No. Grappling is mostly technique and leverage. It's only about who's heavier if both are of the same skill level. If you're 150, of course you're not gonna wanna try to pick up a man who is 250 cuz that's a waste of energy, but it's definitely possible. Using a double leg, you don't even have to lift the person up because if you do it correctly, your technique/leverage alone will already have dude off his feet, all you gotta do is duck walk, scoop the legs, drive forward with your head and he's down. Besides....arts like Judo, Jiu Jitsu...etc were designed specifically for smaller people to be able to deal with larger people in close quarter combat.
