New Diet - Eat more calories?

800 calories is very low to maintain in the long term. You would be better to up the calories. That way your metabolism is not slowing down to compensate for the very low caloric intake, which will eventually hamper your weight loss goals. A bar of chocolate isn't going to kill you and wouldn't add to your intake substantially more. Keep a log and concentrate more on your body fat percentage rather than what the scales are telling you (i.e. by taking measurements using calipers). Also ensure you are drinking plenty of fresh water. Good luck!