When people first noticed I was losing so much weight, they assumed I was on Ideal Weight. After all those folks gained it back and I haven't they started asking questions. I point them to paleo/primal, but most aren't really interested. People want quick fixes and gimmicks. I have helped a few people to see that what you eat is way more important than anything.
To tell an obese person to 'just eat less' is such a cop out. I think if an obese person's first attempt at dieting was the Shangri-La Diet and they lost a bunch of weight without ever really learning how to eat healthy, it would be a huge failure. But for someone on a Primal Journey, why not give it a try. If nothing else, you'd be incorporating some healthy fats in your diet for a while. If you started gaining--quit. If you started losing--woo hoo!