It didn't take 15 years to cause a problem. There was a problem long before the problem became unbearable and she needed treatment. Likely also significant nutritional and metabolic damage along the way.
> even 1 meal of McDonald chicken nugget is bad for health
I think this isn't true in any meaningful way. Absolutely, making it (or any fast food) a big component of your diet is not going to promote good health. The more often you eat them, the more likely it will have an impact on your health, mostly from the increased sodium and trans fats. Consistently living with high blood sugar and higher LDL will increase your bad health outcomes. But in the example of the parent, it's not just the negative consequences of consuming fast food, but the negative consequences of not eating anything else (so lacking in many micronutrients).
The good news is this makes the marginal impact of one meal over your lifetime is absolutely miniscule. It's not like each meal increases your risk of mortality a linear amount.
I understand it's not fair to compare a dog to a baby but I'll just throw it out there. When my dogs refuse to eat the food I give him, I just take it back and surely enough 12 hours later he is eating the very same food he refused before. A kid isn't a dog but sometimes it got to get worst before it gets better.
About macnuggets : I might be extremist in the way I consider alimentation but I consider that even one McDonald's nuggets is bad for health not only for the immediate impact on your body, which is indeed minimal from one meal, but mostly because it gives a bad Habit.
Everyone likes junk food, it always tastes better than healthy food so you're putting yourself at disadvantage at the very first bite in a chicken nugget. A bit like what happens with drugs, the first time is the most important and the more you do after the worst it's going to be to get out of it.
Trying to enforce healthier eating on our daughter lead to her being underweight.
Her nutritionist, pediatrician, endocrinologist, and therapist all advised us it was better to allow her to eat her comfort foods rather than fight her on it.
Almost anything is fine in moderation. It’s honestly not that bad beyond the saturated fats, and even then an otherwise healthy and active person who eats other healthy things during the day would be totally fine having nuggets for dinner every day
https://www.cbsnews.com/news/british-teen-stacey-irvine-hosp...