# What is FatWatch? FatWatch is weight-tracking software designed for iOS (that is, for iPhone, iPad, and iPod touch). It is based on the methodology described by John Walker in his book, The Hacker's Diet. Because water makes up a significant portion of the human body, weighing yourself once a day yields very "noisy" data, and the seemingly random up and down fluctuations can be very frustrating to a person trying hard to lose weight. FatWatch solves this problem by computing a moving average of your weight measurements, producing a trend line that greatly reduces the noise. From the slope of this line, it also computes the equivalent number of food calories. If you are planning your meals, you can use this information to adjust your plans. The Hacker's Diet is available at <http://www.fourmilab.ch/hackdiet/>. # How do I install it on my iPhone, iPad, or iPod touch? You can get FatWatch one of two ways: obtain a copy of the source code and build and install it yourself using Apple's Developer Tools, or buy a copy on the App Store. The source code is available at <https://github.com/heroic-software/FatWatch>. Note that if you aren't already a member of Apple's Developer Program, you will need to become a member in order to install FatWatch onto an Apple device. FatWatch is sold on the App Store for US$4.99 or the equivalent in your local currency. # Why buy if I can get the source code for free? If you're not a software developer, you will probably find it easier to buy it on the App Store. The proceeds are used to maintain the Apple Developer Program membership ($100/year) and maintain the website www.fatwatchapp.com. If FatWatch happens to generate excess profits, they will be donated to the Free Software Foundation <https://www.fsf.org/about/>. # Is it legal to sell GPL-licensed software on the App Store? Only if certain conditions are met. Any entity distributing software under the terms of the GNU General Public License may not impose further restrictions on the user's rights. Apple, however, does just that, via the App Store Terms of Service, which a user must agree to in order to obtain software through the App Store. However, the GPL does not prohibit the copyright holder (in this case, Heroic Software Inc) to simultaneously offer the software to specific entities under a different license. Such a "dual licensing" strategy is not unusual. Basically, as copyright holder, Heroic Software Inc is granting Apple permission to distribute FatWatch under an agreement separate from the GPL. Unless you also have a separate agreement, you must abide by the terms of the GPL; you cannot distribute your own version of FatWatch through the App Store. (Source code distribution is still OK, however.) # How do I contribute? Fork the code then open a pull request! See CONTRIBUTING.txt for details. # I have more questions! Send me email: Benjamin Ragheb <ben@benzado.com>