Why Do Chimpanzees Eat Meat?

Chim­panzees eat meat for two sim­ple rea­sons: they can catch it and they like it. Chim­panzees are par­tic­u­lar­ly like­ly to eat meat dur­ing the dry sea­son, when short­ages of the foods that nor­mal­ly make up the bulk of theirdi­et cause them to lose weight. Although the meat may be a use­ful source of calo­ries dur­ing the dry sea­son, wild chim­panzees don’t need to include meat or any oth­er ani­mal-based food in their diet to ful­fill their needs for pro­tein or any of the amino acids. In fact, plants pro­vide all of the nutri­ents that are known to be essen­tial for a chim­panzee, except for vit­a­min D (which they get from the abun­dant sun­shine in Africa) and vit­a­min B12 (which comes from bac­te­ria).

Many peo­ple think that I am sil­ly for ask­ing where goril­las get their pro­tein. They tell me that I should talk about chim­panzees instead. Often, they inform me that chim­panzees are far more sim­i­lar to human beings than goril­las are, as if I couldn’t tell that just by look­ing. These peo­ple are miss­ing my point: goril­las are the largest and most pow­er­ful liv­ing pri­mate and yet are the clos­est to fol­low­ing what human beings would con­sid­er a veg­an diet. Chim­panzees and human beings don’t need to eat meat to grow up big and strong because goril­las grow up to be far big­ger and stronger with­out it. Lawyers may rec­og­nize this as an a for­tiori argu­ment.

If a male goril­la, whose diges­tive sys­tem is prac­ti­cal­ly iden­ti­cal to a human being’s, can get enough pro­tein from veg­eta­bles to grow to weigh more than 400 pounds and be ten times as strong as a man, why shouldn’t I expect that a rel­a­tive­ly puny human Olympic weightlifter could also get enough pro­tein from a plant-based diet? My intent is to ridicule the Four Food Groups dog­ma that I was taught in sixth grade.

Goril­las don’t hunt or fish, and they don’t keep cows or chick­ens. As a result, they don’t eat meat or fish, dairy prod­ucts or eggs. The only ani­mal-source food they eat is “the oth­er, oth­er white meat”: ter­mites, slugs, and oth­er creepy-crawlies. These foods would make an insignif­i­cant con­tri­bu­tion to the goril­las’ pro­tein intake, which is already high because pro­tein accounts for a high per­cent­age of the calo­ries in leaves.

Bugs and slugs could be a use­ful source of vit­a­min B12, a micronu­tri­ent that is made by bac­te­ria in their intestines. Vit­a­min B12 is also pro­duced by bac­te­ria in a primate’s gas­troin­testi­nal tract. How­ev­er, the vit­a­min may be pro­duced so far along in the intesti­nal tract that it isn’t absorbed effi­cient­ly. No plants make vit­a­min B12, but goril­las and chim­panzees can prob­a­bly get enough vit­a­min B12 from the bac­te­ria in the bugs they eat and in the dirt that clings to their food. Plus, apes are not metic­u­lous about wash­ing their hands, if you get my drift. If you are wor­ried about get­ting enough vit­a­min B12, you don’t have to eat dirt or bugs. You can get it in a nice, clean tablet instead.

I don’t ask where chim­panzees get their pro­tein because chim­panzees do eat some meat. Chim­panzees prob­a­bly eat less meat than just about any human pop­u­la­tion oth­er than Bud­dhist monks. Nev­er­the­less, many peo­ple want to use chim­panzees’ meat con­sump­tion as an excuse for humans to eat meat.

The fact that chim­panzees’ meat con­sump­tion is large­ly sea­son­al goes far toward explain­ing why human beings have always eat­en meat. Chim­panzees are most like­ly to eat meat dur­ing the time of year when they are los­ing weight because their usu­al foods are in rel­a­tive­ly short sup­ply. Peo­ple think of meat as a source of pro­tein, but it’s main­ly a source of calo­ries, espe­cial­ly from fat. Meat is also a good source of sodi­um, which is in rel­a­tive­ly short sup­ply in the chim­panzees’ fruit and veg­etable diet.

The fact that chim­panzees eat the most meat dur­ing times of food short­ages sug­gests that their food choic­es fol­low a pat­tern that biol­o­gists call opti­mal for­ag­ing the­o­ry. Ani­mals try to get the most calo­ries for the least effort and with­out get­ting hurt. Opti­mal for­ag­ing the­o­ry explains why chim­panzees eat meat but goril­las don’t, and why chim­panzees eat more meat dur­ing times of food short­age.

Chim­panzees are main­ly fruit eaters, but they also eat a lot of veg­eta­bles. The prob­lem with fruit is that it’s sea­son­al. Worse yet, a fruit tree rep­re­sents a rich enough source of calo­ries that ani­mals will fight over it. When fruit is scarce, chim­panzees can use the skills they devel­oped in fight­ing over the fruit to engage in preda­to­ry behav­ior. Also, chim­panzees are small enough and fast enough that they are rea­son­ably good hunters.

Goril­las, on the oth­er hand, main­ly eat leaves. There are gen­er­al­ly plen­ty of leaves to go around, and a leafy plant is gen­er­al­ly so poor in calo­ries that it’s not worth fight­ing to pro­tect. To sub­sist on leaves, how­ev­er, you have to eat an enor­mous vol­ume of food. Since leaves are so low in calo­ries, leaf-eaters have to be good at con­serv­ing their ener­gy. That’s why goril­las have such a placid dis­po­si­tion. For a goril­la, hunt­ing is sim­ply not worth the effort. They are too big and slow to catch very much, and they’re large enough that they’d risk injury if they got too reck­less.

Chim­panzees use twigs to fish for ter­mites, and goril­las don’t. Some peo­ple think that this fact means that chim­panzees are smarter than goril­las. I don’t. If you are a juve­nile goril­la or a preg­nant or nurs­ing female goril­la, you don’t need to mess around with a lit­tle bit­ty twig to get a few ter­mites. All you have to do is wait for the sil­ver­back to knock over a rot­ting tree. Then all of you can eat as many ter­mites as you’d like.

Some peo­ple have argued that the bal­ance between ani­mal and plant foods in a hunter-gath­er­er society’s diet rep­re­sents the opti­mal bal­ance for human nutri­tion. I think that’s idi­ot­ic. Hunter-gath­er­er peo­ples (or should I say, gath­er­er-hunter peo­ples) tend to fol­low opti­mal for­ag­ing the­o­ry just like any oth­er oppor­tunis­tic feed­er. Their goal is to sur­vive in the short term, not to avoid breast or prostate can­cer in mid­dle or old age. The main threat to their short-term sur­vival is star­va­tion.

Meat rep­re­sents a con­cen­trat­ed source of calo­ries. The fact that a rel­a­tive­ly high per­cent­age of these calo­ries comes from pro­tein is actu­al­ly a dis­ad­van­tage. Hunt­ing peo­ples pre­fer the fat­ti­est foods. Peo­ple who end up hav­ing to sub­sist on extreme­ly low-fat meat, such as rab­bit, are prone to a prob­lem called fat-hunger or rab­bit star­va­tion. This prob­lem prob­a­bly results from a diet that has too much pro­tein and not enough car­bo­hy­drate or fat. On a low-carb diet and dur­ing star­va­tion, the body has to make its sug­ar sup­ply out of pro­tein. Per­haps the body can make only so much sug­ar out of pro­tein. As long as you are eat­ing enough fat to meet most of your ener­gy needs, your body can make enough sug­ar out of pro­tein to feed your brain. If you were eat­ing pro­tein but not enough fat or carbs, you could end up in seri­ous trou­ble. So you could end up in trou­ble from a diet that is too high in pro­tein. In con­trast, it is prac­ti­cal­ly impos­si­ble to avoid get­ting enough pro­tein, as long as you are eat­ing enough unre­fined plant foods to get enough calo­ries.

Famine is not a sig­nif­i­cant cause of death in the Unit­ed States. In fact, peo­ple in the Unit­ed States are far more like­ly to die of the dis­eases of afflu­ence, such as heart dis­ease and can­cers of the breast and prostate. Ani­mal-based foods and fat­ty processed foods are the main con­tribut­ing caus­es of the dis­eases of afflu­ence. The abil­i­ty to use ani­mals for food may have helped human beings sur­vive to the mod­ern era, espe­cial­ly in the Arc­tic, but ani­mal-based foods are a major cause of death and dis­abil­i­ty in the Unit­ed States today. Think about that the next time you hear some­one pro­mot­ing a “Paleo” diet.

A Fish Is Not a Vegetable!

Late­ly, lots of peo­ple have been claim­ing that seafood is an impor­tant part of a health-pro­mot­ing diet for human beings. Some of the hype comes from the seafood indus­try, and some of it comes from peo­ple who sim­ply want an excuse to eat seafood. In real­i­ty, the health ben­e­fits of the so-called pesc­etar­i­an diets (a veg­e­tar­i­an diet plus seafood) result from the fact that they include a lot more starch and veg­eta­bles than is cus­tom­ary in the stan­dard Amer­i­can diet, while exclud­ing some of the most dan­ger­ous ani­mal-based foods. The starch and veg­eta­bles are good for you. Avoid­ing meat and milk from mam­mals and meat and eggs from birds is good for you. Unfor­tu­nate­ly, the wine and seafood and olive oil in the “Mediter­ranean” diet do more harm than good.

It has always struck me as illog­i­cal for peo­ple to call them­selves veg­e­tar­i­an if they eat seafood, which is the gen­er­al term used to include edi­ble fish and shell­fish. (Yes, there are some edi­ble plants that grow in sea­wa­ter, but they’re gen­er­al­ly called sea veg­eta­bles rather than seafood.) Fish are not veg­eta­bles. They are ani­mals. So are shell­fish, a cat­e­go­ry that includes mol­lusks such as oys­ters and crus­taceans such as shrimp and lob­ster. If you are eat­ing ani­mals, you’re not veg­e­tar­i­an.

Many peo­ple eat fish because they are afraid that a pure­ly plant-based diet wouldn’t pro­vide enough pro­tein to main­tain their health. That’s non­sense. Pro­tein defi­cien­cy is sim­ply not a real con­cern. As long as you get enough calo­ries from any prac­ti­cal diet based on unre­fined plant foods, you will auto­mat­i­cal­ly get enough protein—unless you have some bizarre diges­tive or meta­bol­ic dis­ease.

Rather than wor­ry­ing about not get­ting enough pro­tein, most peo­ple should be wor­ried about the effects of eat­ing too much pro­tein. When you eat more pro­tein than you need, your body turns the excess amino acids to sug­ar, releas­ing tox­ic waste prod­ucts such as ammo­nia and sul­fu­ric acid. In con­trast, burn­ing car­bo­hy­drates and fats for ener­gy pro­duces just car­bon diox­ide and water. The tox­ic byprod­ucts of a high-pro­tein diet can harm the liv­er and kid­neys, as well as pro­mot­ing osteo­poro­sis. One study showed that peo­ple from the North Slope of Alas­ka had high rates of bone loss as a result of their high-pro­tein diet, even though their cal­ci­um intake was high because they were eat­ing fish bones.

Seafood is ani­mal tis­sue, and it has the same faults as any oth­er ani­mal tis­sue. It con­tains cho­les­terol, too much pro­tein and fat, and no starch or fiber. Fish and oth­er sea crea­tures don’t pro­vide any essen­tial nutri­ents that you can’t eas­i­ly get from oth­er sources. Plants con­tain all of the nutri­ents that are essen­tial in human nutri­tion except for vit­a­min D (which you get from sun­shine) and vit­a­min B12 (which comes from bac­te­ria). Even the omega 3 fat­ty acids in fish oil came from the plants that were at the bot­tom of the fish’s food chain.

Anoth­er prob­lem with ani­mal tis­sue, includ­ing seafood, is the buildup of tox­ic sub­stances, includ­ing heavy met­als and fat-sol­u­ble chem­i­cals such as diox­in. This prob­lem is called bioac­cu­mu­la­tion. The high­er up in the food chain an ani­mal is, the worse this prob­lem tends to be. You can avoid this prob­lem by eat­ing plants instead of ani­mals.

In short, the hype about a “pesc­etar­i­an” diet is just hype. Peo­ple are bet­ter off just eat­ing plants.

Pho­to by Pardee Ave.

Starchy, Low-Fat Diets Reduce Deaths From Type 2 Diabetes

Here is an inter­est­ing arti­cle that was pub­lished in the Pro­ceed­ings of the Roy­al Soci­ety of Med­i­cine in 1949. It points out that type 2 dia­betes is com­mon in places where peo­ple eat a fat­ty, low-carb diet and rare in places where peo­ple eat a starchy, low-fat diet. When a pop­u­la­tion that had been eat­ing a fat­ty diet switch­es to a starchy diet, such as under rationing in wartime, the num­ber of peo­ple who die of com­pli­ca­tions of dia­betes falls off dra­mat­i­cal­ly. See the graph on page 324 to see the effects of rationing, eco­nom­ic slump, and the intro­duc­tion of insulin ther­a­py on the num­ber of peo­ple who died of dia­betes in Eng­land and Wales in the ear­ly 20th cen­tu­ry.

The author point­ed out that you can see the same rela­tion­ship between high fat con­sump­tion and deaths from dia­betes all over the world:

There thus seems to be a uni­ver­sal rela­tion between diet and dia­bet­ic mor­tal­i­ty. The dietet­ic fac­tor most close­ly relat­ed is fat con­sump­tion.

It may seem odd that the intro­duc­tion of insulin ther­a­py didn’t make a dent in the graph.  That’s because most peo­ple with dia­betes have type 2 dia­betes, which used to be called non–insulin-dependent dia­betes. You’d see a dif­fer­ent pic­ture if you looked at a graph of deaths from type 1 dia­betes, which used to be called insulin-depen­dent dia­betes.

Note: For a clear expla­na­tion of why high-car­bo­hy­drate diets are good for peo­ple with any type of dia­betes, see my book Thin Dia­betes, Fat Dia­betes: Pre­vent Type 2, Cure Type 2.

Behind Barbed Wire_Print

Where Do Elephants Get Their Protein?

I chose the goril­la motif for this blog because goril­las are the biggest and most pow­er­ful pri­mates, along with being about as close as pos­si­ble to veg­an as you can get while eat­ing many pounds per day of veg­e­ta­tion in a rain for­est. I want­ed to point out that peo­ple sim­ply don’t have to wor­ry about get­ting enough pro­tein or cal­ci­um from a plant-based diet. In real­i­ty, the ani­mal-based foods that we have been urged to eat don’t pro­vide any nutri­ents that we can’t eas­i­ly get from plants or bac­te­ria. If you are still wor­ried about pro­tein, think about where ele­phants get their pro­tein. Ele­phants are even big­ger and even stronger than goril­las. A big ele­phant can eat up to 600 pounds of food a day.

Pho­to by mcough­lin

Is the Child Resisting Toilet Training? Or Merely Constipated?

Yes­ter­day, a friend of mine told me about a four-year-old boy who was “resist­ing” being toi­let trained. She said that the child would uri­nate in the toi­let but that he’d “hold it” for three days rather than defe­cate in his pot­ty. I told her that I couldn’t imag­ine that any­body who eats a high-fiber veg­an diet could “hold it” for three days, even if he tried, unless he was tak­ing mor­phine or some oth­er drug that shuts down gut motil­i­ty. I said that the child’s prob­lem didn’t sound to me like resis­tance to pot­ty train­ing. It sound­ed like con­sti­pa­tion. His refusal to go on the pot­ty prob­a­bly reflects the fact that his bow­el move­ments are uncom­fort­able or even ago­niz­ing­ly painful, and it’s prob­a­bly because he’s being fed dairy prod­ucts and a lot of processed food. She admit­ted that the poor child was being fed cow’s milk and wasn’t eat­ing much fruit and veg­eta­bles or even whole grains.

Think about it. If you are a tod­dler or preschool­er and have had some painful expe­ri­ences on the pot­ty, wouldn’t you avoid the pot­ty the way you’d avoid any tor­ture device? Painful expe­ri­ences have trained the child to avoid the pot­ty. I can only hope that the poor child’s care­givers aren’t adding to the child’s mis­ery by pun­ish­ing him for fail­ing to use the pot­ty.

Bow­el move­ments aren’t sup­posed to hurt. If a child’s bow­el move­ments are infre­quent or dif­fi­cult, there is some­thing wrong. The usu­al cause of the prob­lem is the diet.

Cow’s milk and oth­er dairy prod­ucts are a com­mon cause of severe con­sti­pa­tion in chil­dren. The diges­tion of casein, which is the major pro­tein in cow’s milk, pro­duces pro­tein frag­ments that are called caso­mor­phins because they have drug effects that are sim­i­lar to those of mor­phine. Besides being slight­ly addic­tive, caso­mor­phins can cause severe con­sti­pa­tion. For­tu­nate­ly, human beings do not need to con­sume any cow’s milk prod­ucts at all, ever.

A low-fiber diet is also a com­mon con­tribut­ing cause of con­sti­pa­tion in chil­dren. Ani­mal-based foods all con­tain zero fiber, and refined plant foods con­tain very lit­tle fiber. As a result, the stan­dard Amer­i­can diet, which is based on ani­mal-source foods (includ­ing dairy prod­ucts) and refined foods, is a recipe for con­sti­pa­tion. It is also a major cause of appen­dici­tis, which can be dead­ly. If all of the foods that a child is offered con­tain fiber, the child will eat fiber.

Often, a child’s refusal to use the pot­ty is viewed as a prob­lem with the child’s behav­ior. How­ev­er, I think that when a child doesn’t poop for three or more days, it’s prob­a­bly the care­giv­er, not the child, who is mis­be­hav­ing. The care­giv­er is prob­a­bly fail­ing to feed the child the kind of diet that would enable the child to have nor­mal bow­el move­ments. Any health­care pro­fes­sion­al who sug­gests drug treatments–even over-the-counter laxatives–or behav­ioral inter­ven­tions with­out teach­ing the care­givers how to cor­rect the child’s diet is also mis­be­hav­ing, in my hum­ble opin­ion.

Online course in nutrition from Cornell University

Cor­nell Uni­ver­si­ty is offer­ing an online course in nutri­tion, under the super­vi­sion of T. Col­in Camp­bell, PhD, a nutri­tion­al bio­chemist who is also one of the world’s fore­most author­i­ties on nutri­tion­al epi­demi­ol­o­gy. The course pro­vides essen­tial infor­ma­tion for health­care pro­fes­sion­als (doc­tors, nurs­es, chi­ro­prac­tors, dieti­tians, nutri­tion­ists), patients, teach­ers, par­ents and any­one in the gen­er­al pub­lic with an inter­est in reach­ing opti­mal health and dietary excel­lence. Med­ical doc­tors who take the course can get 19 Con­tin­u­ing Med­ical Edu­ca­tion cred­its for tak­ing the course.

Type 1 Diabetes: It’s the Milk, Not the Shots!

I was lis­ten­ing to a self-edu­cat­ed, self-styled health expert who was talk­ing on the radio yes­ter­day. He said some­thing about some vit­a­min ther­a­py for type 1 dia­betes, and then he said some­thing that shocked and upset me. He men­tioned what he believes is the cause of type 1 dia­betes. I expect­ed him to say “cow’s milk.” There’s plen­ty of evi­dence to sup­port the role of cow’s milk in caus­ing type 1 dia­betes. If more par­ents knew about the link between cow’s milk and type 1 dia­betes, it’s like­ly that few­er chil­dren would come down with type 1 dia­betes. Instead, he said, “vac­ci­na­tions.” I’d nev­er before heard of any link between vac­ci­na­tions and type 1 dia­betes, so I quick­ly did a MEDLINE search. I looked for arti­cles on vac­ci­na­tions and the cause of type 1 dia­betes in humans. If you click on this link, you’ll see the same arti­cles I did:


For me, this search yield­ed 60 arti­cles, many of which I could read for free. By the time that you repeat this search, there may be more. Some of them were about the abil­i­ty of vac­cines to pro­vide pro­tec­tive immu­ni­ty in chil­dren who already had type 1 dia­betes. Sev­er­al arti­cles were about the attempts to devel­op a vac­cine to pre­vent type 1 dia­betes.

One arti­cle point­ed out that rubel­la infec­tion was the only infec­tious dis­ease that has been clear­ly impli­cat­ed as a con­tribut­ing cause of any form of type 1 dia­betes. Of course, rubel­la could be com­plete­ly erad­i­cat­ed, along with measles, if all of the world’s coun­tries par­tic­i­pat­ed in a com­pre­hen­sive vac­ci­na­tion cam­paign. Unfor­tu­nate­ly, many peo­ple are refus­ing to get their chil­dren vac­ci­nat­ed against rubel­la because they are con­vinced that the MMR vac­cine caus­es autism. I remem­ber one woman in par­tic­u­lar telling me that her child’s autism result­ed from mer­cury in the MMR shot. I told her that I was sor­ry that her child has autism, but I can guar­an­tee that mer­cury in the MMR shot had absolute­ly noth­ing to do with it. That’s because the mer­cury-con­tain­ing preser­v­a­tive thiom­er­sal has nev­er been used in the MMR vac­cine. I also explained to her that since con­gen­i­tal rubel­la infec­tion is a pos­si­ble cause of autism-spec­trum dis­or­der, then her efforts to scare peo­ple away from the MMR vac­cine might make the prob­lem worse, not bet­ter. If the world’s pop­u­la­tion worked togeth­er to erad­i­cate measles, mumps, and rubel­la, then the MMR vac­cine would no longer be need­ed.

The stud­ies that looked for evi­dence of a sta­tis­ti­cal rela­tion­ship between var­i­ous vac­ci­na­tions or vac­ci­na­tion sched­ules and type 1 dia­betes kept com­ing up emp­ty-hand­ed. As the biggest and best-designed study con­clud­ed:

These results do not sup­port a causal rela­tion between child­hood vac­ci­na­tion and type 1 dia­betes.

If there real­ly were some sort of cause-and-effect rela­tion­ship, it would leave some evi­dence of its exis­tence. In oth­er words, we don’t have an absence of evi­dence, we have evi­dence of absence! There’s no ratio­nal rea­son to blame vac­ci­na­tions for caus­ing type 1 dia­betes!

So far, vac­ci­na­tion cam­paigns have led to the com­plete erad­i­ca­tion of two infec­tious dis­eases: small­pox and rinder­pest. Small­pox is a human dis­ease that was once a major cause of death and dis­fig­ure­ment. Rinder­pest killed hun­dreds of mil­lions of cat­tle. The next human dis­ease that is about to be erad­i­cat­ed by vac­ci­na­tion is polioGuinea worm dis­ease (dra­cun­cu­lia­sis) is about to be erad­i­cat­ed by a cam­paign of edu­ca­tion about san­i­ta­tion. It is tech­ni­cal­ly pos­si­ble to erad­i­cate measles, mumps, rubel­la by vac­ci­na­tion and lym­phat­ic filar­i­a­sis (ele­phan­ti­a­sis) and cys­ticer­co­sis (pork tape­worm) by oth­er meth­ods. There is even talk of erad­i­cat­ing malar­ia.

Nowa­days, it’s no longer nec­es­sary to vac­ci­nate peo­ple against small­pox. Soon, it will no longer be nec­es­sary to vac­ci­nate peo­ple against polio. I look for­ward to the day when measles, mumps, and rubel­la are erad­i­cat­ed and the MMR vac­cine will no longer be need­ed. In the mean­time, there’s no need to wor­ry that the cur­rent­ly used vac­ci­na­tions pose any risk of type 1 dia­betes.

no-more-measles-coverNote: Most of the peo­ple who build anti­vac­cine Web sites and pro­duce anti­vac­cine doc­u­men­taries have a prof­it motive. Some of them are faith heal­ers who want you to put mon­ey in their col­lec­tion plate. Oth­ers are sell­ing over­priced vit­a­mins and unproven herbal reme­dies over the Inter­net. Still oth­ers are pro­vid­ing some sort of ser­vice that has nev­er been proven to be safe and effec­tive. A few of them run non­prof­it orga­ni­za­tions that give them a salary. To get you to sup­port them finan­cial­ly, they need to under­mine your trust in your fam­i­ly doc­tor. For that rea­son, they attack the sin­gle most impor­tant ser­vice that con­ven­tion­al med­i­cine can pro­vide: immu­niza­tion against seri­ous dis­eases that do not respond well to any avail­able treat­ment. I explain the his­to­ry and moti­va­tions of the anti­vac­ci­na­tion move­ment in detail in my book No More Measles! The Truth About Vac­cines and Your Health.