While almost everyone can lose weight short term, 95% of weight loss attempts fail within 5 years:

“You can initially lose 5 to 10 percent of your weight on any number of diets, but then the weight comes back. We found that the majority of people regained all the weight, plus more. Sustained weight loss was found only in a small minority of participants, while complete weight regain was found in the majority. Diets do not lead to sustained weight loss or health benefits for the majority of people…In addition, the studies do not provide consistent evidence that dieting results in significant health improvements, regardless of weight change. In sum, there is little support for the notion that diets lead to lasting weight loss or health benefits.”

http://www.ncbi.nlm.nih.gov/pubmed/17469900

How many "dieting attempts" does a person need before they (the 66 billion dollar dieting industry) realize the dieter is not the one failing?

http://www.timesunion.com/business/press-releases/article/U-S-Weight-Loss-Market-Forecast-To-Hit-66-4156531.php