Salad Deficiency” Causes Ulcerative Colitis in Gorillas

It’s Prob­a­bly an Impor­tant Cause of Ulcer­a­tive Col­i­tis in Humans, As Well.

Ulcer­a­tive col­i­tis” means open sores in the large intes­tine, which is also called the colon. This con­di­tion can cause severe abdom­i­nal pain and cramp­ing as well as bloody diar­rhea. The “leaky gut syn­drome” that results can cause joint pain and make the per­son feel sick all over.

Wild goril­las eat an extreme­ly high-fiber diet, con­sist­ing main­ly of leaves. Cap­tive goril­las that were fed a low-fiber diet were prone to severe ulcer­a­tive col­i­tis. The same thing might be hap­pen­ing in peo­ple with ulcer­a­tive col­i­tis.

High-fiber veg­eta­bles and fruits have sev­er­al ben­e­fi­cial effects on the large intes­tine:

  • Fiber absorbs water and keeps the mate­r­i­al inside the intestines nice and soft.
  • Fiber makes every­thing go through faster, which means that the wall of the intes­tine gets less expo­sure to harm­ful sub­stances, such as bile acids and free ammo­nia.
  • High-fiber fruits and veg­eta­bles pro­vide impor­tant nutri­ents and antiox­i­dants that are good for the health of the intestines, as well as the rest of the body.
  • Bac­te­ria in the large intes­tine fer­ment some of the fiber, releas­ing short-chain fat­ty acids such as butyrate, which is the favorite fuel of the cells that line the large intes­tine. On a low-fiber diet, those cells could starve to death.

Are Researchers Bark­ing Up the Wrong Tree?
When I looked up what clin­i­cal tri­als were being done on ulcer­a­tive col­i­tis (, I found lots of tri­als of drug treat­ments, some tri­als of “pro­bi­otics” (bac­te­r­i­al cul­tures), a few tri­als of sur­gi­cal treat­ments, and even a few tri­als of psy­chother­a­py and hyp­no­sis. There were some stud­ies in which peo­ple receive butyrate in high-colonic ene­mas. There were even some tri­als in which peo­ple were fed mare’s milk or fish. Apes don’t milk mares or catch fish, so why would any­one imag­ine that peo­ple would have to do that to keep their intestines healthy?

In oth­er words, there were 224 clin­i­cal tri­als involv­ing all sorts of drugs and surgery and so on, but no clin­i­cal tri­als try­ing the obvi­ous ther­a­peu­tic approach, which is a change to a healthy diet. We know that a low-fiber diet caus­es ulcer­a­tive col­i­tis in goril­las, which have a diges­tive sys­tem almost iden­ti­cal to our own. We also know that eat­ing wheat prod­ucts can cause bloody diar­rhea in a tiny minor­i­ty of the pop­u­la­tion. So why isn’t any­one doing research about how to coun­sel peo­ple to solve this prob­lem by cor­rect­ing their diet? Here’s a link to a descrip­tion of a sim­ple yet health­ful exclu­sion diet:

If you want your colon to be healthy, you have to feed it prop­er­ly. If you already have ulcer­a­tive col­i­tis or any oth­er prob­lem with your intestines, ask your doc­tor to refer you to a reg­is­tered dietit­ian (RD) for dietary advice.

How Much Protein Do Gorillas Get From Eating Leaves?

More Than Enough for a Human Being, and Even More Than Enough for a Pig!

Here’s a rather dry and tech­ni­cal arti­cle that describes the amount of “avail­able pro­tein,” as opposed to “crude pro­tein,” in the foods that wild moun­tain goril­las eat.

The moun­tain goril­las in this study were get­ting more than enough pro­tein, main­ly because they were eat­ing so many leaves. Although leaves are low in calo­ries, a sub­stan­tial pro­por­tion of those calo­ries comes from pro­tein. If goril­las eat enough leaves to get enough calo­ries, the pro­tein takes care of itself. A leafy diet is so rich in pro­tein that the goril­las can afford to snack on some low-pro­tein fruit.

Gorillas are big because they are leaf-eaters

Goril­las are big and strong. Like most of the big and strong land ani­mals, they eat leaves. Ani­mals that main­ly eat leaves are called foli­vores. (Foliage means leaves.) In this arti­cle (, some biol­o­gists explain why you would expect a goril­la to be a leaf-eater:

Large mam­malian her­bi­vores, accord­ing to accept­ed eco­log­i­cal the­o­ry, may be expect­ed to feed on abun­dant, low qual­i­ty food as a result of the rela­tion­ship between their body size, meta­bol­ic require­ments, and gut capac­i­ty. … Abun­dant low qual­i­ty food means non­re­pro­duc­tive plant parts, i.e., stems and leaves, because fruit and flow­ers are too ephemer­al to pro­vide a reg­u­lar source of food in bulk for large ani­mals. So, large her­bi­vores ought to be foliv­o­rous in a broad sense, and usu­al­ly are.

Real­ly big ani­mals need to eat a lot of food. Flow­ers and fruit may be tasty but are in short sup­ply. For this rea­son, the real­ly big plant-eaters tend to eat most­ly leaves.

Quick Cauliflower and Potato Curry, Jasmine Rice, Apple and Fennel Salad

This is a quick and easy recipe for enter­tain­ing. The extra turmer­ic is good for you, and it gives the pota­toes and cau­li­flower an appeal­ing yel­low col­or, which looked good with the red toma­toes. I served it with white rice and some pars­ley for gar­nish. For the sal­ad,  I had some fen­nel left over from the day before. The feath­ery greens from the fen­nel bulb dressed up the sal­ad, and were tasty. For dessert, I also had some car­rot cake left over from the day before.

Quick Cauliflower and Potato Curry

2 onions, diced
3 cloves gar­lic, minced or pressed
About 3 medi­um pota­toes, diced
Near­ly half a head of cau­li­flower, cut into flo­rets
1 can diced toma­toes
1 tsp cur­ry pow­der
1 tsp turmer­ic
Pars­ley or kale for gar­nish

Stir-fry the diced onions in a dry skil­let (no oil) until they are very brown. You can add a lit­tle bit of water from time to time if they start to stick. Add the minced gar­lic and fry that for about 30 sec­onds. Then add about 3 cups of water and the pota­toes, cau­li­flower, and diced toma­toes. Add the spices. Cov­er and sim­mer until the pota­toes and cau­li­flower are ten­der. Serve with rice. Gar­nish with pars­ley or kale.

It’s hard to give an exact quan­ti­ty for the pota­toes and cau­li­flower, because their sizes vary, and some skil­lets are big­ger than oth­ers. If I fill my skil­let with veg­eta­bles, it yields about 6 serv­ings.


Because we had com­pa­ny, I want­ed to serve a par­tic­u­lar­ly tasty kind of rice, so I made white jas­mine rice accord­ing to the pack­age direc­tions. I made more than I need­ed, because I would be eat­ing the left­overs for lunch the fol­low­ing day. Jas­mine rice is a nat­u­ral­ly fra­grant rice vari­ety from Thai­land. I didn’t have any brown jas­mine rice, so I used white. Bas­mati rice, brown or white, would also have worked well.

Apple and Fennel Salad

Fresh let­tuce, washed and torn into bite-sized pieces
1 sweet red apple, cored and diced
1 car­rot, peeled and shred­ded
1 stalk of fen­nel, diced
Fen­nel greens for gar­nish
Dress­ing made from rough­ly equal pro­por­tions of bal­sam­ic vine­gar, hon­ey, and pre­pared mus­tard, sprin­kled with thyme

Roasted Autumn Vegetables with Mushroom Gravy, Apple Salad, and Carrot Cake

I put this meal togeth­er because the roast­ed veg­eta­bles and the car­rot cake are both baked at 350 degrees. I pre­pare the veg­eta­bles and put them in the oven, then make the car­rot cake. While the car­rot cake is bak­ing, I have time to make the mush­room gravy and the sal­ad. Then I have time to tidy up the kitchen and set a nice table.

I don’t give mea­sure­ments here, because the veg­eta­bles vary in size any­way. I just keep chop­ping up veg­eta­bles until I have a big serv­ing for each per­son. I used about half of the bulb of fen­nel, so I’d have some left over for sal­ads over the fol­low­ing few days. I also saved all the feath­ery leafy bits of the fen­nel for use in gar­nish­ing sal­ads.

Roast­ed autumn veg­eta­bles
1 bulb of fen­nel
Pota­toes with nice skin, scrubbed
Parsnips, peeled
Sev­er­al cloves of gar­lic, peeled
1 red onion, peeled
1 c water or veg­etable stock

Cut up the veg­eta­bles into small chunks and place them in a bak­ing dish. Mix the herbs into about half a cup of water or stock, with about a table­spoon­ful of bal­sam­ic vine­gar. Pour over the veg­eta­bles. Put it in on the bot­tom rack of the oven and turn the oven on and set it to 350 degrees.

Car­rot cake
After you put the veg­eta­bles in the oven, make the car­rot cake. I used Mary McDougall’s recipe for raisin car­rot cake (, except that I added a half tea­spoon of car­damom and I sub­sti­tut­ed a gluten-free all-pur­pose flour for the whole-wheat flour. Put the cake in the oven on the mid­dle rack. When you put the car­rot cake in the oven, stir the veg­eta­bles and add the rest of the water and herbs.

Apple sal­ad
While the veg­eta­bles and cake are bak­ing, chop up a very sweet red apple, some cel­ery, and some raw Jerusalem arti­chokes (sun­chokes), if you have them. Toss them with a rasp­ber­ry-fla­vored vine­gar and serve on a bed of let­tuce. The vine­gar keeps the apples and sun­chokes from turn­ing dark before you serve them. If your apples aren’t over­ly sweet, you could add a lit­tle bit of the sweet­en­er of your choice to the vine­gar before mix­ing it with the apples.

Mush­room gravy
Stir-fry a chopped onion over medi­um heat in a dry pan until the onion is very brown. Then add two cloves of minced gar­lic and fry for anoth­er minute or so. Then add 2 cups of water and ½ chopped fresh mush­rooms or a hand­ful of dried mush­rooms. Let it sim­mer slow­ly until you are about ready to serve the veg­eta­bles. Then com­bine ¼ cup of corn­starch with anoth­er cup of water. Mix thor­ough­ly, then stir it into the boil­ing mush­rooms. Keep stir­ring until it is thick­ened. You can adjust the amount of water and corn­starch until you get the desired vol­ume and con­sis­ten­cy. Serve the gravy over the roast­ed veg­eta­bles.

Are Gorillas Vegan?

Goril­las are prac­ti­cal­ly veg­an. They eat plants, main­ly leaves. “There is a vir­tu­al absence of foods of ani­mal ori­gin.”

In this study (, some sci­en­tists stud­ied the diet of wild west­ern low­land goril­las, from the Cen­tral African Repub­lic. The goril­las ate about 200 dif­fer­ent species of plants. How­ev­er, they were eat­ing prac­ti­cal­ly no meat. Goril­las do not hunt. They do not fish. They do not keep chick­ens, cows, goats, or sheep. Goril­las do eat a few insects and oth­er creepy-crawlies now and then. In oth­er words, a wild goril­las’ diet is 99.9% veg­an.

How much fat, pro­tein, and car­bo­hy­drate did this veg­an diet sup­ply? By calo­rie, the diet was 2.5% fat, 15.8% car­bo­hy­drate, and 24.3% pro­tein. That’s a lot of pro­tein! Goril­las main­ly eat leaves. Leaves are low in calo­ries, but a lot of their calo­ries are in the form of pro­tein. To get enough calo­ries, a goril­la has to eat a lot of leaves. But if it eats enough leaves to get enough calo­ries, it will auto­mat­i­cal­ly get enough pro­tein.

The sci­en­tists esti­mat­ed that these wild goril­las were get­ting 57.3% of their calo­ries from the fiber in their diet. Dietary fiber includes things like cel­lu­lose, hemi­cel­lu­lose and pectin, which are found only in plants. These sub­stances are made up of long chains of sug­ar mol­e­cules. But ani­mals can­not make the enzymes to break them down into sug­ar again. Thus, they will pass through your small intes­tine intact. But in your large intes­tine, they will be bro­ken down by bac­te­ria. Bac­te­ria can make the enzymes that break down fiber. This process is called fer­men­ta­tion because it does not use oxy­gen in the form of O2. This fer­men­ta­tion process pro­duces some short-chain fat­ty acids, such as butyric acid. These short-chain fat­ty acids are an impor­tant source of ener­gy, par­tic­u­lar­ly for the cells that line the large intes­tine. To learn about short-chain fat­ty acids, click here

Pho­to by jnis­sa

How Strong Are Gorillas?

Goril­las eat a leafy diet. Although leaves are low in calo­ries, a lot of those calo­ries come from pro­tein. So even though goril­las eat no meat, no milk, no fish, and no eggs, they can be tremen­dous­ly strong, about 10 times as strong as a man. Take it from some­one who knows:

No one knows [how strong goril­las are], because you can’t take a goril­la down to your local gym, obvi­ous­ly, and if you did it would be at your own per­il and the oth­er gym mem­bers’ per­il. We don’t know, but sci­en­tists esti­mate it to be about 10 times stronger than a full-grown man. And cer­tain­ly some of the things I’ve seen here at the zoo, 10 times stronger is prob­a­bly fair­ly cor­rect. For exam­ple, when I’m mov­ing things around inside their enclo­sure, there might be very large logs which I’m lit­er­al­ly unable to move, so I might call a cou­ple of oth­er keep­ers over, and between the three of us, we will slow­ly man­han­dle it, per­haps a few inch­es across the enclo­sure. Bob­by then will come in and then just with one hand will be able to swipe that same log a good few feet with­out any effort.

—Daniel Sim­monds, Goril­la Keep­er, ZSL Lon­don Zoo

To under­stand why human beings and goril­las can get enough pro­tein from a plant-based diet, click here.


My book Where Do Goril­las Get Their Pro­tein? What We Real­ly Know About Diet and Health explains every­thing you need to know about nutri­tion for human beings and goril­las!
Cover of book, Where Do Gorillas Get Their Protein?