Nahh, you dont need carbs to fuel your workouts. And its not leangains, its ketogains. Also leangains, the dude does not carb load before workouts, he just does some BCAA before the workout and then eats after. But yes, on the workout days, he does consume more carbs.
As for the Keto, Im just hearing all sorts of good shit about it and just basically cutting out all the shitty carbs from my diet altogether. Not from just nutritionists, but all sorts of doctors which are finally dispelling the entire myth of fat=bad, carbs=good that was fed to us since the late 70s. They cut all the fat from food and replaced it with sugar to make it paletable. 80% of the food in the grocery stores now have sugar added to them.