I agree with the others, after losing 20 lbs it's definitely time to up the exercise.Your food intake sounds pretty good but make sure you're not snacking too much throughout the day without realizing it. Sometimes I'll snack on "just a few chips" and think it won't effect but if you add it up throughout the day it really does!
Anyways I started off with 1/2 mile then moved up to 1 mile. Now after 3 months I'm going about 3-4 miles daily, sometimes just walking, sometimes just 2 miles with some jogging,etc.
if I see my weight loss slowing down I will add another 1/2 mile or I will try to jog a little further and that seems to keep the plateau away
Lots of luck and great job with your loss so far :)
| current weight: 131.6