Okay, time to be harsh.
Fat shaming is not the answer, shaming of any kind tends to cause other consequences, but leaving people to become obese and not try to help is both an economic and social issue.
Like it or not, pretend to be Libertarian or whatever, we are a community and there is an impact to our economy and our society. According to both the AMA and CDC roughly 1/3rd of this nation is obese with another 1/3rd being overweight.
The fact is... not opinion, not some soap box I am standing on but fact... is obesity the leading underline health issue killer in this nation today. Obesity is not listed by the AMA or CDC as the primary reason for death but both list the influence obesity has on heart disease, cancer, diabetes, strokes, heart attacks, etc. By various studies we know obesity makes one anywhere from 4x to 10x times more likely to die from what I am talking about than those who are at a more healthy weight.
And that leads me to the economics of the matter, healthcare costs that are distributed onto the rest of us. Again, like it or not, but all health insurance no matter who provides that insurance are all based on the exact same principle. Distribution of the costs of the sick onto the healthy. You may scream socialism or communism or whatever other shit some politician says to the media but the fact of the matter is over 17% of our GDP in this nation is purely healthcare related. And do not pretend for a moment that obesity matched with "mind your own business" nonsensical attitudes magically make this all better.
So where is the line, we all do unhealthy things? For that I am not sure.
But what I do know is when the AMA and CDC say north of 20% of all healthcare costs are because of obesity we need to be talking about it and we need to do something to mitigate it. I am not happy paying another 20% just so obese people can be at home, happy, and prideful about it. We had to do this before.... with over processed, filled to the brim with awful chemicals, and horrible production of cigarettes.
This time we have alternatives that could help without having to go so far as we did with cigarettes, food and exercise would do wonders for the 2/3rd of this nation that are in some way overweight and unhealthy. And yes, that impacts us all when we can show over half the nation is costing the rest of us in a plethora of ways.