The same reason a bad person constantly talks about how they are a good person

A lot of the current health craze is related to the effects and aftermath of the covid pandemic.

Also I believe that the more people lose control of their lives and feel like society is in a downward spiral, the more they will try to hold on in the few ways that remain. What is one of those few ways: their own personal health and fitness. Not to mention that the gym is one of the only high profile “social”/shared spaces that remain, that are not just about shopping.

Some things are true simultaneously here:

• “Standard American diet” is very bad
• The protein recommendations coming out of health/fitness circles have been largely overblown, and are related to a fairly recent new marketing push

The problem with the SAD isn’t necessarily a lack of protein, although cutting out a lot of garbage food and replacing it with healthier food would in many cases increase protein intake (but not necessarily by * that *much)