I have done very long fasts (30, 60 days) with the supervision of my excellent naturopath, mainly for colon cleansing.
I was lucky to have her input... I would see her every ten days and she would say "Go do another ten!" And off I would go! The reasons I fasted this long was to do a deep cleansing on my poor abused, badly impacted colon. That 60 day sucker did the trick!!
I did a professional
colonic every ten days, and switched from the
Master-Cleanse to fruit/veg juices on day 48--the lemonade finally let me down on day 45. The juices picked me up and I was Jette Propelle through day 60!
It is not recommended to do very long (over two weeks) fasts without supervision, and I was glad on several occasions that I had the support (nasty kidney crisis on day 18 for example--with herbal and homeopathic prescriptions I was able to fast through). As you say, metabolic changes can be intense with a longer fast. I lost hair starting two months after my 60 day fast, for about two months... my naturopath explained the changes that were taking place and that it would grow back (it did)...
When fasting unsupervised, I prefer to do a series of shorter fasts. I did 5 tens this summer, with ten days cleansing diet between, with excellent results and MUCH easier to break than a long fast!
So, bottom line, the downside of long fasting is more difficult break (the 60 day fast took me about six MONTHS to break!), and metabolic changes causing side effects like hair loss.
If you want to continue fasting, but are just plain sick of the lemonade... consider tacking a juice fast on the end of your MC. Just drink FRESH fruit juices in the am, veggies in the pm. Total juice intake should be 3-6 cups, with lots of extra water, herb teas ok... and keep your colon VERY clean every day you fast, just as you do with the MC. I make up enough juice for a day, and keep it airtight in the fridge. Feel free to substitute a plain
water enema for the SWF, which can be harsh long term. Juices are FAR more supportive than the lemonade, a good choice if you want to continue your cleanse a bit longer before breaking.
And remember, a longer fast does mean a longer break! My wonderful naturopath has me add 1 tsp. metamucil 3x daily when I start to eat, until digestion is fully reestablished.
Whatever you decide, have a wonderful cleanse!
Best,
Somer