Being FAT is not the end of the World.
One of the most interesting things about how a person looks is that it does not always signify their behaviour or lifestyle. For example there are a lot of people out there with less then ideal eating habits that are skinny. There are also a lot of people with perfect eating habits that are fat.
Being fat does not automatically equal being an overeater or a non-exerciser. This is because of our complex human physiology that is so individualised that what may work for one person will probably not work for another.
Factors such as genetics, age, underlying medical conditions as well as diet and exercise history will all have an impact upon an arbitrary figure on the scale as well as on performance. Just because the person has gained weight does not mean that they have gained fat.
The opposite is also true just because someone has lost weight it does not mean that they have lost fat. The cases where people maintain their weight may also be cause for concern as to what is happening for that maintenance to occur.
What we as society need to be careful about when making an assumption on dietary habits of a fat or skinny person is that these assumptions if verbalised will have an impact of those who do have an issue with food. The same can also be said for calling someone fat or skinny.
Research has shown that by the consistent calling of a person as fat or skinny by the age of 10 had a very strong correlation to eating disorders and obesity later in adult life. This correlation was particularly strong for girls.
Your sense of self worth should not be based on your looks and your perceived or actual relationship with food.