pile on as much meaty chili and cheese and extra bacon as you want, shit even make two, you're not actually going to use all those calories; just eat it all within 5 minutes or so, and then puke it all back up within 30 seconds of finishing. eat some bright green or some bright orange sugar free jello before hand, that way once you start seeing bright green or bright orange and then you're dry heaving you can be sure that you got it all up. your body didn't have much time to start absorbing the nutrients and calories from the meal so it should be far less than 400 calories my friend