And lately, not building too much muscle. Is it my diet? I've been balancing out the content pretty well (I think), and Im' sure I haven't been low on protein, but I've been spontaneously falling asleep for up to 13 hours on a regular basis Is it my diet? I've been keeping it around 1600-1800 calories. I'm 5'5 and weigh 145 right now. (bolded for skimmers) Been weight training and using this calorie limit for the past 9 months or so. Managed to lose 50 lbs, and gain a good bit of muscle in the process (not sure how much fat I actually lost). Tonight I was feeling extremely exhausted again, and I had a big calorific meal of pasta, meat, and home-made potato crisps, and 20 minutes later I feel up and energetic as ever.