I just read this article about a mother being jailed for failing to take care of her 550 lbs 14 year old son. Generally I think one of the core principles of our country is individual liberty. Freedom of speech, right to privacy, etc. I'm no libertarian by a long shot (they're just corporate shills) but I am one of those progressives who would rather see 10 guilty people go free than to jail one innocent person.
Obviously we rightly jail parents for child neglect and abuse on a regular basis. Protection of children is one of the most important duties of our law enforcement system. So the question here is really, is having a 550 lbs 14 year old son child abuse? One thing to note in case you didn't read the article, she was given instructions to get her son help for his condition and did not do so. Only then was she given jail time.
To answer this I think you only need to look at the reverse side; what if the boy weighed only 75 lbs. There'd be no question malnourishment and starvation would result in jail time. Thus we obviously have a line for "too skinny" where it becomes abuse. The only question then becomes, is there a line for obesity? I think the obvious answer is yes. There is definitely a point at which your child is no longer chubby or even fat, but is so morbidly obese that the condition is no longer natural or accidental but a result of deliberate action.
They don't go into details of the son's diet in the article, but I'm sure if they did his daily calorie intake would be far in excess of the 3,000 calories per day he probably needs (at most, considering I'm guessing he's not doing any sports.) To me ignorance is no excuse in this case. Even fast food has dietary information readily available. Even if you choose to ignore it, your body gives you signs that you are eating too much as you balloon up, well before you hit 550 lbs.
We have really, really bad eating habits in this country. I'm including myself here, I've had weight issues myself. I'm 6'1 and most of my life fluctuated between 250-285lbs. I'm lower than that now as I've finally taken control of my diet and forced myself to become more active.
It's easy to point at the food companies for selling us unhealthy food, but the truth is even if you're eating the healthiest food there is you will get really fat if you eat too much of it. The current "large size" meals at most fast food chains are much more calories than most people should really be eating at a single sitting. They could demonstrate their seriousness about health by abolishing them. Back in Ye Olden Times in order to get as many fries as you get in a large fries now you had to order multiple fries. It may seem like nothing but the mental leap there is huge, and I think restoring that barrier would do a lot.
But I'm going off on a tangent; is a parent responsible when their child is morbidly obese? I say yes. Generally that kind of weight does not happen over night, it is a result of eating habits and inactivity patterns that started much earlier. Just like a parent has to teach their child good hygene and proper behavior, parents need to teach their kids what is a reasonable amount to eat and what is going to eventually kill them.
One last thing I want to address; I know some people are "pro-fat". Certainly I don't think everyone needs to be a size 5 or whatever, and as an adult you can be whatever weight you want to be. But as I pointed out earlier, just like there is a "too thin" line for kids, I think there is a "too fat" line. We as a society should treat over-feeding just like we treat under-feeding.
If you're going to tell me that 550 lbs is an acceptable weight for a 14 year old then I'm going to view you just like the pro-anorexia people and ignore you. You have every right to your opinion but I think it's lunacy.
UPDATE:
A couple commenters have mentioned medical conditions. While there are people who are obese due to medical conditions, this a very small percentage of the population. The vast majority of cases of obesity are due to way too many calories and no exercise over a long period of time.
All of what I wrote above is under the assumption that there is not an underlying medical condition that is responsible.