That sounds more like a personal problem than a statement about longevity. I doubt anyone will argue that the Okinawans enjoy a long life, and regardless of their diet otherwise, sweet potatoes remain a large part of it. Sucks that you explode them out your ass as such, but perhaps you have a really weak system?.
Perhaps I am not designed to eat such food. I'm made of largely Northern European, Native American, Irish - all big game eaters. Not tropical fruit junkies. High-protein, high-fat, low carb helps my asperger's anyway. I have no reason to try to reprogram my digestion back to carbs after all this work I've done upregulating all my fat metabolism pathways. I mean, I've been fine tuning this machine for three years. Not changing the fuel mixture now. I'm happily a fat-burning beast who eats more meat than you, and I'm feeling amazing for it. YMMV.
But i agree about leaves. Pointless. When you say fatty or colorful ones, can you provide examples of which ones you mean?