As usual, you have the two extremes here, both reeking of paranoia.
One thinks they'll shirnk if they dont' get a shake the instant they finish training; the other thinks the concept of having a meal or shake shortly after a workout is merely a plot by those EEEEEVVVVIIILLLL supplement companies, to fleece them of their dinero.
It's quite simple. If you're hungry after training, GET SOMETHING TO EAT or HAVE A PROTEIN SHAKE.
I've done this for years, since my teens. In high school, I'd be ravenous after training. So, I'd head to the cafeteria and inhale as much food as I could. There's something to the anabolic window thing, as I could (and still can) eat WAAAAAY more food shortly after training than I usually eat as a meal.
In college, I just simplified it further by having my last weight gainer shake about a half hour after training. That was usually the time it took for me to shower and hit the whirlpool or swim for a bit.