Beneath the bottom of the rearfoot is a fat pad that naturally cushions us and protects the heel as we walk. When walking, you will find a force comparable to nearly 2.5 times body weight on the heel during heel strike, so it ought to be obvious why we need that fat pad. Without that fat pad there would likely be inadequate shock reduction which may result in a number of conditions because of that inadequate shock absorption. The commonest is simply pain under the heel. The pain sensation will mostly be there on weightbearing and not so much on palpation. This may not be a common reason for heel pain, but it is an important cause because it can often be wrongly identified as heel spurs and other reasons. Usually it is not difficult to diagnose as there is just virtually no cushioning under the heel and you will easily notice the bone.
The causes of fat pad atrophy are not totally clear. The fat pad does atrophy as we grow old naturally and in many it just atrophies more at a faster rate. Some people just seem to develop this while others will not. It's not linked to bodyweight issues. It might occur in a number of arthritis problems and athletes because of the years of hitting on the rearfoot can be at a higher risk this condition. People with a higher arched foot (pes cavus) also get a displacement of this fat pad which might give a similar problem to the atrophy.
The only method to manage fat pad atrophy will be to replace the fat or substitute for the fat. This could be inserted in surgically or a cushioning heel pad in the shoes used that has a comparable uniformity to the missing fat pad. Padded shoes could also be used without or with extra cushioning. Surgically this can be an injectable fillers or an autograft using your own fat tissue.