Record your body weight and check it with chart! You can control your BMI with this application.
By connecting Body Weight Chart, allows you to check your fitness data from multiple devices.
This app also make backup on SD-Card for cell-phone upgrade.

Body mass index (BMI) is a simple index of weight-for-height that is commonly used to classify overweight and obesity in adults. It is defined as a person's weight in kilograms divided by the square of his height in meters (kg/m2).
For adults, WHO defines overweight and obesity as follows:

overweight is a BMI greater than or equal to 25; and
obesity is a BMI greater than or equal to 30.
BMI provides the most useful population-level measure of overweight and obesity as it is the same for both sexes and for all ages of adults. However, it should be considered a rough guide because it may not correspond to the same degree of fatness in different individuals.
(from WHO website Obesity and overweight )