Thinking about doing CKD, actually maybe only keeping the carb up to 12 hours or even one meal...with about 30 minutes of cardio after my 45 minutes of training.
I would think 15 would be no problem. You will dump 4 or five pounds of water right off the bat, then if you average a little less than 2 pounds a week you will make it no problem.
I'd be careful about limiting the duration of the carb-up too much. If you don't replenish glycogen properly your workouts are going to suffer and you're likely to lose more muscle mass than you might like.
Thinking about doing CKD, actually maybe only keeping the carb up to 12 hours or even one meal...with about 30 minutes of cardio after my 45 minutes of training.
Thyroid levels would drop to such a low amount in the first week that there would be no results w/ this type of a deficit. And, yes, it would eat up a lot of muscle tissue.
Personally, I lost about 20lbs doing a CKD from Feb 17 to May 1.
It's been my experience that going slower results in much less/no muscle loss. That's just what works for me though.
20lbs of fat = probably not. but i think he was just asking about 15-20lbs of general weight, as someone else pointed out, 5lbs will likely be from water.
Any deficit that is under 10-20% of your BMR (80-90% of BMR), if done naturally, will cause catabolism (muscle loss) and possible thyroid and starvation complications. It's not as easy as people think; anyone can throw out calculations (as I did of course) but for the person they are putting their health on the like; thus I suggest this process is taken slow and not rushed to the extreme.