Pertinacity is a calorie counting iPhone app. It replaces a calorie database with a simple calorie proxy and presents an attractive interface for tracking and limiting consumption. The app requires no sign-on or setup, further simplifying use. The goal is to make daily use of the app so trivial that users keep counting calories indefinitely and create a lasting impact on their weight
Research shows that calorie reduction is the main driver of weight loss -- irrespective of calorie type -- and that calorie reduction has a greater impact on weight loss than increased exercise. Pertinacity, thus, focuses on calorie reduction.
Research also shows
(i) a strong correlation between adherence -- actually executing a weight loss plan -- and success
(ii) improved adherence with improved ease-of-use of a calorie counting system (i.e., comparing pen & paper to a weight loss app).
Based on this, Pertinacity simplifies calorie counting aiming to improve adherence.
Data collected specifically on Pertinacity's calorie proxy suggest that
(i) users can produce meaningful measurements from Pertinacity's proxy instructions
(ii) the loss of precision due to the use of a proxy is not large enough to cause an adverse effect on the user's diet.
The algorithm inside Pertinacity encourages the user to slowly, steadily decrease calorie intake. The algorithm changes the daily calorie limit over time adapting to the user's current lifestyle including activity level, set of foods from which their diet is composed, and changes in physiology.
Pertinacity is supported by www.pertinacity.org and is available as a free download from the Apple App Store