I have two regression models.
lm(TEE ~ weight + gender)
lm(TEE ~ BMR)
How do I compare these two models and check which one predicts TEE best?
Answering which model is "best" isn't very straightforward unfortunately, but here are a few metrics one can look at:
I'm also assuming the underlying relationship is linear in this case and that BLUE properties are verified for both models prior to this apples to apple comparison.
You could compare non-nested models by Davidson-Mackinnon test, it is implemented as jtest in lmtest package (http://www.inside-r.org/packages/cran/lmtest/docs/jtest)