I'm a WASP, and inherited ADD, low body weight and fat, and blood sugar issues from my dad (my mom, 100% British extraction, has battled her weight since she had me at 26, but only got really fat starting in her mid-40s. My dad is still pretty much a stick. Both love carbs and my dad eats a LOT). I've worried about gaining weight, not losing it. My two sisters are also very slim (5'10" 125 lbs and 5'3" 105 lbs), but their body fat isn't quite as low as mine. Paleo has helped me put on a couple pounds.
I need adequate carbs to feel my best, but too many affect my energy and sleep negatively, in a big way. Wheat is the worst. Balance is key.