In my article "Is Sugar Fattening?", I discussed a recent review paper on fructose, by Dr. John Sievenpiper and colleagues (1). It was the most recent of several review papers to conclude that fructose is probably not inherently fattening in humans, but that it can be fattening if it's consumed to excess, due to the added calories. Dr. Sievenpiper and colleagues have also written other papers addressing the metabolic effects of fructose, which appear to be fairly minor unless it's consumed to excess (2, 3, 4, 5). The senior author on these studies is Dr. David Jenkins at McMaster University. David Despain, a science and health writer who publishes a nice blog called Evolving Health, recently interviewed Dr. Sievenpiper about his work.
It's an interesting interview and very timely, due to the recent attention paid to fructose in the popular media. This has mostly been driven by a couple of high-profile individuals-- an issue they discuss in the interview. The interview, recent papers, and sessions at scientific conferences are part of an effort by researchers to push back against some of the less well founded claims that have received widespread attention lately.
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Monday, May 28, 2012
Monday, May 21, 2012
Lower Blood Pressure Naturally
Recently, Chris Kresser published a series on dietary salt (sodium chloride) and health (1). One of the issues he covered is the effect of salt on blood pressure. Most studies have shown a relatively weak relationship between salt intake and blood pressure. My position overall is that we're currently eating a lot more salt than at almost any point in our evolutionary history as a species, so I tend to favor a moderately low salt intake. However, there may be more important factors than salt when it comes to blood pressure, at least in the short term.
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Thursday, May 17, 2012
Beyond Ötzi: European Evolutionary History and its Relevance to Diet. Part III
In previous posts, I reviewed some of the evidence suggesting that human evolution has accelerated rapidly since the development of agriculture (and to some degree, before it). Europeans (and other lineages with a long history of agriculture) carry known genetic adaptations to the Neolithic diet, and there are probably many adaptations that have not yet been identified. In my final post in this series, I'll argue that although we've adapted, the adaptation is probably not complete, and we're left in a sort of genetic limbo between the Paleolithic and Neolithic state.
Recent Genetic Adaptations are Often Crude
It may at first seem strange, but many genes responsible for common genetic disorders show evidence of positive selection. In other words, the genes that cause these disorders were favored by evolution at some point because they presumably provided a survival advantage. For example, the sickle cell anemia gene protects against malaria, but if you inherit two copies of it, you end up with a serious and life-threatening disorder (1). The cystic fibrosis gene may have been selected to protect against one or more infectious diseases, but again if you get two copies of it, quality of life and lifespan are greatly curtailed (2, 3). Familial Mediterranean fever is a very common disorder in Mediterranean populations, involving painful inflammatory attacks of the digestive tract, and sometimes a deadly condition called amyloidosis. It shows evidence of positive selection and probably protected against intestinal disease due to the heightened inflammatory state it confers to the digestive tract (4, 5). Celiac disease, a severe autoimmune reaction to gluten found in some grains, may be a by-product of selection for protection against bacterial infection (6). Phenylketonuria also shows evidence of positive selection (7), and the list goes on. It's clear that a lot of our recent evolution was in response to new disease pressures, likely from increased population density, sendentism, and contact with domestic animals.
Read more »
Recent Genetic Adaptations are Often Crude
It may at first seem strange, but many genes responsible for common genetic disorders show evidence of positive selection. In other words, the genes that cause these disorders were favored by evolution at some point because they presumably provided a survival advantage. For example, the sickle cell anemia gene protects against malaria, but if you inherit two copies of it, you end up with a serious and life-threatening disorder (1). The cystic fibrosis gene may have been selected to protect against one or more infectious diseases, but again if you get two copies of it, quality of life and lifespan are greatly curtailed (2, 3). Familial Mediterranean fever is a very common disorder in Mediterranean populations, involving painful inflammatory attacks of the digestive tract, and sometimes a deadly condition called amyloidosis. It shows evidence of positive selection and probably protected against intestinal disease due to the heightened inflammatory state it confers to the digestive tract (4, 5). Celiac disease, a severe autoimmune reaction to gluten found in some grains, may be a by-product of selection for protection against bacterial infection (6). Phenylketonuria also shows evidence of positive selection (7), and the list goes on. It's clear that a lot of our recent evolution was in response to new disease pressures, likely from increased population density, sendentism, and contact with domestic animals.
Read more »
Saturday, May 5, 2012
Media Appearances
Last October, I participated in a panel discussion organized by the Harvard Food Law Society in Boston. The panel included Drs. Walter Willett, David Ludwig, Robert Lustig, and myself, with Corby Kummer as moderator. Dr. Willett is the chair of the Harvard Department of Nutrition; Dr. Ludwig is a professor of nutrition and pediatrics at Harvard; Dr. Lustig is a professor of clinical pediatrics at UCSF; and Kummer is a food writer and senior editor for The Atlantic.
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Saturday, April 28, 2012
Beyond Ötzi: European Evolutionary History and its Relevance to Diet. Part I
In the previous post, I explained that Otzi descended in large part from early adopters of agriculture in the Middle East or nearby. What I'll explain in further posts is that Otzi was not a genetic anomaly: he was part of a wave of agricultural migrants that washed over Europe thousands of years ago, spreading their genes throughout. Not only that, Otzi represents a halfway point in the evolutionary process that transformed Paleolithic humans into modern humans.
Did Agriculture in Europe Spread by Cultural Transmission or by Population Replacement?
There's a long-standing debate in the anthropology community over how agriculture spread throughout Europe. One camp proposes that agriculture spread by a cultural route, and that European hunter-gatherers simply settldd down and began planting grains. The other camp suggests that European hunter-gatherers were replaced (totally or partially) by waves of agriculturalist immigrants from the Middle East that were culturally and genetically better adapted to the agricultural diet and lifestyle. These are two extreme positions, and I think almost everyone would agree at this point that the truth lies somewhere in between: modern Europeans are a mix of genetic lineages, some of which originate from the earliest Middle Eastern agriculturalists who expanded into Europe, and some of which originate from indigenous hunter-gatherer groups including a small contribution from neanderthals. We know that modern-day Europeans are not simply Paleolithic mammoth eaters who reluctantly settled down and began farming.
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Did Agriculture in Europe Spread by Cultural Transmission or by Population Replacement?
There's a long-standing debate in the anthropology community over how agriculture spread throughout Europe. One camp proposes that agriculture spread by a cultural route, and that European hunter-gatherers simply settldd down and began planting grains. The other camp suggests that European hunter-gatherers were replaced (totally or partially) by waves of agriculturalist immigrants from the Middle East that were culturally and genetically better adapted to the agricultural diet and lifestyle. These are two extreme positions, and I think almost everyone would agree at this point that the truth lies somewhere in between: modern Europeans are a mix of genetic lineages, some of which originate from the earliest Middle Eastern agriculturalists who expanded into Europe, and some of which originate from indigenous hunter-gatherer groups including a small contribution from neanderthals. We know that modern-day Europeans are not simply Paleolithic mammoth eaters who reluctantly settled down and began farming.
Read more »
Tuesday, April 24, 2012
Lessons From Ötzi, the Tyrolean Ice Man. Part III
There are two reasons why I chose this time to write about Otzi. The first is that I've been looking for a good excuse to revisit human evolutionary history, particularly that of Europeans, and what it does and doesn't tell us about the "optimal" human diet. The second is that Otzi's full genome was sequenced and described in a recent issue of Nature Communications (1). A "genome" is the full complement of genes an organism carries. So what that means is that researchers have sequenced almost all of his genes.
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Tuesday, April 17, 2012
Lessons From Ötzi, the Tyrolean Ice Man. Part II
Otzi's Diet
Otzi's digestive tract contains the remains of three meals. They were composed of cooked grains (wheat bread and wheat grains), meat, roots, fruit and seeds (1, 2). The meat came from three different animals-- chamois, red deer and ibex. The "wheat" was actually not what we would think of as modern wheat, but an ancestral variety called einkorn.
Isotope analysis indicates that Otzi's habitual diet was primarily centered around plant foods, likely heavily dependent on grains but also incorporating a variety of other plants (3). He died in the spring with a belly full of einkorn wheat. Since wheat is harvested in the fall, this suggests that his culture stored grain and was dependent on it for most if not all of the year. However, he also clearly ate meat and used leather made from his prey. Researchers are still debating the quantity of meat in his diet, but it was probably secondary to grains and other plant foods. It isn't known whether or not he consumed dairy.
Read more »
Otzi's digestive tract contains the remains of three meals. They were composed of cooked grains (wheat bread and wheat grains), meat, roots, fruit and seeds (1, 2). The meat came from three different animals-- chamois, red deer and ibex. The "wheat" was actually not what we would think of as modern wheat, but an ancestral variety called einkorn.
Isotope analysis indicates that Otzi's habitual diet was primarily centered around plant foods, likely heavily dependent on grains but also incorporating a variety of other plants (3). He died in the spring with a belly full of einkorn wheat. Since wheat is harvested in the fall, this suggests that his culture stored grain and was dependent on it for most if not all of the year. However, he also clearly ate meat and used leather made from his prey. Researchers are still debating the quantity of meat in his diet, but it was probably secondary to grains and other plant foods. It isn't known whether or not he consumed dairy.
Read more »
Monday, April 16, 2012
Exercise and Food Intake
The New York Times just published an article reviewing some of the recent research on exercise, food intake and food reward, titled "Does Exercise Make You Overeat?". I was planning to write about this at some point, but I don't know when I'd be able to get around to it, and the NYT article is a fair treatment of the subject, so I'll just point you to the article.
Basically, burning calories through exercise causes some people to eat more, but not everyone does, and a few people actually eat less. Alex Hutchinson discussed this point recently on his blog (1). Part of it depends on how much fat you carry-- if you're already lean, the body is more likely to increase hunger because it very much dislikes going too low in body fat. Most overweight/obese people do not totally make up for the calories they burn through exercise by eating more, so they lose fat. There is a lot of individual variability here. The average obese person won't lose a substantial amount of fat through exercise alone. However, everyone knows someone who lost 50+ pounds through exercise alone, and the controlled trials support that it happens in a minority of people. On the other side of the spectrum, I have a friend who gained fat while training for a marathon, and lost it afterward.
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Basically, burning calories through exercise causes some people to eat more, but not everyone does, and a few people actually eat less. Alex Hutchinson discussed this point recently on his blog (1). Part of it depends on how much fat you carry-- if you're already lean, the body is more likely to increase hunger because it very much dislikes going too low in body fat. Most overweight/obese people do not totally make up for the calories they burn through exercise by eating more, so they lose fat. There is a lot of individual variability here. The average obese person won't lose a substantial amount of fat through exercise alone. However, everyone knows someone who lost 50+ pounds through exercise alone, and the controlled trials support that it happens in a minority of people. On the other side of the spectrum, I have a friend who gained fat while training for a marathon, and lost it afterward.
Read more »
Sunday, April 15, 2012
Next Primal Chef Event Sunday 5/20
Gil Butler has been working on a television show called Primal Chef, where he invites local chefs to make creative dishes from a list of Paleo ingredients, in a designated amount of time. The format is reminiscent of Iron Chef. The food is judged afterward by figures in the Paleo community. Robb Wolf was a judge on the first episode.
Gil has invited me to be a judge on the next show, along with Sara Fragoso and Dr. Tim Gerstmar. The next day, Sunday April 20th, Gil is organizing a catered Primal Chef event in Seattle, with Paleo dinner, speakers, entertainment, prizes, and a screening of part of Paleo Chef episode 1. You can read the details and sign up here. I won't be speaking because I don't have time to put together another talk right now, but I will be attending the event.
Gil has invited me to be a judge on the next show, along with Sara Fragoso and Dr. Tim Gerstmar. The next day, Sunday April 20th, Gil is organizing a catered Primal Chef event in Seattle, with Paleo dinner, speakers, entertainment, prizes, and a screening of part of Paleo Chef episode 1. You can read the details and sign up here. I won't be speaking because I don't have time to put together another talk right now, but I will be attending the event.
Tuesday, April 10, 2012
Lessons From Ötzi, the Tyrolean Ice Man. Part I
Otzi is Europe's oldest natural human mummy, and as such, he's an important window into the history of the human species in Europe. His genome has been sequenced, and it offers us clues about the genetic history of modern Europeans.
Otzi's Story
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Friday, April 6, 2012
Global Meat Production, 1961-2009
Total global meat production per person has steadily increased from 0.13 lbs per day in 1961 to 0.29 lbs per day in 2009*, a 120 percent increase over the last half century (currently in the US, average meat consumption is about half a pound per day). Since meat consumption in the US and Europe has only increased modestly over time, this change mostly reflects greatly increased meat consumption over the last half century in developing countries** in Asia, Africa and South America. In 1961, it's likely that most of the 0.13 pounds per day of meat was consumed in affluent countries such as the US, with not much consumed elsewhere (with some exceptions). Historically, meat has always been expensive relative to other food sources in agricultural societies, so it's eaten by those who can afford it.
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Monday, April 2, 2012
Eocene Diet Follow-up
Now that WHS readers around the globe have adopted the Eocene Diet and are losing weight at an alarming rate, it's time to explain the post a little more. First, credit where credit is due: Melissa McEwen made a similar argument in her 2011 AHS talk, where she rolled out the "Cambrian Explosion Diet", which beats the Eocene Diet by about 470 million years. It was probably in the back of my head somewhere when I came up with the idea.
April Fools day is good for a laugh, but humor often has a grain of truth in it. In this case, the post was a jumping off point for discussing human evolution and what it has to say about the "optimal" human diet, if such a thing exists. Here's a preview: evolution is a continuous process that has shaped our ancestors' genomes for every generation since the beginning of life. It didn't end with the Paleolithic, in fact it accelerated, and most of us today carry meaningful adaptations to the Neolithic diet and lifestyle.
Read more »
April Fools day is good for a laugh, but humor often has a grain of truth in it. In this case, the post was a jumping off point for discussing human evolution and what it has to say about the "optimal" human diet, if such a thing exists. Here's a preview: evolution is a continuous process that has shaped our ancestors' genomes for every generation since the beginning of life. It didn't end with the Paleolithic, in fact it accelerated, and most of us today carry meaningful adaptations to the Neolithic diet and lifestyle.
Read more »
Sunday, April 1, 2012
The Eocene Diet
65 million years ago, a massive asteroid slammed into the Yucatan peninsula, creating a giant dust cloud that contributed to the extinction of terrestrial dinosaurs. In the resulting re-adjustment of global ecosystems, a new plant tissue evolved, which paved the way for the eventual appearance of humans: fruit. Fruit represents a finely crafted symbiosis between plants and animals, in which the plant provides a nourishing morsel, and the animal disperses the plant's seeds inside a packet of rich fertilizer.
Fruit was such a powerful selective pressure that mammals quickly evolved to exploit it more effectively, developing adaptations for life in the forest canopy. One result of this was the rapid emergence of primates, carrying physical, digestive and metabolic adaptations for the acquisition and consumption of fruit and leaves. Primates also continued eating insects, a vestige of our early mammalian heritage.
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Fruit was such a powerful selective pressure that mammals quickly evolved to exploit it more effectively, developing adaptations for life in the forest canopy. One result of this was the rapid emergence of primates, carrying physical, digestive and metabolic adaptations for the acquisition and consumption of fruit and leaves. Primates also continued eating insects, a vestige of our early mammalian heritage.
Read more »
Tuesday, March 27, 2012
Onward
In upcoming posts, I plan to pursue two main themes. The first is a more comprehensive exploration of what determines eating behavior in humans, the neurobiology behind it, and the real world implications of this research. The reward and palatability value of food are major factors, but there are others, and I've spent enough time focusing on them for the time being. Also, the discussions revolving around food reward seem to be devolving into something that resembles team sports, and I've had my fill.
The second topic I'm going to touch on is human evolutionary history, including amazing recent insights from the field of human genetics. These findings have implications for the nutrition and health of modern humans.
I look forward to exploring these topics, and others, with all of you in the coming months.
The second topic I'm going to touch on is human evolutionary history, including amazing recent insights from the field of human genetics. These findings have implications for the nutrition and health of modern humans.
I look forward to exploring these topics, and others, with all of you in the coming months.
Monday, March 26, 2012
Recent Media Appearances
Men's Health interviewed and quoted me in an article titled "Reprogram Your Metabolism", written by Lou Schuler. Part of the article was related to the food reward concept. I'm glad to see the idea gradually reaching the mainstream.
Boing Boing recently covered an article by Dr. Hisham Ziauddeen and colleagues in Nature Reviews Neuroscience that questioned the idea that common obesity represents food addiction-- an idea that I often encounter in my reading. Maggie Koerth-Baker asked me if I wanted to respond. I sent her a response explaining that I agree with the authors' conclusions and I also doubt obesity is food addiction per se, as I have explained in the past, although a subset of obese people can be addicted to food. I explained that the conclusions of the paper are consistent with the idea that food reward influences fat mass. You can find my explanation here.
Boing Boing recently covered an article by Dr. Hisham Ziauddeen and colleagues in Nature Reviews Neuroscience that questioned the idea that common obesity represents food addiction-- an idea that I often encounter in my reading. Maggie Koerth-Baker asked me if I wanted to respond. I sent her a response explaining that I agree with the authors' conclusions and I also doubt obesity is food addiction per se, as I have explained in the past, although a subset of obese people can be addicted to food. I explained that the conclusions of the paper are consistent with the idea that food reward influences fat mass. You can find my explanation here.
Thursday, March 22, 2012
Food Reward: Approaching a Scientific Consensus
Review papers provide a bird's-eye view of a field from the perspective of experts. Recent review papers show that many obesity researchers are converging on a model for the development of obesity that includes excessive food reward*, in addition to other factors such as physical inactivity, behavioral traits, and alterations in the function of the hypothalamus (a key brain region for the regulation of body fatness). Take for example the four new review papers I posted recently by obesity and reward researchers:
Read more »
Read more »
Monday, March 19, 2012
Speaking at AHS12
I'll be giving a 40 minute presentation at the Ancestral Health Symposium this summer titled "Digestive Health, Inflammation and the Metabolic Syndrome". Here's the abstract:
What determines this? Emerging research suggests that one factor is digestive health, including the bacterial ecosystem inside each person's digestive tract, and the integrity of the gut barrier. I'll review some of this research in my talk, and leave the audience with actionable information for maintaining gastrointestinal and metabolic health. Most of this information will not have been covered on this blog.
The Ancestral Health Symposium will be from August 9-12 at Harvard Law School in Boston, presented in conjunction with the Harvard Food Law society. Tickets are currently available-- get them before they sell out! Last year, they went fast.
See you there!
Excessive fat mass is an important contributor to the metabolic syndrome, but at the same level of body fatness, some people are metabolically normal while others are extremely impaired. Even among obese people, most of whom have the metabolic syndrome, about 20 percent are metabolically normal, with normal fasting insulin and insulin sensitivity, normal blood pressure, normal circulating inflammatory markers, and normal blood lipids.The “metabolic syndrome” is a cluster of health problems including abdominal obesity, insulin resistance, low-grade inflammation, high blood pressure and blood lipid abnormalities that currently affects one third of American adults. It is the quintessential modern metabolic disorder and a major risk factor for diabetes, heart disease and certain cancers. This talk will explore emerging links between diet, gut flora, digestive health and the development of the metabolic syndrome. The audience will learn about factors that may help maintain digestive and metabolic health for themselves and the next generation.
What determines this? Emerging research suggests that one factor is digestive health, including the bacterial ecosystem inside each person's digestive tract, and the integrity of the gut barrier. I'll review some of this research in my talk, and leave the audience with actionable information for maintaining gastrointestinal and metabolic health. Most of this information will not have been covered on this blog.
The Ancestral Health Symposium will be from August 9-12 at Harvard Law School in Boston, presented in conjunction with the Harvard Food Law society. Tickets are currently available-- get them before they sell out! Last year, they went fast.
See you there!
Saturday, March 17, 2012
Qnexa, the Latest Obesity Drug
There are very few obesity drugs currently approved for use in the US-- not because effective drugs don't exist, but because the FDA has judged that the side effects of existing drugs are unacceptable.
Although ultimately I believe the most satisfying resolution to the obesity epidemic will not come from drugs, drugs offer us a window intn the biological processes that underlie obesity and fat loss. Along those lines, here's a quote from a review paper on obesity drugs that I think is particularly enlightening (1):
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Although ultimately I believe the most satisfying resolution to the obesity epidemic will not come from drugs, drugs offer us a window intn the biological processes that underlie obesity and fat loss. Along those lines, here's a quote from a review paper on obesity drugs that I think is particularly enlightening (1):
Read more »
Friday, March 9, 2012
Boing!
I just had a featured article published on Boing Boing, "Seduced by Food: Obesity and the Human Brain". Boing Boing is the most popular blog on the Internet, with over 5 million unique visitors per month, and it's also one of my favorite haunts, so it was really exciting for me to be invited to submit an article. For comparison, Whole Health Source had about 72,000 unique visitors last month (200,000+ hits).
The article is a concise review of the food reward concept, and how it relates to the current obesity epidemic. Concise compared to all the writing I've done on this blog, anyway. I put a lot of work into making the article cohesive and understandable for a somewhat general audience, and I think it's much more effective at explaining the concept than the scattered blog posts I've published here. I hope it will clear up some of the confusion about food reward. I don't know what's up with the image they decided to use at the top.
Many thanks to Mark Frauenfelder, Maggie Koerth-Baker, and Rob Beschizza for the opportunity to publish on Boing Boing, as well as their comments on the draft versions!
For those who have arrived at Whole Health Source for the first time via Boing Boing, welcome! Have a look around. The "labels" menu on the sidebar is a good place to start-- you can browse by topic.
The article is a concise review of the food reward concept, and how it relates to the current obesity epidemic. Concise compared to all the writing I've done on this blog, anyway. I put a lot of work into making the article cohesive and understandable for a somewhat general audience, and I think it's much more effective at explaining the concept than the scattered blog posts I've published here. I hope it will clear up some of the confusion about food reward. I don't know what's up with the image they decided to use at the top.
Many thanks to Mark Frauenfelder, Maggie Koerth-Baker, and Rob Beschizza for the opportunity to publish on Boing Boing, as well as their comments on the draft versions!
For those who have arrived at Whole Health Source for the first time via Boing Boing, welcome! Have a look around. The "labels" menu on the sidebar is a good place to start-- you can browse by topic.
Saturday, March 3, 2012
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