You have to be very careful with the caloric deficit idea. On paper it looks good but there are some issues.
Now I am no doctor by any means so only take my advice with a grain of salt and this is what has worked for me. (Note: As of today - since Oct 14 - I have lost 80lbs)
Figure your BMR, just google BMR calculator. This will give you a number, right now for me (250# 6'1" male) is 2278 calories. That means that if I do nothing but breath I will burn that many calories. Your caloric deficit should be based on that number alone!
Now if you exercise that 2278 number will go up and on paper that means that your # of calories you can eat will go up but if you are serious about losing weight focus less on exercise and more on nutrition. And DO NOT EAT BACK YOUR EXERCISE CALORIES.
I eat about 600-700 below my BMR and walk about 2 miles a day.
I track my food on MFP and track my exercise with Fitbit. Fitbit caloric deficit is based on BMR plus exercise.... and not BMR alone
Long story short, eat below your BMR (alone) and you will lose weight.
now for the negative side.... if you do no exercising at all and you eat too far below your BMR your metabolism will slow resulting in weight gain if you increase your calories at all, so I stress do not stop exercising, but make your main point of focus for weight loss to be nutrition.
I am sure there are other ways to accoplish weight loss and I am sure many will disagree but I am down 80 and still making progress each week at about 3-4lbs a week!
Just saying!
K9
