I have a roommate who drinks fat-free milk and eats lots of salad and pasta, who avoids meat like the plague. He's been struggling with his weight for as long as I've known him. I drink coconut milk -- which contains nothing but fat -- and a meal usually consists of some randomly selected fatty cut of meat and vegetables fried in the drippings. That, or cheap canned fish. I lost weight eating like this. I fit in skinny jeans. I may with luck convince my almost-girlfriend to peg me. :3
But the important thing -- I don't advertise. I am not a walking bulletin of the health benefits of coconut and sardines. How do you really know about the diets of the people around you? I would say there are maybe four or five people around me whose diets I actually know well enough to analyze in any reasonable way.
Case A is a twenty-two year old recent Caltech graduate who is obsessed with freerunning and eats nearly-strict paleo. He can do a backflip. No further comments. We grew up together.
Case B is my roommate. He follows all the conventional advice to a T -- chicken, fish, whole grain, salad. Lots of "health food" products. Y'know, healthiest potato chips on the shelf. There is bread, there is soybean oil mayonnaise. It... doesn't seem to be working.
Case C is another good friend of mine. Eats a lot of processed cheap stuff; he's the sort that'll buy three pounds of animal crackers. When I first met him he was rather obese and said he was try'na learn to eat vegetables. He lost a lot of weight after we introduced him to ecstasy... and he's been eating healthier too. He's sloowly coming around; one of his recent facebook statuses involved making hard-boiled eggs. He looks better and seems happy. Score 281,443 for MDMA.
Case D is me. I'm kind of a dick, judging people like this. People who I like. I don't really know any other way to be honest about how I make decisions, though.
When I was eleven my parents tried to force me to switch from whole milk to 2%. I responded by walking two miles to the gas station to buy milk. I'm the only kid in my family who never had weight problems growing up.
Eyes optional.