Well that's the end of the potato fast for me, as my measurements suggest I'm now losing lean muscle tissue
Day 1 - No change, stats seemed identical
Day 2 - 1.3 lbs lost, waist measurement dropped almost 1/2 inch, skinfold caliper seemed about the same, Biggly Index jumped up
Day 3 - 0.22 lbs lost, waist measurement returned as before (the half inch came back) skinfold caliper moved up about 1 mm. Biggly Index dropped down, not as low as before but heading down.
I do realize this was a very short term experiment of only 3 days but here's my conclusions:
Day 1 homeostasis kicked in, appetite kept me eating, body slowed down etc. No change.
Day 2 I was half expecting a gain, if only stored glycogen and salt water bloat but a pleasant drop in both weight and waist. The skinfold calipers confirmed it.
However I attribute much of this to a 70 minute hike through a hilly park on a semi-empty stomach. In fairness though the potatoes certainly helped dull my appetite and made the whole empty stomach thing much easier!
However day 3 was a killer. Mostly a desk-bound day, which is normal, so went for a walk in the evening, just a 20 minute stroll. Didn't feel I was eating much but I WAS eating quite regularly.
I really wasn't sure what the scales were going to say this morning...
Well they said a small drop, about 1/4 lb - but my waist measurement had gone back up again. Worse, the skinfold calipers had gone back up again.
Some of that could be bloating and calipers are hard to get a consistent reading with but the fact remains the weight loss had stalled and my measurements suggest potatoes again today would probably lead to gaining fat (if I haven't already). In the meantime I'm depriving myself of protein so it's quite possible the 1/4 lb lost was muscle tissue.
My overall conclusion for me personally is this:
I need more exercise!
For 3 days my calories never exceeded 1400, which is crazy low for a 5'9" 180+ lb man. In some way yes, more than a pound lost in 3 days IS drastic but the effects should have been more dramatic. I should have been starving hungry and losing weight on the first day, but I wasn't.
Day 1, without significant exercise, nothing changed. Day 2 with a lot of exercise my weight plunged, day 3 without much exercise, not much happened - but fat weight seems to be creeping on while lean muscle fades.
To me this suggests that while the Primal Blueprint talks of how 80% of it is diet, I think for ME, personally, my normal low-carb, hi-fat diet is probably fine, my problem is that I'm sitting at my desk nearly all day, on my comfy leather chair! All day I'm either working or surfing the net, sitting on my ass.
I need to do that "move frequently" thing.
My conclusion about the potato fast in general?
I think (boiled) potatoes are a great appetite suppressant if you're going to go for a 2 day fast.
The 'magic' as such is their ability to kill appetite at fairly low calories, while removing all other nibbly choices. For that it's great but beyond 2 or 3 days I have real concerns regarding lost protein and high insulin levels etc.
I think if you're already healthy and active and just want to lose fat weight then it should be pretty effective, though I still wouldn't recommend more than about a week. However monitor closely and if it's not really working for you, stop.
For me potatoes simply helped me do something we know works anyway - a long slow exercise session on an empty stomach. I just couldn't handle the idea of potatoes for breakfast and didn't feel overly hungry, so it worked in that sense.
In short, in CAN work, it certainly does work to some extent for most people, just monitor closely and use it as a learning tool as well as a short-term hack.
Otzi has discovered something useful, if you don't abuse it.
AC