Don't waste money in GNC for this stuff, you can get it in walmart or target. just make sure it says pure WHEY PROTEIN on the label. It's no gourmet meal, but it will keep you alive when all the rice and beans are gone. As long as you have drinkable water. Oh, yes...almost forgot. You need a source of saturated fat with pure protein like this. I suggest coconut oil, which you can get in capsules from Puritan's Pride. One a day should be plenty. You can buy it in bulk wherever soapmaking supplies are sold, too. Look for "extra virgin" on the label, and you can be sure it's safe to eat. it will keep forever, and is awesome for cooking. A gallon costs me about $75, but it will last for two or three years.
Thanks!