Long term health studies seem to indicate that fasting bouts can slow aging, reduce the risk of cancers, and reduce the risk of diabetes.You should work with your gyno on what your consumption should be. Although it would be safe to not eat at all on fast days, everyone should keep up water consumption, and eating about 600-700 calories on those days would trigger the physiologic effects you are looking for. Feasting days should probably not go over 2200 calories, according to the plan discussed in an NBC news storyhttp://www.nbcnews.com/health/diet-fitness/feast-or-famine-evidence-mounts-fasting-diets-n552596. It is helpful to track calories during the week so you can be sure the balance you have struck is reasonable. We do suggest that patients consume multivitamins, at least on the days of fasting, so you do not miss out on important micro-nutrients.
So, where do the fad juicing diets fall out in this realm of limited caloric intake?! You could use the juice day (think Master Cleanse) for your low caloric intake if you are consuming at least 600 calories. However, we caution about using the juicing cleanses for longer than a day or two during the week. Why? Doing a prolonged cleanse or fasting diet can plummet your metabolic rate, use up reserve muscle mass, and strip key nutrients (i.e. calcium) from your body. Thus the prolonged cleanses can have great short term results - big weight loss - but negative long term consequences such as slower metabolism and overall weight gain.