800 calories is not enough to sustain human life in the long term. Continue that level of nutrition long enough and eventually it will kill you.
Even if you stop way before it kills you, you may still be harmed and the longer you carry it on the more significant and more long lasting the harm will be. Depending on your age, size and the nutritional value of the little food you're eating you could suffer long term cognitive, developmental and psychosocial issues and you risk lasting organ damage that may well both shorten your life and reduce quality of life.
1400 -1500 calories is a very low amount to consider a maintenance level and would represent the maintenance for a very small person living an unhealthily sedentary lifestyle. For most people this would represent a significant calorie deficit.
I'm glad you realise your current behaviour is unhealthy, I'm not sure you understand quite how bad for you it is.
If you are looking for a particular body image or size you need to realise that dieting, particularly extreme diets will never, and I do mean never, help you achieve that image. If you are over your ideal weight (which given your reported past behaviour seems extremely unlikely) the only way to get to where you want to be is to maintain a small calorie deficit over a long period which you generate not by denying yourself food but by increasing physical activity.
If you are already at or below an ideal healthy weight and still aren't satisfied losing more weight will not make you feel better about yourself, again exercise combined with sufficient nutrition to bring you back to a healthy weight is the only workable solution to achieve the image you're looking for.