Yes, fasting can provide a much-needed rest for the bodily systems. I prefer to do it with some non-starchy, low-calorie vegetables to provide green energy for the body.
One BIG CAVEAT: anyone with health issues like hypoglycemia, diabetics, et al. need to be very careful with fasting. Do it with medical supervision.
More generally, UNDER-eating (not necessarily fasting / skipping meals) is a proven method for longevity. I think it was Duke Univ. that's been doing the studies for decades on that factor.