Man does not live on bread alone, but maybe eating bread alone sometimes will help you live longer. (Photo by Ondřej P. Vaněček )

Ash Wednesday inaugurates a season of fasting for many Christians. Nowadays those fasts vary widely; perhaps you aren’t reading this post because you are abstaining from social media for Lent. Still, the classics endure for a reason, and now scientists are exploring how cutting back on food affects our bodies. The latest study found that fasting had several health benefits including weight loss, lower blood pressure and healthier blood sugar levels. Or perhaps more precisely, a “fast-mimicking diet” provided those benefits; subjects ate normally most days but for 5 consecutive days each month they ate low-carb, low-protein foods high in unsaturated fat and totaling 700-1100 calories per day.

This study is the latest result among many which show a range of health benefits from restricting calorie intake or fasting in some fashion. It’s particularly notable for being a randomized trial in humans, rather than an observational study of humans or a randomized trial in rats or other model organisms. Consequently, these results are more likely to be representative. Still, it should be noted that the trial was relatively small (fewer than 100 subjects on the restrictive diet) and only lasted 3 months. Whether the modified diet would have long term benefits such as lower incidence of diabetes or increased longevity remains to be seen. Nevertheless, the cumulative data about fasting are encouraging. Of course, no diet is necessarily right for everyone; a physician may have further advice on what diet would be best suited for you.

Fasting is a practice in a variety of religions, so the idea will hardly be new for many. I imagine some who already practice fasting for religious reasons will be encouraged to know it has physical benefits in additional to whatever spiritual benefits they obtain from it. Indeed, not everyone draws such a distinct boundary between the two; healing the body and the spirit can be one and the same activity. And if God wishes for us to flourish, it is reasonable that the practices he ordains would be beneficial for us. At the same time, I wonder if promoting fasting primarily on its health benefits brings the focus inward to a greater degree than is appropriate. Fasting is traditionally a way to be reminded that we are not fully independent and sovereign, yet using fasting to lose weight could make it another tool by which we exert control over ourselves.

Of course, I’m not discouraging the practice of fasting. And I’m not suggesting we should ignore, doubt or abandon this research direction and the possibilities for improving health. I’m just curious how to integrate these findings with the tradition and theology of fasting. I’d love to hear your thoughts on the subject!