I was slim before adopting an ancestral diet. Nevertheless, I cannot get away with eating SAD due to a butchered digestive system thanks to laxative abuse during my eating disordered years. However, like many, I'm fighting a steady battle with those curse'd "last five pounds" and yes, I think that a strict Paleo diet can help me achieve that goal.
However, I'm a sweets junkie (too much fruit and dark chocolate) and have yet to shed an ounce. In fact, I've actually gained a couple pounds, but I don't blame the diet, but rather poor decision making during a hideous encounter with birth control. Meh. I'll keep eating the way I do, as it makes my tummy quite pleased with me and thus it rewards me daily with healthy trips to the potty and a subsequent flat tummy.
As to converting people? Well, I was suffering on my previous diet (as anyone who knew me then knew all too well), and it hurts me to think of others in pain. I attempt not to convert them, but rather share with them what I've learned then encourage them to give their current diet a critical eye and challenge former beliefs about health -- and then make whatever changes they deem feasible to optimize their health. The change in me has been so remarkable that it lends credibility to my perspective, and many heed whatever advice that I proffer.
My mum is now gluten free and has become slimmer, happier, and healthier than ever. My sister dropped everything but legumes (but she doesn't touch soy) and white rice, and has shed about 65+ pounds. They are, simply stated, thrilled. That's why I share my diet with others: to bring them happiness, relief from chronic pain and depression, and whatever other malignancies that ail them. And, honestly? I think it's working. :)
ETA: I realize I sound very smug and self-righteous in my reply to conversion. I want to clarifty: I don't share with anyone unless they ask. And the only reason I say something is because I very sincerely, very naively believe that Paleo will help; and by telling somebody about it, it's my way of showing them I love them and care about them.