The problem is, the cause of obesity isn't as simple as "eating too much" as many people here are saying.
http://www.alcat.com/assets/File/Food%20Intolerance%20Causes%20Obesity%20and%20-%20Premature%20Aging%20The%20Townsend%20Letter%20-%20Roger%20Deutsch.pdf
There's evidence that food intolerance is a significant contribute to obesity. Many of the artificial ingredients used commonly in food today can cause a variety of problems which lead to poor health and obesity. And it's not like people can just not eat the artificial stuff, but the problem is, it's fucking everywhere, and there's tons of misinformation on what's good for you and what's not. And it doesn't help that the stuff that's actually healthier for you costs more then the cheap, artificial stuff.
There's also significant evidence that malnutrition contributes to obesity:
http://www.sciencedaily.com/releases/2005/08/050805111232.htm
Yes, malnutrition is actually a big problem in developed countries. Our general diet has shifted from a healthy, nutritious one to one high in fat and sugar and large quantities of food. From the article:
"An increase in availability of more high-fat and sugar-laden foods has led to a surge of nutrition-related chronic diseases around the world. At the same time that diets have changed, physical activity has decreased. The highest rates of overweight and obesity are now often found in low-income groups. Many populations have been left in the midst of an obesity crisis that exists with food insecurity and under-nutrition."
The problem is, many people that don't have much money can't afford healthy food. Shitty, unhealthy food is cheaper and more available then healthy food.
"In a separate article published in the May 2005 American Journal of Clinical Nutrition, Kennedy and co-author Linda Meyers, PhD, Director of the Food and Nutrition Board, Institute of Medicine, note that large parts of the developing world are plagued with micronutrient deficiencies. "Deficiencies of micronutrients, such as iron, iodine, zinc and vitamin A, contribute to 'hidden hunger' and while the statistics on micronutrient status for women in developing countries are scarce," she says, "it is clear that a large percentage of women from developing countries suffer negative health and nutrition consequences."
I'm not saying personal responsibility isn't a problem either, because it is, but there are other factors that a lot of people can't control as easily, especially with all the false nutritional information and fad diets that are constantly being shoved down our throats as how to lose weight and be healthy. It's not just the fault of people being lazy, it's also the fault of food producers and the government.