I wonder how they control for that in lab monkeys. They aren’t typical, right? I guess they probably get less exercise than wild monkeys.

This article describes some of what they do with lab primates for obesity: https://www.nytimes.com/2011/02/20/health/20monkey.html

Essentially: put them in small cages for years, give them a nearly unlimited supply of food, and give them nothing to do. Terrible.