Science Questions

Could humans survive on a raw food diet?

Sun, 23rd Sep 2012

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Sarah Turnbull asked:

Hi Chris et al.,

I love the show and have been meaning to write in for a while to ask you a question.


I heard a scientist make a comment that human beings could not survive for more than three months on raw food alone (I'm pretty sure it was Steve Jones). He made an off-hand remark about us evolving an external stomach for digestion - the frying pan!


So, I would like to ask if this is true, and if so, why.



Sarah Turnbull

Melbourne, Australia





Kat -   This is an interesting one, because human beings have evolved to digest food as we’ve evolved the use of cookery.  So from the development of fire, we humans have evolved, and we’ve evolved cooking skills along with that.

It is possible to survive on a raw food diet, but there are some health risks associated with it.  Some of the studies that have been done on people who have lived on raw food diets for a long time have shown that they tend to be underweight, so there’s a risk of just not getting enough calories in you.  Particularly for women, there’s also a risk of osteoporosis, and not getting enough minerals and vitamins to make healthy bones.  Again, with women, they can have no periods or irregular periods, so that can be a problem.  There’s a big risk, actually, of food poisoning.  One of the most important things that cooking something does is gets rid of the bacteria in it, so there is an increased risk of things like gastroenteritis and food poisoning from eating a lot of raw foods, particularly things like raw milk.  But even salad vegetables, we know that things like E.coli outbreaks can be on salad vegetables.

Chris -   But what about – I went to Leon and had steak tartare a few years back, and very nice it was too, that’s just raw meat, but it’s still meat.  I don’t think there’s any benefit from cooking that apart from the one you mentioned about the fact that you’re going to kill any bugs in it.  And what about people from Japan, for instance, who eat enormous amounts of raw fish?

Kat -   Well there are certainly a lot of raw foods that you can eat that will be perfectly good for you.  Some of the people who go for raw food diets are also vegetarian, so they’ll say “I don’t want to eat anything from animals”, or even vegans, which is really tough, I should imagine...

Chris -   They don’t want to eat a vegan?

Kat -   No! They don’t want to eat anything from animals at all, so they would be vegans themselves.  Eating vegans, if they’re raw, would be part of a raw food diet, I’m sure.  You can eat some raw meats, you can certainly eat some raw fish and fruits, nuts, grains, vegetables, and all of these kinds of things, if you eat them raw, would be part of a raw food diet.  So there are some health risks attached to it, but people can certainly survive on it, yes.

Dave -   I don’t know whether the original quote might have meant that if people lived on a normal diet, but didn’t cook it, they wouldn’t last for three months, because you need higher quality food and you’ve got to eat more of it.

Kat -   I think you do have to think quite hard about it if you’re going to take up a diet like that.

Chris -   So we’re giving it the official “thumbs down”, are we?  Are we saying it probably is more myth than fact?

Kat -   Yes, I think you can definitely survive on a raw food diet, as long as it’s the right kind of raw food diet.


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I think a 3 month time limit would be a gross oversimplification.

I eat most of the products of my garden and orchard raw, uncooked, and generally unwashed (and unsprayed), although I do supplement it a little with some meat as a protein source.  One could, of course, eat raw oysters, or other raw meat products, or perhaps nuts or other high protein foods.

Flour won't kill a person if it is consumed raw...  Ever try a spoonful of raw cookie dough?

One can loose weight consuming a high fruit & veggie diet, but I believe one could find raw higher calorie foods such as nuts that would offset any tendency for weight loss.  And, some of us pack enough extra weight that we could do with a few months of moderate dieting.

One of the issues is the relatively short harvest season in the non-tropical regions.  So, if one is depending on local foods, then one needs to preserve them which may involve some kind of cooking (but not necessarily).  Of course, we can now source foods from around the globe so that isn't as big of a limitation. CliffordK, Mon, 17th Sep 2012

It depends what you mean by 'raw'.

I'm lead to believe you can survive indefinitely on cantaloupe melon, milk and brazil nuts, none of which AFAIK are cooked (don't think the nuts are), in the right proportions I believe it's fully balanced diet.

All bets are off if you're lactose intolerant and have a nut allergy!

But in ancient times I doubt that combination was available, and being able to cook was a massive evolutionary advantage. wolfekeeper, Mon, 17th Sep 2012

Well, "How and when to wean a human infant is a subject of much controversy. The American Academy of Pediatrics recommends feeding a baby only breast milk for the first 6 months of its life, "
rather strongly suggests that we can and do survive for longer than 3 months on raw food.
Bored chemist, Mon, 17th Sep 2012

So what did early humans eat before they accidentally dropped some meat/food on a fire and cook it ? neilep, Mon, 17th Sep 2012

Probably the same kinds of things other primates do; we would have had a much longer gut to digest it; we've had fire for about half a million years or more, plenty of time to evolve a shorter gut. wolfekeeper, Mon, 17th Sep 2012

Nuts are good apparently:

Also a bit of fruit, leaves, grubs, roots etc. wolfekeeper, Mon, 17th Sep 2012

there is an 'ism ... RD, Tue, 18th Sep 2012

In some post-apocalyptic scenario he could well be right. It's all very well saying you can eat vegetables, nuts or what have you, but the problem is finding these things in sufficient quantities, and being able to cultivate them all year round.

Meat is a very important source of protein, and in a return to hunter-gatherer situation it would be difficult to live somewhere like Britain without consuming meat. The bedrock of the point being made is that humans have lost many traits found in our contemporary primates - notably the ability to consume raw meat. We've lost this ability because it's been of no-use since our discovery of cooking. schneebfloob, Tue, 18th Sep 2012

Just to add to my original question:

I believe the idea is not that raw food is bad for you, but that moderns humans can no longer survive on a 100% raw diet. My guess was that we have lost the ability to secrete the enzymes required to extract everything we need from uncooked food.

Thanks everyone for the interesting comments so far. Cheers, Sarah. kushami, Mon, 24th Sep 2012

I think the answer is that there is nothing inherently bad about uncooked food, and our bodies can gain nutrients from both cooked and uncooked food.

As we evolved, undoubtedly there were times of bountiful harvest, and lean times.  It is possible that cooking helped us derive calories and nutrients from low grade food sources during the leaner months.  Cooking can also help kill some pathogens, especially in aging meats.  Simply killing worms before consuming meats could significantly improve our nutritional availability.  Salting, drying, and making jerky, or making some kind of preserves would have been important to extending the availability of food throughout the winter.  Likewise, grains are easy to preserve, and may be more palatable when soaked, cooked, or prepared in some fashion.

However, we now live in a society with year-around availability of fruits, vegetables, milk, high calorie nuts, and etc.  One can even purchase high quality forms of meat such as oysters or lox that are intended to be eaten raw.

You might also have to define "cooked".  For example, Parma Ham is salted and aged, but never actually cooked.  Does that count?  Cheese may also never actually be cooked, and one can get unpasteurized varieties.

Some vitamins are in fact destroyed, or reduced in abundance by cooking.

Anyway, I have no doubt that in modern society, one could derive adequate nutrition from raw foods. CliffordK, Mon, 24th Sep 2012

Although they did boil somethings, the Inuit traditionally ate most food including meat raw or frozen, so it must be possible to survive on it. cheryl j, Wed, 26th Sep 2012

People the question was ..''CAN WE SURVIVE ON A DIET OF ONLY RAW MEAT...NOT ANY FRUIT OR VEGIES ...I think not , you will get scurvey and die ... Albert Mag, Tue, 1st Oct 2013

There can be vitamin C in raw, not cooked, meat ...

But then you increase the risk of being infected with parasites in the raw meat. RD, Tue, 1st Oct 2013

Plenty of people already survive on raw food. It was quite a fad in the Seventies. "Extreme juicers" seem very healthy, if slightly bored. I like to supplement a juice diet with the occasional assiette de fruits de mer, though crabs and prawns really need to be cooked if only to stop them walking off the plate. alancalverd, Tue, 1st Oct 2013

Come on folks ! Eskimo people in Arctic leaves happy on entirety raw meat diet for ages. They do not cook- there is almost no wood to burn. There is no greens as well. And no salt used. Snow is a sours of distilled water. alex, Wed, 9th Apr 2014

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