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.

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

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.

Predators Aren’t the Top of the Food Chain, Their Parasites Are!

Lots of people tell me that human beings are supposed to be predators and carnivores—that we’re supposed to be the top of the food chain! This makes human beings sound really important and special, doesn’t it? There’s only one small problem with this idea. The apex predator of an ecosystem (i.e., a predator that has no predators of its own) is not really at the top of its food chain. The creatures at the very tippy top of the food chain are the parasites that feed on the apex predator. Here’s a link to an article that describes the protozoa, worms, and mites that were found in the droppings of wild lions in Tanzania. These parasites are the sort of creatures I think of when someone mentions the top of the food chain! Not so glamorous, is it?

The idea that human beings should be at the top of the food chain and therefore should or must kill and eat other animals to maintain some sort of special status sounds to me like a weird and dangerous form of narcissism. It asserts that we are special and entitled to special privileges, but it bases that exalted status on primitive animalistic behaviors, not on the abilities and accomplishments that are unique to our species. We’re the only known species in the universe with whom it is even theoretically possible to hold an intelligent conversation. We’re the only ones who can contemplate and deliberately shape our own destiny. Those uniquely human gifts make us special, even if we eat the low-fat plant-based foods that are good for our health instead of the fatty, meaty foods that are the major cause of death and disability in the United States.

The Cause of the Breast Cancer Epidemic

October is Breast Cancer Awareness Month, and we’re inundated with pink ribbons, urging us to be “aware” of breast cancer and encouraging women to get mammograms. Personally, I didn’t need to be made aware of breast cancer. It devastated my family about 40 years ago, when my father’s eldest sister, who was more like a mother to him, died of it after a long and horrible illness. About 10 years later, another of his sisters began her long and painful struggle against the disease that eventually claimed her life. Recently, some of my friends have undergone mastectomies. It would hard for me to be more aware that breast cancer exists.

What infuriates me is that the attempts to raise “awareness” of breast cancer systematically fail to tell women the single most important thing they can do to reduce their risk of dying of breast cancer: correct their diet. Instead, it urges them to do something that might have little or no effect on their survival: get an annual mammogram. It would be as if the efforts to educate the public about lung cancer all failed to mention cigarettes but instead just urged everyone in the population to get an annual chest x-ray.

By the mid 20th century, European and U.S.-trained doctors who were practicing in Africa and Asia realized that breast cancer is rare to practically nonexistent in populations that eat a low-fat, plant-based diet. By the end of the 20th century, epidemiologists knew that breast cancer mortality is strongly linked to the amount of animal protein that a population consumes. The more animal protein a population eats, the more likely its women are to die of breast cancer. Vegetables had the opposite effect. The more vegetables a population eats, the less likely their women are to die of breast cancer.

The data on breast cancer mortality boil down to a simple lesson: if women ate low-fat plant foods instead of a fatty, animal-based diet (including meat, milk, fish and eggs), they could dramatically reduce their risk of dying of breast cancer–and colon cancer, and heart disease, and diabetes, and autoimmune disease, etc. etc. etc. They’d even reduce their risk of getting varicose veins! Even if a woman already has cancer, a switch to a low-fat, plant-based diet might improve her chances of survival.

Instead of being given advice that will actually prevent breast cancer, women in the United States are urged to get a routine annual mammogram. Unfortunately, mammograms do absolutely nothing to prevent breast cancer, and they may do little or nothing to keep most women from dying of breast cancer. Worse yet, routine mammography may lead to unnecessary surgical procedures in women who don’t have cancer.

The decision of who should undergo mammography and when they should undergo it is complicated. The next time you hear someone urging all women of a certain age to have annual screening mammograms, consider the following:

  • Mammography involves exposing the breast to x-rays and thus might actually cause some cancers. The x-rays could pose a particular problem for young women and women with a genetic predisposition to breast cancer.
  • The breast is typically squashed flat while the mammogram is being taken. Not only does this compression hurt, it could break up a precancerous lesion, turning it into a deadly invasive cancer.
  • Mammography is less useful for finding cancers in the breasts of premenopausal women because their breast tissue is denser.
  • By the time a cancer is large enough to be seen by mammography, it may already have spread.
  • Mammograms often cause false alarms by bringing attention to harmless benign lesions, as well as to cancerous tumors that would have gone away by themselves if left untreated. Unfortunately, the woman has to undergo the pain and expense and risk of a surgical biopsy to find out whether the lesion is benign or not, and she’ll never know whether her body’s immune system would have destroyed a tumor before it caused any problems.

Many studies have failed to show that routine screening mammography provides any benefit in terms of saving lives. As a result, some experts argue that it is a pointless and cruel waste of medical resources to urge all women to have annual screening mammography. Even the value of routine breast self-examination has been questioned. Nevertheless, mammography could still be valuable for many individual patients, depending on the situation. The real question is when and how often and for whom it should be used.

Photo by maf04

Host a Screening of Forks Over Knives

If you haven’t seen it already, watch the documentary Forks Over Knives. You can watch it instantly on Netflix if you are a Netflix subscriber. You can also order the DVD at www.forksoverknives.com and host your own screening.

The documentary includes this juicy quote from T. Colin Campbell, PhD, who is one of the world’s most prominent nutrition scientists:

I know of nothing else in medicine that can come close to what a plant-based diet can do. I can say this with a great deal of confidence, that our national authorities are simply excluding this concept of nutrition from the debate, in the discussion, in order to protect the status quo. In theory, if everyone were to adopt this, I really believe that we could cut healthcare costs by 70% to 80%.

How to Cook Dried Beans, Lentils, and Peas

It’s easy to get enough protein from a plant-based diet, even if you don’t eat legumes (beans, lentils, and peas). In fact, the Pythagoreans of ancient Greece thrived on a purely plant-based diet, even though they refused for philosophical reasons to eat beans. Nevertheless, beans are cheap, tasty, and nutritious and play an important part in many traditional cuisines. The only problem is that dried beans can be hard to cook. I’ve tried several different methods and have had good luck with all of them.

If you want to use dried beans instead of canned beans, you’re going to have to think ahead and allow time for the beans to soak and cook. I usually soak them overnight and then cook them the following day. I often cook a huge pot of beans and then use the cooked beans in various recipes over the next few days. For example, I mash some of the beans with a little bit of chili powder and salt and use them as sandwich filling. Or I can add chick peas or other beans to a salad.

If you want to cook chick peas, use soft water, such as rainwater. If you use hard water, the chick peas will never soften! We have really hard water, so I use water from a reverse osmosis filter when I cook chick peas. I can use regular tap water for other kinds of beans.

The first step in cooking dried beans is to sort through them to make sure that no pebbles are hiding among the beans. I simply pour them into my hand a few at a time and then toss them into a bowl. For small beans like lentils, I scatter them a handful at a time onto a white plate and pick through them before tossing them into the bowl. You can cook lentils and peas right away. I soak larger beans overnight before cooking them.

I use any of several methods to cook beans. The traditional method used by the Native Americans of New England was to put the beans and water and maybe some maple syrup in a crockery pot and leave it by the fire. The Puritans of New England adopted a similar practice because they strictly observed the Sabbath, which meant that they couldn’t work on Sundays. They realized that they could have a hot, cooked meal on Sundays if they left a pot of beans and a crockery of coarse bread dough in a hot brick oven on Saturday night. The fact that nearly everyone ate beans on Sundays is why Boston is called Bean Town.

With the rise of the sugar plantations in the Caribbean, and the resulting Triangle Trade involving Boston, Bostonians started using molasses and brown sugar to sweeten their Boston baked beans and their Boston brown bread. This struck me as deeply hypocritical. It meant that people turned a blind eye to human trafficking and slavery but frowned on free people doing household chores on Sundays. As Haitian-American author Solar Cookers International.

In winter and during cloudy weather, I use a pressure cooker to cook beans. My Presto® pressure cooker is about 20 years old. Two years ago, I bought it some new gaskets and a new handle for the lid. Pressure cookers are great! They save time and energy. Here’s a chart that gives the pressure cooker cooking times for various kinds of beans. Pressure cookers are particularly useful for people who live at high elevations, such as in the Rocky Mountains. That’s because water boils at a lower temperature if the air pressure is low.

Photo by WhyKenFotos

Plant-Based Diet and Vitamin B2 Might Help in Managing Parkinson Disease

Back in November 2009, I wrote a blog post about a study that suggested that a hereditary problem in the metabolism of riboflavin (vitamin B2) and the heavy consumption of red meat could both contribute to the cause of Parkinson disease. The researchers did blood tests for riboflavin for 31 consecutive Parkinson patients who entered their clinic. Every single one of them had abnormally low blood levels of riboflavin. In comparison, only a few of the patients with other neurologic diseases had low riboflavin levels. The Parkinson patients also tended to be heavy consumers of red meat. After the riboflavin deficiency was corrected and the Parkinson patients stopped eating red meat, their motor skills improved dramatically.

I thought that this study was important. It suggested that cheap and generally beneficial interventions could provide significant benefits for people with Parkinson disease. It should have been followed up with larger studies. Keep in mind that Parkinson disease is a major cause of disability among elderly Americans and ranks 14th among causes of death in the United States.

Since then, I’ve seen a few studies in which investigators assess riboflavin status by asking people what they’ve been eating, instead of doing a blood test! This is a big mistake because the Parkinson patients in the 2003 study had riboflavin deficiency even though they were eating normal amounts of riboflavin. Their bodies just weren’t handling the riboflavin efficiently. We need more research to show whether Parkinson patients should routinely be screened for riboflavin deficiency. Of course, if you or a loved one has Parkinson disease, you can just ask for the riboflavin level to be tested. If a patient has a vitamin deficiency, it should be corrected, shouldn’t it?

Another study, published in January of 2011, found that Parkinson patients improved when they switched to a plant-based diet. This came as no surprise to me because simply eating less protein, especially during the daytime, can dramatically improve the patient’s response to L-dopa, which is the drug of choice for treating Parkinson disease.