Excessive weight is a significant problem, particularly in western societies and in the United States most of all. The numbers may vary, but general estimates are that two-thirds of people in the United States are overweight, and one-third of people in the United States are obese, or extremely overweight. Given the exceptional levels of people carrying excess weight, it's worthwhile to consider what some of the possible reasons for the overweight epidemic are.

In most cases, excess weight is a reflection of calorie consumption. There are exceptions to this, most notably in circumstances where some form of bloating illness has set in. Generally speaking however, excess body weight is directly attributed to food consumed. The formula isn't quite so simple as eating and gaining weight: it comes down to intaking more calories than get burned away by being physically active. Eating more food than is used for energy, in other words.

So then there are two factors in typical weight gain: food eaten and energy burned, or not burned. If energy goes unburned, it eventually gets stored as fat. A typical form of human energy is physical movement. Most humans to one degree or another physically manipulate their bodies. Performing this sort of physical manipulation takes energy. The level of energy required to physically move depends upon how much movement is actually undertaken. In western societies, the US in particular, people move around very little compared with how much food they take in. What we have then are lots of people who consume more energy than they use.

The X-factor of energy in the overweight discussion can be described as exercise; or more accurately, in terms of lack of exercise. This is the next factor in the explanation of levels of overweight. In short, people who are fat typically don't exercise. Overweight people do move about typically, but ordinarily moving about is not exercising. To exercise essentially means to exert physical energy at unusual levels. Under this description, walking to the car or moving down the aisle at the grocery store would not constitute exercise.

The next obvious question would be why don't people exercise. The obvious answer is that people don't exercise because they don't want to. A secondary reason, however, and one that likely carries a lot of legitimacy is that people don't exercise because they have little spare time in comparison to the amount of obligations they have. A working person who has children can see literally all of their time filled. But there are always priorities to be made, and not making exercise a priority is a good bet to lead to overweight, and all of the problems that go along with it.