All of our fitness and nutrition advice is troubled by the cargo-culting, marketing-driven, personal-religion factors: if I go to a yoga class I spend a lot more time and money to get effects roughly similar to doing a high school gym class stretching regime each morning and evening. I paid $14 yesterday for the experience of a burger with a fancy name and an overly sweetened bun that was ultimately less satisfying than Burger King. If I buy and use supplements marketed by a bodybuilder, or try to follow their training program as printed in a magazine, I'm not going to look like the bodybuilder, and I will probably overtrain, because they weren't using the supplements at all, they were using a PED stack to train harder, eat more, and recover faster without overloading their system. Worrying about my body weight, BMI, or aesthetics is similarly Quixotic in that my body will prefer to stay in a certain range regardless of how I eat or train, and the numbers I can consistently improve tend to be "weight and reps" or "time and distance", while aesthetics and vanity numbers are much harder to aim towards.
To wit, it's more important to develop your own feedback loops for each of these things. There are serious concerns with fitness and nutrition in the U.S. but they aren't necessarily because it's impossible to get at the good stuff: it's just that eating beans and rice and oatmeal, making a habit of stretching and bodyweight exercise, and studiously logging one's training are all unfashionable, implicitly discouraged by most workplaces, and not well served by market forces.