Intermittent fasting is not very different from what we already do in Bright Line Eating. Most of us eat dinner around 6 p.m. and have breakfast at around 7 a.m. the next morning, which is 13 hours of “fasting” each and every day. If you would like to increase the duration of this intermittent fast, you can have dinner at 4 p.m. or 5 p.m. and not have breakfast until 9 a.m. This would result in a 16-17 hour fast between dinner and breakfast. I don’t know of any benefits to extending the nighttime fast, but I don’t see any harm in it, either. Intermittent fasting is not, in principle, out of alignment with what we do in Bright Line Eating.
Total fasting—consuming only water for a week, a month, or more—is possible as well, but must be medically supervised. Research shows it can be beneficial for a wide variety of ailments, diseases, and pains. If you have a condition that you would like to treat with an extended water fast, I suggest you contact the True North Health Center in Santa Rosa, CA. They offer a full medically-supervised water fasting facility, and can provide information regarding research studies on the benefits of this kind of fasting.