Quick results equal quick return. It's not healthy to lose that much that quickly. A healthy meal plan and exercise program + dedication equal results. 40 lbs can be lost but in 2 months it is too drastic. Do not try to starve yourself or you will go into storage mode.
A healthy well balanced diet with lots of veggies and good lean protein and good healthy complex carbs will help. Remember that resistance training is just as important as cardio training (more muscle means higher metabolism means better fat burning)
You can do it but be patient...set attainable goals and every time a goal is hit make a new one to keep you motivated. Goals can be food or exercise related but need to have a time limit. I will eat 2 more servings of vegetables everyday this week. or I will go to the gym for 5 straight days or I will have only one soda instead of 3 a day.....Rememeber that any improvement is an improvement...I trained one girl who used to eat 6 chocolate bars a day...The first week she only ate 4 a day she felt great...people may still feel this a failure but she was improving...
So take some time to set some good attainable goals and go for it!
PAT