The Problem With the Paleo Diet Argument

Our epidemics of dietary disease have prompted a great deal of research into what humans are meant to eat for optimal health. In 1985, an influential article was published proposing that our chronic diseases stem from a disconnect between what our bodies ate while evolving during the Stone Age (about 2 million years ago) and what we’re stuffing our face with today. The proposal advocated for a return towards a hunter-gatherer type diet of lean meat, fruits, vegetables, and nuts.

It’s reasonable to assume our nutritional requirements were established in the prehistoric past. However, the question of which prehistoric past we should emulate remains. Why just the last 2 million? We’ve been evolving for about 20 million years since our common great ape ancestor, during which our nutrient requirements and digestive physiology were set down. Therefore our hunter-gatherer days at the tail end probably had little effect. What were we eating for the first 90% of our evolution? What the rest of the great apes ended up eating—95 percent or more plants.

This may explain why we’re so susceptible to heart disease. For most of human evolution, cholesterol may have been virtually absent from the diet. No bacon, butter, or trans fats; and massive amounts of fiber, which pulls cholesterol from the body. This could have been a problem since our body needs a certain amount of cholesterol, but our bodies evolve not only to make cholesterol, but also to preserve it and  recycle it.

If we think of the human body as a cholesterol-conserving machine, then plop it into the modern world of bacon, eggs, cheese, chicken, pork, and pastry; it’s no wonder artery-clogging heart disease is our #1 cause of death. What used to be adaptive for 90% of our evolution—holding on to cholesterol at all costs since we weren’t getting much in our diet—is today maladaptive, a liability leading to the clogging of our arteries. Our bodies just can’t handle it.

As the editor-in-chief of the American Journal of Cardiology noted 25 years ago, no matter how much fat and cholesterol carnivores eat, they do not develop atherosclerosis. We can feed a dog 500 eggs worth of cholesterol and they just wag their tail; a dog’s body is used to eating and getting rid of excess cholesterol. Conversely, within months a fraction of that cholesterol can start clogging the arteries of animals adapted to eating a more plant-based diet.

Even if our bodies were designed by natural selection to eat mostly fruit, greens and seeds for 90% of our evolution, why didn’t we better adapt to meat-eating in the last 10%, during the Paleolithic? We’ve had nearly 2 million years to get used to all that extra saturated fat and cholesterol. If a lifetime of eating like that clogs up nearly everyone’s arteries, why didn’t the genes of those who got heart attacks die off and get replaced by those that could live to a ripe old age with clean arteries regardless of what they ate?

Because most didn’t survive into old age. Most prehistoric peoples didn’t live long enough to get heart attacks. When the average life expectancy is 25 years old, then the genes that get passed along are those that can live to reproductive age by any means necessary, and that means not dying of starvation. The more calories in food, the better. Eating lots of bone marrow and brains, human or otherwise, would have a selective advantage (as would discovering a time machine stash of Twinkies for that matter!). If we only have to live long enough to get our kids to puberty to pass along our genes, then we don’t have to evolve any protections against the ravages of chronic disease.

To find a population nearly free of chronic disease in old age, we don’t have to go back a million years. In the 20th century, networks of missionary hospitals in rural Africa found coronary artery disease virtually absent, and not just heart disease, but high blood pressure, stroke, diabetes, common cancers, and more. In a sense, these populations in rural China and Africa were eating the type of diet we’ve been eating for 90% of the last 20 million years, a diet almost exclusively of plant foods.

How do we know it was their diet and not something else? In the 25 year update to their original paleo paper, the authors tried to clarify that they did not then and do not now propose that people adopt a particular diet just based on what our ancient ancestors ate. Dietary recommendations must be put to the test. That’s why the pioneering research from Pritikin, Ornish, and Esselstyn is so important, showing that plant-based diets can not only stop heart disease but have been proven to reverse it in the majority of patients. Indeed, it’s the only diet that ever has.

In health,
Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live year-in-review presentations Uprooting the Leading Causes of DeathMore Than an Apple a DayFrom Table to Able, and Food as Medicine.

The Real Paleo Diet
Eliminating 90% of Heart Disease Risk
Never Too Late to Start Eating Healthier



Lesa D
Past Member 2 months ago

my problem with Paleo? meat...

thank you Dr Michael...

Jetana A
Jetana Aabout a year ago

Most proponents of the so-called paleo diet are people grabbing an excuse to eat lots of meat.

Ruth S
Ruth Sabout a year ago


Siyus Copetallus
Siyus Copetallus2 years ago

Thank you for sharing.

Darlene Buckingham

Gerald again use common sense. What takes more resources to get to the table - meat or vegetables? How much water does it take to keep slaughterhouses sanitary is another point to look at. Also what happens in a drought? The majority of the North American supply for grass fed meat is now being shipped in from New Zealand as they have the most grasslands. Why is grass fed meat so expensive if it is so inexpensive to produce according to you? It is a good idea to research any faux meats to make sure they are not using GMOs. This is no doubt a controversial subject but if a person cares about animals, the environment and their health they will find a way to eat the best foods from the best agricultural practices.

Gerald L.
Gerald L2 years ago

Brian there is a problem with Vegan Poopaganda! Do you ever think critically? Stating I takes 2500 Gallons of Water to convert grass to ONE Lb. Of BeeF is pretty smelly.

Multiply an average 1400 Lb. Market Steer X 2500 Gallons of Water = 3, 500, 000 Gallons of Water. Divide by a 20,000 Gallon DOT 111 Railway Tanker used to carry liquids. It would take 175 Railway Tanker Loads of Water to grow on 1400 Lb. Market Steer.

You would need Rail lines into Ranches to nourish the herds of cattle. Truth be told Brian grass grazed cattle would be Un-affordable. The Canadian Beef Research Council estimates it takes EIGHT Gallons of Water.

Why the deceit Brian? Is it moral and ethical to deceive the public. Some Vegas claim it takes upwards of 24,000 Gallons of Water per Lb. of grass to beef conversion.

Brian please do the math @ 24000 gallons Multiplied by an average 1400 Lb Market Steer and please share how many 20000 DOT 111 Railway Tankers would be needed.

I smell a biased deceitful attempt at manipulation. Tell me Brian how can a Self Propelled Ruminant nourished by the Sunshine Rainfall Grass Cycle be more expensive than the Giant Metal Behemoths needed to grow Soybeans for your FAUX Meats.

I am still waiting for your Report on the Full Cycle Co$t$ of a Faux Burger and all its Ingredients trucked in and processed all over the Continent.

Still waiting Brian.

Gerald L.
Gerald L2 years ago

@ 5:19pm CT 25MAR2016. Brian s Cookie Cutter view of human civilization that lives in multiple zones from Jungle Desert Equatorial to Artic Tundra. Noooo meat you heretics as Brian fosters HIS philosophy. Fire Brian for cooking heat light. Local Ojibway pounded out pots from native copper. Other tribes used pit cooking under hot coals or fire. Roasting meat on a stick. Technology has advanced Brian although he holds to a narrow view.

WHO | Household air pollution and health‎
Around 3 billion people still cook and heat their homes using solid fuels (i.e. wood, crop wastes, charcoal, coal and dung) in open fires and leaky stoves. ... The risk for women is higher, due to their role in food preparation. ... The lack of access to electricity for at least 1.2 billion people (many of whom then use kerosene ...

Brian F. The fact that humans must cook their meat unlike true carnivores proves we are not meant to eat meat. True carnivores have short intestines, which allows meat to pass through quickly. Humans have long intestines, which forces meat to take too long to pass through. Humans also lack the kind of teeth that true carnivores have to slice into meat. A vegetarian diet is the true diet that humans should be eating to maintain optimum health. A vegetarian diet significantly reduces your chances of being obese, and suffering from diseases such as heart disease. cancer, and others. Also, animals do

Muff-Anne York-Haley

Selfish, cruel, unsustainable diet!!

Marija K.
Marija K2 years ago

Brian F,
Just thanks for the exhaustive info that you provided.. Never cared much to look it up myself, as the ethicalness(my primary concern) of any diet is evident, which I insinuated by saying that there is nothing to argue about ethics.

Marija K.
Marija K2 years ago

''Just because some humans choose to eat just plants doesn't make them herbivores. They can still eat meat.'' -- Well, I've suspected earlier that we might have got to arguing over semantics of 'herbivore' and 'omnivore'. But you have STILL argued against *veganism* with 'human omnivorousness', which is worthless. It makes no sense to counter-argue humans eating 100% plant diet with the fact that humans CAN eat plants and animals.
''The omnivorous diet is on a spectrum from only plants to only meat and every quantity between.''--Semantics. As I said, you're still arguing against *veganism*.
''I brought the word "unethical" up once not repeatedly.'' -- You said ''ethics are subjective'' out of nowhere in your very first reply to me.
''I never said I wanted a private message, I was only making a statement that you defended Brian's statement and are defensive about humans being omnivorous.'' --Well, sorry about that assumption, I really see no other point in pointing out that I 'defended Brian's statement'. I noticed an inconsistency in your reply to Brian and brought it up.