The Natural Human Diet

NF-Nov15 The Problem with the Paleo Diet Argument copy.jpg

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 highlighted in my video The Problem With the Paleo Diet Argument 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 last 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.

For more on the absence of Western diseases in plant-based rural populations, see for example:

I've touched on "paleo" diets in the past:

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:

Image Credit: Nathan Rupert / Flickr

Original Link

The Natural Human Diet

NF-Nov15 The Problem with the Paleo Diet Argument copy.jpg

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 highlighted in my video The Problem With the Paleo Diet Argument 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 last 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.

For more on the absence of Western diseases in plant-based rural populations, see for example:

I've touched on "paleo" diets in the past:

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:

Image Credit: Nathan Rupert / Flickr

Original Link

Dr. Greger’s 2015 Live Year-in-Review Presentation

Food as Medicine

View my new live presentation here: Food as Medicine: Preventing and Treating the Most Dreaded Diseases with Diet

Every year I scour the world's scholarly literature on clinical nutrition, pulling together what I find to be the most interesting, practical, and groundbreaking science on how to best feed ourselves and our families. I start with the thousands of papers published annually on nutrition (27,000 this year--a new record!) and, thanks to a crack team of volunteers (and now staff!), I'm able to whittle those down (to a mere 8,000 this year). They are then downloaded, categorized, read, analyzed, and churned into the few hundred short videos. This allows me to post new videos and articles every day, year-round, to NutritionFacts.org. This certainly makes the site unique. There's no other science-based source for free daily updates on the latest discoveries in nutrition. The problem is that the amount of information can be overwhelming.

Currently I have more than a thousand videos covering 1,931 nutrition topics. Where do you even begin? Many have expressed their appreciation for the breadth of material, but asked that I try to distill it into a coherent summary of how best to use diet to prevent and treat chronic disease. I took this feedback to heart and in 2012 developed Uprooting the Leading Causes of Death, which explored the role diet may play in preventing, arresting, and even reversing our top 15 killers. Not only did it rise to become one of the Top 10 Most Popular Videos of 2012, it remains my single most viewed video to date, watched over a million times (NutritionFacts.org is now up to more than 1.5 million hits a month!).

In 2013 I developed the sequel, More Than an Apple a Day, in which I explored the role diet could play in treating some of our most common conditions. I presented it around the country and it ended up #1 on our Top 10 Most Popular Videos of 2013. Then in 2014 I premiered the sequel-sequel, From Table to Able, in which I explored the role diet could play in treating some of our most disabling diseases, landing #1 on our Top 10 Most Popular Videos of 2014.

Every year I wonder how I'm going to top the year before. Knowing how popular these live presentations can be and hearing all the stories from folks about what a powerful impact they can have on people's lives, I put my all into this new 2015 one. I spent more time putting together this presentation than any other in my life. It took me an entire month, and when you see it I think you'll appreciate why.

This year, I'm honored to bring you Food as Medicine, in which I go through our most dreaded diseases--but that's not even the best part! I'm really proud of what I put together for the ending. I spend the last 20 minutes or so (starting at 56:22) going through a thought experiment that I'm hoping everyone will find compelling. I think it may be my best presentation ever. You be the judge.

You can watch it at no cost online, but it is also available on DVD through my website or on Amazon. If you want to share copies with others, I have a five for $40 special (enter coupon code 5FOR40FAM). All proceeds from the sales of all my books, DVDs, downloads, and presentations go to the 501c3 nonprofit charity that keeps NutritionFacts.org free for all, for all time. If you want to support this initiative to educate millions about eradicating dietary diseases, please consider making a donation.

After you've watched the new presentation, make sure you're subscribed to get my video updates daily, weekly, or monthly to stay on top of all the latest.

-Michael Greger

Original Link