The Unites States continues to struggle with the negative health effects associated with increasing population obesity, a problem which has been historically difficult, if not impossible, to solve. Mobile health applications represent a potential partial solution to this problem. We examine the existing literature on the effects of mobile health applications on body weight, waist circumference, BMI, and lifestyle, examining both physical findings as well as adherence, satisfaction and cost effectiveness. The use of mobile for weight reduction looks promising, but evidence is mixed, which is not surprising given the rapidly evolving nature of the mobile application field.