While science is struggling to figure out the exact cause of the modern obesity epidemic, the theories from others continue to pile up. Among the most popular of recent opinions for why people are bigger now than they have ever been: fast food restaurants, increased soda consumption and our overall daily diet. But, according to study after study, those answers are not complete, not telling the entire story.

According to the Centers for Disease Control, 66% of American adults are either overweight or obese, with 33% of those being women. But, while this explosion in excess weight did not happen overnight, the exact start of the scale tipping point is yet another issue that cannot be agreed upon. What can be agreed on however is the fact that most of the theories offered so far have not held water at all.

Dr. Barry Glassner, a Sociology Professor at the University of Southern California is one of the first to point out that while there may be more fast food restaurants these days, it was not that they were not there in the previous generations as well. In 1966, over two billion burgers had been sold at McDonald’s, according to the signs on the Golden Arches, but Americans were relatively thin at that time. And, Glassner also reminds everyone that the average meal of the 1960’s included whole milk and typically ended with pie or cake for dessert.

If diet is not the cause, then there might be a lacking in physical exercise according to other studies. The average person spends much less time on their feet, even when they are at work. When the federal government offered an exercise guideline for the first time, it was for half an hour, but according to the experts, that half hour is not enough to cause any real weight loss even with a greatly reduced calorie diet. In 2005, the guideline was changed to 60-90 minutes of exercise but that number was not one that would work in most busy lifestyles. In addition, according to the experts, most people are very confused about what counts as exercise and what does not. A twenty minute walk at a gentle pace, for instance, only burns roughly one hundred calories.  Most people overestimate how much they are burning through movement while they underestimate how much they are eating.

As if all of this was not enough, scientists are working on proving the theory that the body has a set weight that it is born with, one that can have a range of thirty pounds heavier or lighter than the perfect number. People who are trying to force their body below this set weight amount may find themselves feeling overwhelmingly hungry and may eat more than they intend while their metabolism slows down until the weight is back to where it is meant to be. People who are overeating and getting close to being over that set point may find themselves with no appetite at all but a skyrocketing metabolism.