Our metabolism works most efficiently when we do.

people don't actually need to eat three times a day. it can be a little healthier if we eat 6 small meals a day. i would guess that the difference between us and animals is that we have a faster metabolism and expend more energy. i don't know about lions, but i live around alligators, and they pretty much lie around all day. humans could, however, survive off of one meal a day, or less even. people have undergone 40 day water fasts. we eat three times a day because we have conditioned our bodies to be hungry at those specific meal times.

We are selfish!

Metabolism.

One word - donuts!

I usually eat one meal a day, sometimes more, but seldom do I eat more often. I'm healthy for the most part except the blockage in my arteries which i wouldn't have if i didn't start smoking years ago. Most people, especially Americans are overweight, bloated pigs conditioned to having whatever they want whenever they want it, but the reality is they don't need 3 or 6 meals a day. 1 medium meal will suffice without any noticeable detriment to your health. We do have a faster metabolism though.

Each species is different. Some birds like hummingbirds need to eat all day because of their metabolism. Some animals rarely need to eat as their metabolism dictates. We're all different, what we do is different, the foods we eat, the activities, our brains require nutrition. We also all sleep different amounts. Might as well ask why cats need to sleep 16-18 hours a day and groom for 2-4 when we only need 7-8 hours of sleep and it takes us maybe a few minutes each day to bath.

I usually only eat once or twice a day. It's metabolism. Some birds need to eat the equivalent of their weight every day.

because we exert so much energy in giving out stimulous paychecks and tracking down those greedy bastard pirates..........

&gt;>Why can't humans "hold" the food in their stomachs for longer periods?<< You're on the right track. Herbivores have long intestines, enabling them to extract max nutrients from the nutrient-deficient grass, leaves, seaweed, etc. Carnivores have short intestines b/c their food is "energy rich" in fat & protein, requiring less time to extract the nutrients. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ "Food that contains a lot of cellulose and fiber forms the bulk of a herbivores diet. This diet is difficult to digest. Therefore herbivores need long digestive systems to cope with this material. "Fat and protein form a large part of a carnivores diet. Both are energy rich, so carnivores need to eat less volume. Also, both are easier to digest. Hence carnivores tend to have short digestive systems." ~http://answers.yahoo.com/question/index?qid=20080522143205AAgRAWy ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ "When we kill animals to eat them, they end up killing us because their flesh, which contains cholesterol and saturated fat, was never intended for human beings, who are natural herbivores." ~William C. Roberts, M.D., editor, American Journal of Cardiology http://wiki.answers.com/Q/Are_humans_omnivores_or_herbivores ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Also, from above link: "Length of Small Intestine: CARNIVORE: 3 to 6 times body length HERBIVORE: 10 to more than 12 times body length OMNIVORE: 4 to 6 times body length HUMAN: 10 to 11 times body length." - "Note: Herbivore means exclusive plant eater. It does not mean grass eater, which is a granivore and a type of herbivore. There are many types of herbivores: frugivores, nectavores, folivores, etc." ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ I'm a frigivore. I eat whatever I find in the fridge. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Wow ~ didnt know that about crocodiles! Our food comes a lot easier than what they have to go through to get a meal, and ours tastes better too, hence 3xdaily! That's my unscientific answer!