Cos I think I look ugly and diet and exercise is the only form of control I have over my body (can't change my skin colour or the little bump in my nose or that one toe is longer than the rest etc.)
Cos I play netball, tennis, do athletics and need to improve stamina and fitness levels.
Cos having previously suffered an eating disorder, I find that obsessing over exercise is healthier than obsessing over food, to a certain extent.
Cos, sad as it is, seeing gorgeous slim celebrities makes me flinch with envy and if I'm unhappy with my own body I owe it to myself to give it a shot at being half as hot a Gisele Bundchen and Bar Rafaelli, however unachievable.
Cos I worry my bf will stop finding me attractive if I get fat.
Cos I need to work hard to avoid my weight ballooning to the extent where I resemble Michelle McManus.