9. Technology Assessment: Study of User Preferences for Weight Loss Mobile Applications Both Globally and in the United States

People can be classified being overweight by using the number called body mass index (BMI). BMI correlates with the amount of body fat of people, and it can be calculated by dividing weight in kilograms with height in meter squared [1]. For adults who are classified overweight have a BMI between 25 and 29.9 and those who have BMI of 30 or greater are classified obese [1]. There are many causes leading people to become overweight and obesity in the USA: for example, (1) high-fat food intake such as fast food that contains high sugar and fat is the most organized cause, (2) the absence of physical activity for energy expenditure, and (3) lack of sleep which is associated with weight gain [2, 3]. In the present, there are many adults in the USA who are classified overweight. According to the prevalence of overweight, obesity, and extreme obesity among adults: USA trends 1960–1962 through 2009–2010 report from the National Center for Health and Statistics (NCHS), it has shown that there are 33% of the US adults who are classified overweight and the average trend has remained the same without a significant decline [4]. With the large percentage of overweight adults and the increase in number of dieters from Gallup survey by 33% from 2004 to 2010, the number of dieters could be anticipated to reach 108 million with 86 million of them are trying to lose weight by themselves. With the increase of number of dieters, the total of US weight loss market is also estimated to grow 4.5% to $65 billion in 2012 which is higher than the 2% growth from the last year [5].