Sounds to me like they can’t make up their minds if weight loss is good or not.
It’s my opinion that it is the actual caloric intake that is detrimental, rather than the weight gain per se. A frugal diet allows the body to metabolise in moderation, whereas excessive intake strains the metabolism. Of course, a steady frugal diet leads to a slimmer body, which is a help, but I think it is the reduced metabolism which is the principal benefit.
Mark Twain observes of Tom Sawyer’s Aunt Polly, “she was particularly devoted to her health magazine, never noticing that the good advice in this one contradicted the good advice in the previous one.”