as much as timing. A consistent bedtime, movement, and supportive routines will make fasting more effective and sustainable. Ultimately, intermittent fasting is a tool, not a rule. The best approach is one that supports your energy, mood, and health long term.
Until next time. 👋
