Coffee is my addiction.
Here is a link to the organization that funded the study.
https://www.coffeeandscience.org/
Lots of good information at the link.
Association between coffee intake and skeletal muscle mass among U.S. adults: a population-based study
Frontiers in Nutrition
Conclusions:
In general, consumption of coffee and caffeine is positively associated with skeletal muscle mass. Therefore, an appropriate increase in coffee and caffeine intake may be advocated in populations at high risk for low skeletal muscle mass.