Question

How do you lose 40 pounds in less than a month? Someone explain to me, please.

Answer 1

Exercise daily eating healthy eating smaller proportions of foods not eating so much bready foods like bread pasta and cake 

Answer 2

By knowing your daily maintenance caloric requirement and going into a deficit.

However 40 pounds in a month is too fast and unhealthy unless you're morbidly obese which is eventually going to result in loose skin and metabolic problems.

I'd start with a caloric-deficit. Water fast or intermittent fasting.

Plus if you'd like to know the exact caloric requirement; comment your age, sex, daily intake and level of exercise. 

Thanks.