How can I lose 3-4 pounds every week without exercise and diet pills?

I want to lose anywhere from 40-60 pounds in 5 months. I just started my diet two days ago and been doing so good so far I've been drinking 8 glasses of water a day, no salt, no sugar, broiled fish/chicken, oatmeal special k cereal, whole grains, fruit, veggies etc.. I won't to lose 3-4 pounds a week if possible but since it's cold out I haven't exercised and without out diet pills. Please let me know what I can do to lose 3 or 4 pounds a week and to stay on my diet this time.