I don't think it's quite this simple.
To build compliance, you need to make a dopamine feedback loop.
Set small achievable goal>follow that plan>reap rewards of following that plan>set a higher goal.
Some people can just up and make changes. I know a few folks like this who just looked in the mirror and dropped >100lbs like it was nothing. I'm envious of these people.
A wife can mess up a cut/diet by making your favorite (typically unhealthy) foods and trying to coerce you into eating them when your compliance levels are lacking. This happens more frequently than you think. The fault is on the man for caving to this, but had the wife not been a lazy, conniving, mate-guarding turd - this wouldn't have happened either.
The solution cannot always be "men just need to do more, no matter what women do". Women do have agency (when they want to).
You are responsible for what you put into your mouth. PERIOD. Fvck whatever else someone makes, brings home, leaves laying on the counter, etc.
Short of them holding you down and shoving it down your throat, it's just another bullsh!t excuse people want to use. You can make excuses or you can get results. Never both.
My kids have junk food laying around the house that I could be eating. Cookies, candy, chips, pretzels, etc.
I don't. Why? Because I value hitting my goals more than eating those foods.
The only time a person goes "all-in" on this type of thing is when they reach a point where they look in the mirror one day and tell themselves it's unacceptable to look this way and is to the point they want to do something about it more than make excuses to not. Some people don't reach that point, and others take longer to get there.
But once you do, there is no turning back and you are completely dedicated to the cause and none of the stuff you bring up would phase them.