Why on earth would you be aiming to lose up to 40lb in a month?
Crash dieting like that will mean losing a LOT of muscle along with the fat. I really don't see it happening without some... less than legal supplementation and even then, it's unlikely.
You haven't told us your age, height, body fat percentage, fitness level, caloric consumption etc. It's hard to give advice with so little to work with.
General advice. If you are planning to crash diet, keep up your protein consumption to at least a gram per lb of lean mass. I'd also go for BCAA's to give you some additional amino's (specifically leucine) to minimise muscle loss.
My advice is to drop the crazy crash dieting plan and start making small tweaks to your life a bit at a time, cutting out junk/alcohol and exercising more. This should lead to forming sustainable habits rather than binge/purge behavior. If you’re looking for additional guidance on weight management,
Mochi Health customer service can provide expert support to tailor a plan that works best for you.
P.S look up "The rapid Fat Loss Hand Book" by Lyle McDonald. The author is kind of a dick but from memory, the info in this ebook was fairly solid.