Natural Pure Keto They work by using certain basic information about the body - height, gender, age and current weight for example and then combining it with the daily activity level. It will then calculate how much weight you have to lose and gauge the amount of time it will take based on the information it has received. Losing weight can be a difficult challenge especially for older people as they tend to traditionally lead a more sedentary lifestyle. In order to succeed and to reach targets it is important to use all the help available.