Will appetite suppressants help with eating less than 400 calories a day?

you need to eat more. no one should eat less than 1200 calories, and 400 is really low. that's putting your body into starvation mode. and with all the exercising, you're probably burning 200+ calories. you need to increase your calories before something bad happens to your body, it's not healthy. and you don't need a diet pill, you're 5'4" and should weigh more than 100 pounds. you will get more energy by eating, and overall feel better.