I've seen that research. The sample size is way too low to make any reasonable conclusions.
If avoiding certain foods make you feel better, though, I don't see the harm in supporting that choice. Like, I'm not a big fan of soda any more, so I generally don't drink it. And adopting a gluten-free diet will probably help a lot of people kick their high-carb-eating ways in favor of less-processed, fresher food, which will likely cause some weight loss.
What gets my goat is when people try to foist a lifestyle on me that, in their opinion, is "healthier" and "better." Like, get out of my fucking face with that shit, I like soy sauce.