How to Fast for Better Health
Humans have been fasting for thousands of years, but modern research is just starting to unveil its power.
Our lives revolve around food. Our ancestors thought about little else, and it’s still one of the first things we think about in the mornings. We organize our social connections and our daily schedule around eating. We relish cooking shows, farmer’s markets, and the thriving gardens in our neighborhoods – they all exemplify the bounty and beauty of food in our lives.
In our culture of abundance, we can easily lose sight of the benefits of going without – of intentionally choosing not to consume. As this article will demonstrate, the benefits of fasting are plentiful and powerful – enough to make it potentially a key component of your self-care routine.
What Is Fasting?
Fasting means not eating for a certain period of time. While fasting has become popular in recent years as a health-promoting lifestyle choice, it is a practice with millennia of history, deeply rooted in several religious traditions (Kerndt et al., 1982). Ancient Greeks practiced fasting to prepare for rituals and celebrations. The Old Testament suggests that fasting is a powerful way to connect with the divine, and monks have practiced fasting for centuries. Fasting has also been utilized as a form of protest, with political prisoners often fasting during their incarceration.
In the last couple centuries, doctors and scientists began to observe and track the health benefits of fasting, especially for weight loss. In the last several decades, benefits far beyond reducing our waistlines have begun to be discovered (de Cabo & Mattson, 2019).
Fasting has profound effects on our metabolism and how our cells operate and regenerate, which can reduce hypertension, arthritis, and neurodegeneration (the breaking down of nerve cells, such as in the brain) (Longo & Mattson, 2014). Fasting also strengthens the immune system and makes our bodies more stress resilient (Longo & Mattson, 2014). Some studies have found that fasting is even as effective as the typically-prescribed drugs in treating seizure disorders and conditions such as rheumatoid arthritis (Hartman et al., 2012; Muller et al., 2001).
Through many processes, fasting helps the body stay young. It literally refreshes your cells. This means that it may be able to help with degenerative diseases like Alzheimer’s and Parkinson’s and support people in overcoming strokes (Gudden et al., 2021). While these effects are more easily seen in older adults, it is possible that fasting can help with cognitive functioning in younger adults as well (Seidler & Barrow, 2021).
One of the coolest potential applications of fasting is in fighting cancer. Cancerous cells derive their sustenance from what the host body eats, so fasting deprives the cancerous cells of the sustenance it needs to survive. This is why some doctors are now recommending that people fast while undergoing chemotherapy and other kinds of cancer treatments (Nencioni et al., 2018).
Fasting is also a well-established way to lose weight. Studies have found that people who fast, whether intermittently or for very long periods of time, lose weight (Cho et al., 2019). Since intermittent fasting in particular may be more sustainable over time than diets that focus on restricting overall calories, it is often described as one of the most effective ways to lose weight (Welton et al., 2020).
It may be intimidating to try fasting. Here are some tips for how to successfully introduce fasting into your lifestyle:
1) Start modestly. Consider starting with one sixteen-hour fast in a week. Pick a day that will be low stress, where there are few demands on your time and energy. Choose a food for breaking your fast that you will look forward to, but not one that you might be tempted to eat before the fast is done.
2) Break your fast judiciously. If you eat something carb-heavy to break your fast, your digestive system will rush to process that new source of energy, giving you a big spike and dip in your energy levels. So, break your fast with a smaller meal that includes a good source of protein, such as dairy or chicken, and ideally some fiber as well. This ensures a smoother transition into the eating window.
3) Embrace your hunger. You might not believe it when you are first starting out, but hunger doesn’t last. In this regard, it is like most sensations we have – temporary. So, expect to feel hungry – and expect that the feeling will pass. If you have a mindfulness practice, consider using it to acknowledge, but not become controlled by, your hunger.
4) Consult with your doctor. For many of us, eating regular meals is important. Or perhaps you take a morning medication that wouldn’t go down well on an empty stomach. It’s always a safe bet to talk to your doctor before trying something like fasting.
Fasting is a time-honored human tradition, with origins in spiritual traditions and abundant modern research documenting its physical health benefits. If you are not someone who has tried fasting before, it stands to benefit you in many ways.
At the same time, fasting is not for everyone. If you have, or have had, a complicated relationship with eating, move very slowly with fasting. Fasting is not sustainable, or even worth the effort, if it causes you emotional distress or discomfort.
Cho, Y., Hong, N., Kim, K., Cho, S., Lee, M., …, & Lee, B. (2019). The effectiveness of intermittent fasting to reduce body mass index and glucose metabolism: a systematic review and meta-analysis. Journal of Clinical Medicine, 8, 1645.
de Cabo, R., & Mattson, M. P. (2019). Effects of intermittent fasting on health, aging, and disease. New England Journal of Medicine, 381, 2541-2551.
Gudden, J., Arias Vasquez, A., & Bloemendaal, M. (2021). The effects of intermittent fasting on brain and cognitive function. Nutrients, 13, 3166.
Hartman, A. L., Rubenstein, J. E., & Kossoff, E. H. (2012). Intermittent fasting: a “new” historical strategy for controlling seizures? Epilepsy Research, 104, 275-279.
Kerndt, P. R., Naughton, J. L., Driscoll, C. E., & Loxterkamp, D. A. (1982). Fasting: the history, pathophysiology, and complications. The Western Journal of Medicine, 137, 379-399.
Longo, V. D., & Mattson, M. P. (2014). Fasting: molecular mechanisms and clinical applications. Cell Metabolism, 19(2), 181-192.
Muller, H., de Toledo, F. W., & Resch, K. L. (2001). Fasting followed by vegetarian diet in patients with rheumatoid arthritis: a systematic review. Scandinavian Journal of Rheumatology, 30, 1-10.
Nencioni, A., Caffa, I., Cortellino, S., & Longo, V. D. (2018). Fasting and cancer: molecular mechanisms and clinical application. Nature Reviews Cancer, 18, 707-719.
Seidler, K., & Barrow, M. (2021). Intermittent fasting and cognitive performance – targeting BDNF as potential strategy to optimize brain health. Frontiers in Neuroendocrinology, 65, 100971.
Welton, S., Minty, R., O’Driscoll, T., Willms, H., Poirier, D., Madden, S., & Kelly, L. (2020). Intermittent fasting and weight loss: systematic review. Canadian Family Physician, 66, 117-125.