I have my diet pretty dialed in, but I also pay attention to when my body needs a change. Many people adjust food and experiment with recipes. I play with biochemistry. In short, if I can eat or do something that’s going to improve immunity, reduce inflammation or improve mitochondrial function, then I’m going to give it a go. Well, recently I’ve become interested in cellular degradation. It’s the state where cells become worn out and dysfunctional. And as we all know, too many faulty parts encourages metabolic dysfunction and cancerous growths thereby decreasing longevity. So, here's my question. “What’s the best way to clear away bad or damaged cells?”
Impact of Circadian Rhythms and Fasting on Health
First, a little context. Research has shown that when adults consume meals of exactly the same macro nutrient content and caloric amount, glucose levels are lowest after breakfast and highest after dinner…even though meals are 100% identical. This suggests that metabolism changes throughout the day. Similarly, we also know that metabolism is guided by an internal clock making it more active during the day for eating, exercising and working and less active at night for recovery. Now, while the external cue of light/dark helps set our brain’s active/rest states, there is another on/off switch…namely food. Food, in fact, is the oscillator that governs the circadian rhythm of the liver and peripheral tissues and regulates the body’s protein synthesis and protein break-down programs. In short, when you eat food, the body’s resources are mobilized to digest and absorb nutrients. Whereas when you go without food for a period of time (aka fasting), the body switches to a natural cleansing process to rid itself of dysfunctional and damaged cells.
Out With the Old…In With the New
While fasting is a common method for reducing calorie intake to lose weight [1, 2], Dr. Rhonda Patrick (biochemist and scientist) says, its real benefits lie in its ability to ‘clean house’ and make room for new cell and tissue growth. She says, “When a cell is damaged, it can die, but if it doesn't die, sometimes it becomes what's called senescent, and this happens a lot with aging. What that means is that the cell is not dead, but it's not really alive either. t's not doing its function. It's just kind of sitting around in your body secreting pro-inflammatory molecules, things that are damaging other nearby cells thereby accelerating the aging process because inflammation drives aging in so many different ways. Autophagy clears away those cells that are just sitting there creating damage and not doing much else, which is nice because that's also a very important biological mechanism for staying healthy." Besides triggering autophagy, fasting also:
Fasting Schedules…Eeny, Meeny, Miney, Moe
First, it’s important to note if you suffer from insulin dysregulation, chronic hypothalamus-pituitary-adrenal disruption, thyroid disorders, anxiety, are pregnant or breast-feeding, you probably shouldn’t fast. Having said that, here are three popular fasting schedules.
Best Practices for Implementation
According to Dr. Patrick, regardless of your actual age, how old you look corresponds with key biological biomarkers (e.g., telomere length, DNA damage, cholesterol LDL, glucose metabolism and insulin sensitivity), which are all largely driven by the health of the mitochondria. Yes, eating the right nutrients and exercise are important for promoting mitochondrial health, but fasting is the mechanism that triggers the body to rid itself of unwanted cargo. Hence, she advocates the following:
Now, I also asked my friend, advanced functional medicine practitioner and nutritionist Tom Malterre for his opinion. He says of course the body needs periods of rest and non-eating, but he’s not convinced that it needs to be programmed. He says the body is ingenious…constantly triaging itself, sending and creating nutrients when and where it needs them, as well as ridding itself of toxins and dysfunctional cells. Because metabolism, digestive enzyme, hormone and neurotransmitter production all go down with age, however, he recommends adults experiment with meal size and timing to make sure they're allowing the body the best opportunities to utilize fuel. For example, many of his clients eat their biggest meal at breakfast and don't eat 3 hours before bedtime. He says although some of those things may be considered a form of time-restricted eating, his motivation is to help people align food intake with their body’s digestion and absorption capacities…so fuel is available when it’s needed.
Bottom line, while fasting likely encourages the body’s cleansing and cellular regeneration processes (aka autophagy), it’s probably not the only mechanism. If it speaks to you, then give it try, but make sure you focus on eating the food that works for your body. That’s the most important thing to consider for optimizing cognitive and physical performance with a youthful vibrancy throughout life.
 Hatori, M., Vollmers, C., Zarrinpar, A., DiTacchio, L., Bushong, E.A., Gill, S., Leblanc, M., Chaix, A., Joens, M., Fitzpatrick, J.A., et al. (2012). Time-restricted feeding without reducing caloric intake prevents metabolic diseases in mice fed a high-fat diet. Cell Metab. 15, 848–860.
 Heilbronn, L.K., Smith, S.R., Martin, C.K., Anton, S.D., and Ravussin, E. (2005). Alternate-day fasting in nonobese subjects: effects on body weight, body composition, and energy metabolism. Am. J. Clin. Nutr. 81, 69–73.
 Wu, S. (June, 2014). Fasting triggers stem cell regeneration of damaged, old immune system. USC News.
 Marinac, C.R., Natarajan, L., Sears, D.D., Gallo, L.C., Hartman, S.J., Arredondo, E., and Patterson, R.E. (2015a). Prolonged nightly fasting and breast cancer risk: findings from NHANES (2009-2010). Cancer Epidemiology. Biomarkers Prev. 24, 783–789.
 Marinac, C.R., Sears, D.D., Natarajan, L., Gallo, L.C., Breen, C.I., and Patterson, R.E. (2015b). Frequency and circadian timing of eating may influence biomarkers of inflammation and insulin resistance associated with breast cancer risk. PLoS ONE 10, e0136240.
6] Brandhorst, S., Cheng, C. W., Childress, P., Choi, I.Y., Cohen, P., Conti, P. S., Di Biase, S., Dorff, T. B., Dubeau, L., Groshen, S., Ikeng, Y., Ji, L., Kennedy, B. K., Longo, V. D., Mirisola, M., Mirzael, H., Morgan, T. E., Navarrete, G., Odetti, P., Park, R., Penna, F., Perin, L., Sedrakyan, S., Vinciquerra, M., Wei, M., Yap, L. P. (June, 2015). A periodic diet that mimics fasting promotes multi-system regeneration, enhanced cognitive performance and health span. Cell Metabolism.