FatOK also shows the caloric intake estimates to maintain and change your body fat percentage , , , . It is handy because these estimates depend on your weight.
Body Mass Index "thickness or thinness" estimate are shown in Weight entry as well as in Body Mass Index entry of FatOk, after you entered the weight and pressed Add.
All other fitness estimates are shown in Body Fat (%) entry after you entered the circumferences and pressed Add.
The Waist entry, as distinct from all others, gives the estimate, which is valid not only for adults, but for children also. If you are interested in the waist-to-height ratio only, you may use the Waist entry instead of the Body Fat (%) and save the time on measuring your neck.
You may hide some of the entries above in the settings (☰ -> Entries to show) if you don't use them.
FatOk works in close cooperation with the Apple iPhone Health app. In particular it stores the weight, waist, height and body fat percentage in the common Health App database and you may watch the plot of your weight, waist and body fat percentage with time in the Health App.
Therefore at the first start FatOK ask your permissions to read and write in the common Health App database the height, weight, waist and the body fat percentage. It also asks the permission to read the date of birth to calculate the age, and the sex because in general the estimates are different for men and women and depend on the age.
Before you begin, check that you entered the date of birth and sex (male or female) in Health app. Health App does not allow other applications change this values.
When you run FatOk first time, start from entering the height if it was not entered in Health App because the estimates depend on the height.
WARNING: You should be aware the FatOK gives only the estimates (see the formal medical disclaimer). These estimates are approximately correct for the majority of people but not for all. In case of doubt always seek the advice of your physician or other qualified health provider.
In addition, the caloric intake estimation assume that the level of your weekly physical activity is approximately steady. Be aware, that it may be dangerous for your health to gain or loose your weight too quickly. More exactly, a weight loss of no more than 1 to 2 pounds (0.5 to 1 kg) per week is recommended . The estimates that FatOk makes takes this requirement into account. Again if you feel that the caloric intake estimates don't work for you or in case of doubt seek the advice of your physician or other qualified health provider.
You also should be very careful when you continue to loose your weight in the "healthy" interval. The point is that though the weight of most healthy persons indeed is in the "healthy" interval, it does not mean that each of them can reach any point in the "healthy" interval without the damage for her / his health. The same is true for the waist also.
As for the rate of the probability, a 2010 study that followed 11,000 subjects for up to eight years concluded that waist-to-height ratio is a much better measure of the risk of heart attack, stroke or death than the more widely used body mass index.[9,1]. Also a 2010 systematic review of published studies concluded that waist-to-height ratio may be advantageous because it avoids the need for age-, sex- and ethnic-specific boundary values[9, 10]
In general FatOK estimates of the fitness are approximately valid for the adults of the age 20 years old or older. The US Military Body Fat Standard and body fat percentage estimates are approximately valid for the adults of the age 17 years and older. The Waist-to-height ratio estimates are approximately valid not only for adults, but for children also.
If you don't have FatOK you can download it on the App Store