<human>: Can you condense the text into three sentences or less?

Hello, this is my first post in r/running. I've read the FAQ, and I'm wondering if anyone can help me out with my running workouts. I am male, 5'11", 195 lbs (about 5-10 lbs of "extra lovin", rest is muscle) I run between 2-3 times a week, for 3-4 miles per workout. Over the past month, my pace has improved from about 9 to 8 minutes per mile. I am currently dieting, with my daily caloric intake at around 2000 calories. I live a sedentary lifestyle as a computer scientist. I run on a treadmill because of the lower impact surface than the roads outside (I've gotten shin splints many times before, and have a few lingering minor injuries from playing football in high school)

I haven't been able to run more than 4 miles because I run out of energy during my workout. Last night, I ran 3 miles in 23 mins 45 seconds. If I believe the treadmill, I am burning about 450 calories so that comes out to 18.9 calories per minute. My body doesn't seem to be able to maintain this calorie burn for an extended period. With my diet, I also don't believe that my body has this much extra energy in general for my body to burn. When I ran 4 miles (about 600 calories), I got back to my apartment and almost passed out in the shower. 

Does this sound about right? How can I improve my performance without increasing my calorie intake (if that's even possible)? Would anyone recommend specific diets or calorie intake plans to improve my runs? Thank you guys for listening!
<bot>: 24 y/o male, 195 lbs, 5'11", running 3-4 miles 2-3 times per week, how should I eat to improve my performance on 2000 calories per day?