How much weight can I expect to lose during the challenge (if I'm very strict)? And/or how many clothing sizes can I expect to go down?
Burn more calories than you take in and the results will equal your effort. This doesn't mean that you should skip meals and attempt to live on a 'very strict diet'. You should focus your attention on a structured exercise plan, and commit to it as best you can during your 12-week challenge, and at the end you will appreciate your efforts.
As you can imagine, it's a question that has many variables.. and lots of "history" can impact on the amount of change such as...
How overweight you are? Have you been a yoyo dieter for years? Have you trained before? How much do you want the physique change (ie: beautiful muscles) -is it your priority or is your priority just to lose fat?
If you follow the plan strictly - that is eating ALL the meals with correct portion sizes and makeup (protein/carbs etc), do the workouts intensely, drink your water, do you mental homework (goals etc) ... You will get amazing results (very hard to do all of this right mind you)..
My observations of following a lot of women's challenges is that the "majority" of women that do this have between 20 and 30 pounds to lose, most of us can crack the 20lb mark even with a few hiccups on the way, but still sticking to the plan as much as possible.. most of us drop 2 dress sizes minimum and a lot 3. The "Elite" women, those that do the program without cheating in any aspects of the program are the ones that are in "contest contention", their numbers may or may not be higher or even lower in some cases, but the physique change is very different - lots of muscles all over the body, therefore their overall bodysize is much smaller..
Just remember.. a pound of weight is a pound of weight, but the space that a pound of fat takes up is 3 times that of a muscle (I think that's what Bill Phillips said)... that's why it is crucial to measure your success with the tape measure, clothes fitting better, how you feel and not what the scale says.
Cheers and all the best
ONWARDS AND UPWARDS!
© Abbott Laboratories,2013