Im working out more and eating less and i seem to be building mass why?

Question

i eat twice a day run and lift weights and do calisthenics 3 times a week with a 2 mile hike daily and boxing every other day

Answer 1

First of all you need to eat more. eating less is really unhealthy and if you dont eat enough your body will eventually shut down and you will gain weight.  And you are building muscle not fat or anything.

Answer 2

While you are losing fat with running and hiking, you are gaining muscle because of the weight lifting, calisthenics and boxing.  

Answer 3

they're called muscle mass