A new review of past animal and human studies on intermittent fasting, published in The New England Journal of Medicine, suggests further evidence of what I’ve long feared might actually be true: Intermittent fasting, or eating only between a six- or eight-hour window each day, might lead to a longer life by improving “cellular health.”
The study’s author, Mark Mattson, a professor of neuroscience at Johns Hopkins University, has studied intermittent fasting for decades, and though most of that research has involved mice, there is also some evidence that intermittent fasting may benefit overweight people. In the new review, Mattson also points to Okinawa, a Japanese island whose inhabitants practice intermittent fasting and also, perhaps relatedly, have the highest life expectancy in the world.
There has been significant popular support for intermittent fasting, particularly among wealthy, white Silicon Valley entrepreneurs, like Jack Dorsey, who has previously described his daily 22-hour fast on Twitter. Similar restrictive dieting has been highlighted in GQ, sometimes breathlessly. Obviously, Dorsey’s version is much more severe than the patterns studied by Mattson, but in either case, practitioners acknowledge that pushing past hunger is part of it.
Though Mattson’s study provides additional support for his hypothesis, there is ample reason to be wary. There is little to no research on the long-term effects of intermittent fasting; it’s not like we now have a formula that says if you intermittently fast for X years, you’ll live Y years longer.
But my lingering question remains: Even if intermittent fasting was guaranteed to lengthen your life, would it be worth it? Even Mattson writes that the practice will “almost definitely leave participants hungry, irritable, and less able to concentrate,” though he insists these symptoms “usually pass after two weeks to a month.” I don’t know about you, but I don’t trust that usually. The study review doesn’t speak to quality of life, either. Generally speaking, I’d rather die a few years earlier if it means I can eat enough to be full, functional, and happy now.
