If you continue calorie counting, restricting your diet and obsessing about your food intake then it might be only a matter of time before a full-blown eating disorder develops. You have developed an unhealthy relationship with food. I would encourage you to focus on what you can do to change your thoughts and behavior regarding food and try to prevent the development of an eating disorder.
There are multiple reasons why you may be engaging in unhealthy food behaviors and illogical body distortions. It could be because your parents are concerned about these matters in their own lives and that has influenced your thinking. There are cases of mothers who have food and body obsessions and not surprisingly, their children (mostly their daughters) do as well. You behavior could be the result of feeling that you have little or no control over a chaotic home environment and managing your food and body weight makes you feel that your life is organized and has order. The way you think and behave might also be influenced by how you “feel” you should look or behave. Part of your letter included a segment in which you mistakenly believe that you’re supposed to be a certain weight to attract a boyfriend or to “live [your] teenage years to the fullest.” There could be other reasons that I did not mention here as well.
Let me point out other specific behaviors and thoughts that are unhealthy or incorrect.
Restricting your diet to 800 calories a day is dangerous. Eight hundred calories is not enough to sustain a healthy functioning body. You also mentioned that you skip meals and feel uncomfortable eating while in the presence of others. This is also a concern and a “red flag.” It is not normal to feel uncomfortable about eating in the presence of others. In addition, you wrote that you have attempted to purge your food after a big meal. Had you been successful, it’s possible that you would meet the diagnostic criteria for a binge eating disorder. From a health perspective, bingeing and purging can lead to chemical and electrolyte imbalances as well as an erosion of your stomach lining and the enamel on your teeth. These are serious health consequences.
With regard to your thinking, you said that you “feel” fat despite what people tell you and you have felt this way since elementary school. You “feel” fat despite not being overweight. According to the Body Mass Index (BMI), the universally accepted tool of measurement in medicine to calculate obesity, a 5’6” individual weighing 140 pounds would be at their “ideal” body weight.
If I were working with you in person, I would try to help you stop reacting to how you “feel” about your weight and try to redirect your focus on truth and facts. In the BMI example mentioned in the previous paragraph, the objective fact is you are not overweight even if you “feel” that you are. This is an example of how you should train yourself to focus on the truth in a situation. You should strive to be logical and to prevent yourself from being guided by your feelings and emotions. You might “feel” fat but in reality you are not. Focus on facts and not on what you “feel” to be true.
It is reasonable to want to lose weight and to be fit and there are healthy ways to do this that do not involve bingeing and purging, skipping meals or severely restricting your caloric intake. You have the wrong ideas about how to lose weight and your attempts at being thin are misguided and dangerous.
I have pointed out that the way you have felt about your body since elementary school is distorted and that your caloric-restricting behavior and relationship with food is unhealthy. Next, it is important that you proactively find a way to change your thinking and behavior.
This problem is not something you should put off or minimize. If you have no one who can help you to correct your thinking and behavior then I would suggest that you consider therapy as way to prevent the possible development of a clinically diagnosable eating disorder. Thanks for writing.