Illustrated By Sydney Hass.
Here at R29 Wellness, we have major problems with words like "cleanse" and "fast" — particularly when they're preceded by the word "juice." Not only are crash diets like these largely ineffective, but they encourage people to adopt unhealthy attitudes and habits that tend to be based on popular myths rather than metabolic science.
With that in mind, an interesting new study published last week in the journal Cell Stem Cell has found evidence suggesting that there might be at least one significant benefit from fasting. Researchers from USC looked at the effects of "prolonged fasting cycles" — that is, no food for a period of two to four days — on both mice and human subjects. They found that fasting reduced the subjects' number of white blood cells as well as their levels of the hormone IGF-1 (high amounts of which are associated with increased cancer risk) and the enzyme PKA.
Scientists have long known that PKA needs to be shut down in order to spur the body's stem cells into action. In this case, this combination of effects from fasting resulted in a dramatic increase in the body's ability to regenerate white blood cells. In other words, the researchers found that while fasting causes the body to go into survival mode, killing off old white blood cells in order to increase efficiency, it also stimulates stem cells to rebuild the immune system from the ground up.
The study's authors note that these findings could be especially helpful in treating patients suffering from autoimmune conditions, or those whose immune systems have been damaged by chemotherapy. The researchers are also hopeful that this information might influence future clinical applications involving other body systems. However, they stress that bouts of fasting like the ones in the study should only be attempted under the direction of a physician.
Of course, many readers will note that this isn't the first time science has found benefits associated with short, controlled fasting periods. For years, alternative health experts have sung the praises of intermittent fasting, which can involve anything from extreme caloric restriction five days per month to eating only within an eight-hour window each day. And, some animal studies have shown significant health effects from certain variations of these programs.
But, as we've said before, it's important to remember how little we really know about how metabolism works; our systems are heavily influenced by genetics in ways we don't fully understand. Studies like these give little clues to what might one day become big answers — but we don't recommend giving up grub just yet.