The United States is the second most obese industrialized country in the world. A 2013 report stated that 31.8% of Americans were obese, compared to 14% in the mid-1970s. Obesity accounts for 10% of deaths and healthcare spending in the United States.
Proponents contend that obesity is a disease because it meets the definition of disease; it decreases life expectancy and impairs the normal functioning of the body; and it can be caused by genetic factors.
Opponents contend that obesity is not a disease because it is a preventable risk factor for other diseases; is the result of eating too much; and is caused by exercising too little

It depends on the definition you want to use.  I believe people who are obese have other things happening, like disorders like ADHD or Obsessive Compulsive disorder that drives their decision making functions.  That way they find solace and comfort in food to the point that they eat and overeat food to the point it becomes a problem.

Obesity isn't a disease so much as it's a result of other problems, diseases or disorders.

Not really. It can be the case that other things it off (such as those mentioned by warmaker, as well as others like chronic depression).
And for others its really a lack of control.
I do think that there is certainly difficulty for many in dropping weight, but they shouldn't look for a sympathy vote.
If they want to lose weight, they have that power. And their are people ready to help.
I think society is beginning to moly coddle fat people, especially with big is beautiful.
Being a little over weight is not an issue.
Being obese is, full stop.
I'm not condoning picking on people for it, but don't go the opposite way either.
A lot of the conditions that society defines, are, in my mind, purely self invention.

No, I don't think that it is. I think that is a problem, yeah, but not a disease. If I had to classify it as something, I would probably have to say I would classify it as a disorder, or a condition, but not a disease. 

"A disease is a particular abnormal, pathological condition that affects part or all of an organism. It is often construed as amedical condition associated with specific symptoms and signs." 

Source: http://en.wikipedia.org/wiki/Disease but many other sources give the same definition such as my AP Bio teacher in high school.

So with that said, YES, OBESITY IS A DISEASE thanks to the broad definition of the word disease. But I digress. Let's not be so literal for a moment because the word disease is used in a such a general sense. Let's break it down piece by piece so we can see why obesity is worthy enough to be a disease even without such a broad definition for that word.

What is obesity? tl;dr version's answer is basically when you are beyond overweight based on your BMI (Body Mass Index). This is a disease because it is bad. Yes I said it is a disease because it is simply bad. If it is not bad to be obese then nobody would care but since it is harmful it is a disease. Why is it bad? Besides the fact that being obese will screw with my sexiness and ruin my chances of survival when being chased by zombies, being obese can lead to, but is not limited to the following: Cancers, diabetes, heart disease, gout, blindness, etc...and eventually death. This makes it a disease because you can have 1st world problems like getting your blanket/cord stuck in between your chair's rolling wheel as you are reading this but that is a problem, not a disease. 

A disease is harmful, constantly to your being until it goes away. That makes obesity a disease in my definition as well as the official definition. The only problem is, no one really cares about the official definition and decides to make up their own stuff which is normal. I just did it but in the end it just supported the original definition anyways. The definition is official for a reason even if it can be vague and written in a broad, general sense. All I did was give reasons why. Obesity is a disease but some people do not label it that because 'heart disease' can be caused by obesity therefore heart disease is a disease because it is caused by being obese. Then people ignore the fact that hey wait a second, all these other diseases are actually caused by these XYZ diseases! Obesity is a disease and the complications it can cause are also diseases just like smoking is a disease that can cause ocular impairments which are also diseases. 

As for my personal take on obesity, I think it is much too harmful to our society. Even if you have 5 kids and a mentally ill brother to take care of, you can beat the stress or whatever reasons you may have of being obese. Obesity is beyond overweight as shown on the BMI scale of many countries. Some people mistakenly qualify overweight people as obese; this is obviously bad. To get to the point of obesity you need to be more than fat, you need to be really fat and geez it takes more than eating McDonalds everyday for lunch to get that far. If you tell your kids to eat their veggies then you should too. If you tell your kids to not eat this and not eat that because it is bad for you or because it will stunt your growth or whatever it is, then you should too. People who are mature enough to think for themselves should know to not let themselves get to such a point because it places a burden on you and others. Parents who allow their kids to become obese? These are horrible parents. Needless to say, like most people, I have a strong negative stance on this subject and everyone who is obese should try to find a way to live a more healthy lifestyle for themselves and for their loved ones and oh yea, so taxpayers don't have to pay for some of their services. 

Stay critical,
TitaniumOxide

Obesity is a disease. A disease that only you can cure. It causes your body to function more slowly, and will destroy your health. Obesity is caused by absorbing to much a substance that we call food. Like some bacteria, it can be beneficial to you in the right amounts. Only you can stop the disease and kick it in the rear, saying "You will not rule my life!"

This thread currently looks like it's an argument over word semantics.

I think the issue is much deeper.

If categorized as a disease, that might influence the way it's treated by doctors.

Or how it's viewed by insurance companies.

So what I'm saying is so far we're basically arguing over nothing.

We're currently arguing over whether obesity is one word or another based on definitions.

The controversy behind this is much deeper.

We need to be asking:

1. What would be the implications of obesity being categorized as a disease? (since it's currently not, to my knowledge)
2. Do those implications cause us to support obesity being treated as a disease?

Yup. Semantics.
Is obesity as disease? Is ADHD a disease? Is depression a disease? Calling it a disease just makes it easier to avoid doing anything about it other than popping a pill, when it's honestly just a symptom of a greater problem.
Though... I don't know if ADHD is just a symptom of a greater prob....