Comment by tgb

Sadly, muscle only burns 12.6 kcal / kg /day at rest [1]. If you put on an impressive 20kg of muscle that would only increase total expenditure by 250 kcal a day. If you want your muscles to burn calories, you'd better be exercising them.

[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2980962/