From a comfort/psychology perspective, I think avoiding hunger pangs is a good thing during any stressful situation, so by all means, pack extra rations. Besides, 1,200 calories is a bare subsistence amount and assumes little physical exertion, like sitting on a lifeboat.

It's not always true that "bigger" (i.e. overweight) people need more calories than skinnier people. Due to low-calorie diets, inactivity, and other factors, an overweight person could have a rather slow metabolism and a low daily caloric requirement vs. the skinny guy who "eats like a horse and doesn't gain an ounce". Even so, everyone has enough fat stores to survive a good long time, if they have water.

Rather than actually needing more calories and feeling hungry, you may feel hungry more easily because your body has gotten very good at converting food into fat, and then not releasing it for energy when needed. As soon as your blood sugar drops, your body senses the need for more calories but since it doesn't want to tap its fat reserves, it screams for more food instead and you feel hungry rather quickly. (A rather simplistic explanation, I admit.)

To counter that tendency in general, you can add a daily dose of low to moderate aerobic exercise which will help train your metabolism to more readily unlock the energy stored in your fat reserves and moderate your blood sugar levels. Train your body to use its own fat more easily, and you should have a better experience of trying to survive with minimal rations. At the very least, by adding some daily exercise, you'll be on your way to losing some weight. <img src="/images/graemlins/smile.gif" alt="" />