The threads I read about lunchboxes were always because school were putting higher standards on lunchboxes than their own school meals, and very often it was taken to extremes - eg I remember a case where a school would serve a typical meal (maybe pasta, or pizza) followed by chocolate pudding, but those with lunchboxes had a frube yoghurt taken away because it was deemed too sugary (it might well be sugary, but as part of a mainly healthy meal it’s better than the chocolate pudding and custard that the school was serving up).
My son has a very limited diet and ended up not eating at all at school for years, because well meaning lunch staff always commented on what he had to the point where he refused to eat at all until after school, not even breakfast as he was too anxious. He has an awful relationship with food, and that’s on lunch staff, even after a firm letter from the paed they carried on picking at him and drawing attention to his anxiety based eating disorder.
Too much advice around diets is plain wrong, and starts the process of yo-yo dieting, or bingeing, or a poor relationship with food. It circles around the crap eatwell plate, or change4life advice (with their known links to nestle, and their, quite frankly, awful diet advice) - and this is the problem when you allow government initiatives to lead the advice - it’s not done to help people, it’s done to benefit those in charge.
And then fucking awful people think it’s hilarious to laugh at the fat people, oh they’re so stupid, they’re so lazy, and it just exacerbates the problem, and completely ignores the societal problems that have set up 2/3 of people to be overweight or obese.