Hello! Im an 18 year old female. I'm 5'4" and weigh 149 pounds. I'm new to MFP and i really want to lose around 20 pounds. I've been on the 1200 calorie diet and i follow it pretty well. Its been 16 days and i have lost 5 pounds. I was just wondering if i should be eating back the calories that i burn. i do 65 mins of…