There's only 3 macronutrients.

THEY want you to limit fats (and sat fat and cholesterol) to a bare minimum.

THEY also want you to limit protein to a paltry 54 g (preferably plant based of course).

The only macro left is carbs - Oh yes, eat lots of carbs, lots and lots of them! Fill up on them!

Then you can be hungry again in an hour, since you didn't have enough fat or protein to sustain you! Just carbs to skyrocket your blood sugar, followed by an inevitable blood sugar crash and lack of energy.

Then you can fill up on carbs again!

And be starving in an hour... and fill up on carbs again!

Rinse and repeat over and over, all day long, until you fall into bed utterly exhausted and weak from lack of protein and lack of sustained energy, then you can do it all over again the next day.

What a miserable roller coaster.