This is bad advice. You want to eat two large meals and a light one to minimize total insulin exposure. If you eat and snack all the time you keep insulin spiked up too much.
Working out six days a week to stay thin is completely ridiculous. Once or twice should be sufficient if you're eating right.
Longer fasting periods train your body to switch to running off fat reserves quickly. Metabolism does not slow.
I do agree, though, that if you're eating, say, nothing but pasta and sugar for all of your meals, your insulin will stay high. But that's because of the food you're eating, not the frequency.
Fasting periods raise growth hormone levels, snacking and insulin suppress growth hormone. You should fast an hour after lifting for this reason. If you eat immediately after lifting you shut down a large surge of growth hormone. (Bet your exercise articles didn't mention this either.)
No culture has ever done six meals a day. It's not going out on a limb to suppose we're made to eat two or three times a day.