[Reach]

Not lifting will cause you to lose much needed muscle for running. Cardio is a good way to lose muscle mass. If all you're doing is running, I promise that you will lose plenty. Ignoring weight training, whether using a gym or your own body weight, will lead to very painful consequences. A good example being shin splints.

You really only need muscle mass for sprinting.

Long distance runners are more efficient with smaller muscles (less energy expenditure per unit time).

so over this thanksgiving break i gained weight

oops

This is why weight lifting is awesome.

Thanksgiving food is great for building muscle haha.