The answer is "it depends."<br><br>You don't really need any food for the first several days.<br><br>Additionally, the amount of food that you need to maintain your body weight is directly related to your body weight, your activity level, and the environmental conditions.<br><br>In a cold environment, you will need more food than in warm, but if you wear a t-shirt and shorts and are caught in a blizzard with no shelter, you can't eat enough (really can't process what you eat fast enough) to maintain your body temperature.<br><br>If you are in an earthquake, stuck-at-home, and you stay in bed all day, 1200 calories will be more than adequate.<br><br>If you are doing SAR on the collapsed building next door, doing hard physical work for 24 hours straight, 3600 calories won't be enough.