Nothing she's selling is a big secret. It's been known for years (meaning "scientifically" known, backed up by studies) that a sedentary lifestyle that includes long periods of sitting does a number on your metabolism, glucose, insulin, etc. If her message is "hey slob! Stop sitting around all the time," the health industry has been telling us that for a long timeTo me, it looks like the big secret (without all the privileged “hunter-gatherer lifestyle” bullshit) is “do some stretching/yoga every day”. Which any physical therapist would tell you. And can be done in modified forms at your desk/workstation. And there’s tons of free resources to get you started. (There, I saved you $19.95.)
