Hyperphagia

One of the things I didn't mention in the last post is that Americans are eating more calories than ever before. According to Centers for Disease Control NHANES data, in 2000, men ate about 160 more calories per day, and women ate about 340 more than in 1971. That's a change of 7% and 22%, respectively. The extra calories come almost exclusively from refined grains, with the largest single contribution coming from white wheat flour (correction: the largest single contribution comes from corn sweeteners, followed by white wheat flour).

Some people will see those data and decide the increase in calories is the explanation for the expanding American waistline. I don't think that's incorrect, but I do think it misses the point. The relevant question is "why are we eating more calories now than we were in 1971?"

We weren't exactly starving in 1971. And average energy expenditure, if anything, has actually increased. So why are we eating more? I believe that our increased food intake, or hyperphagia, is the result of metabolic disturbances, rather than the cause of them.

Humans, like all animals, have a sophisticated system of hormones and brain regions whose function is to maintain a proper energy balance. Part of the system's job is to keep fat mass at an appropriate level. With a properly functioning system, feedback loops inhibit hunger once fat mass has reached a certain level, and also increase resting metabolic rate to burn excess calories. If the system is working properly, it's very difficult to gain weight. There have been a number of overfeeding studies in which subjects have consumed huge amounts of excess calories. Some people gain weight, many don't.

The fact that fat mass is hormonally regulated can be easily seen in other mammals. When was the last time you saw a fat squirrel in the springtime? When was the last time you saw a thin squirrel in the fall? These events are regulated by hormones. A squirrel in captivity will put on weight in the fall, even if its daily food intake is not changed.

A key hormone in this process is leptin. Leptin levels are proportional to fat mass, and serve to inhibit hunger and eating behaviors. Under normal conditions, the more fat tissue a person has, the more leptin they will produce, and the less they will eat until the fat mass has reached the body's preferred 'set-point'. The problem is that overweight Westerners are almost invariably leptin-resistant, meaning their body doesn't respond to the signal to stop eating!

Leptin resistance leads to hyperphagia, overweight and the metabolic syndrome (a common cluster of symptoms that implies profound metabolic disturbance). It typically precedes insulin resistance during the downward slide towards metabolic syndrome.

I suspect that wheat, sugar and perhaps other processed foods cause hyperphagia. It's the same thing you see when wheat is first introduced to a culture, even if it's replacing another refined carbohydrate. I believe hyperphagia is secondary to a disturbed metabolism. There's something about the combination of refined wheat, sugar, processed vegetable oils and other industrial foods that reached a critical mass in the mid-70s. The shift in diet composition disturbed our normal hormonal profile (even more than it was already disturbed), and sent us into a tailspin of excessive eating and unprecedented weight gain.

How the Media Contribute to our Health Problems

The New York Times just published an article called "The Overflowing American Dinner Plate", in which they describe changes in the American diet since 1970, the period during which the obesity rate doubled. Bill Marsh used USDA estimates of food consumption from 1970 to 2006. Predictably, he focuses on fat consumption, and writes that it has increased by 59% in the same time period.

The problem is, we aren't eating any more fat than we were in 1970. The US Centers for Disease Control NHANES surveys show that total fat consumption has remained the same since 1971, and has decreased as a percentage of calories. I've been playing around with the USDA data for months now, and I can tell you that Marsh misinterpreted it in a bad way. Here are the raw data, for anyone who's interested. They're in easy-to-use Excel spreadsheets. I highly recommend poking around them if you're interested.

The reason Marsh was confused by the USDA data is they have a column in the "fats" spreadsheet called "total fat". But "total fat" is a misnomer, because it doesn't include fats from meat and milk. What it reflects is primarily concentrated fats like vegetable oil, butter, lard and shortening. That's what has increased by 59%, and it's almost exclusively due to increased use of industrially processed vegetable oil (butter and lard have decreased). Total fat has remained the same because we now eat low-fat cuts of meat and low-fat dairy products to make up for it!

Another problem with the article is it only shows percent changes in consumption of different foods, rather than absolute amounts. This obscures some really meaningful information. For example, grain consumption is up a whopping 42%. That is the largest single food group change if you exclude the misinterpreted fat data. Corn is up 188%, rice 170%, wheat 21%. But in absolute amounts, the increase in wheat consumption is larger than corn or rice! That's because baseline wheat consumption dwarfed corn and rice. We don't get that information from the data presented in the article, due to the format.

So now that I've deconstructed the data, let's see what the three biggest changes in the American diet from 1970 to 2006 actually are:

• We're eating far more grains, especially white wheat flour
  
• We're eating more added sweeteners, especially high-fructose corn syrup
• Animal fats from milk and meat have been replaced by processed vegetable oils
  

Wheat + sugar + processed vegetable oil = fat and unhealthy. Sounds familiar, doesn't it? This NYT article is just another example of how superficial journalism can really obscure the truth.

Power Walking to Weight Loss Success

Veolia has experienced super success at weight loss. After being obese for thirty years, she decided to make a major lifestyle change in her late 40's. She went from 400 pounds to 138 pounds. She lost all this weight in just 20 months. She did this by going from being inactive to walking at least six days a week.

Her favorite snack food between meals are bulk nuts such as walnuts, brazil nuts and almonds. These are high calorie foods but full of good fats. Walnuts especially are very high in omega 3.

She says; "I have so much energy and my stamina is incredible for a 54-year-old. And to me, the best part is that I did it all by myself without spending money, having surgery, taking pills or trying the latest diet fad." She's gone from a size 32 to a size 2, and was recently featured on the "Today" show.

See her incredible before and after photos and story here.

Life Expectancy and Growth of Paleolithic vs. Neolithic Humans

If paleolithic people were healthier than us due to their hunter-gatherer lifestyle, why did they have a shorter life expectancy than we do today? I was just reminded by Scott over at Modern Forager about some data on paleolithic (pre-agriculture) vs. neolithic (post-agriculture) life expectancy and growth characteristics. Here's a link to the table, which is derived from an article in the text Paleopathology at the Origins of Agriculture.

The reason the table is so interesting is it allows us to ask the right question. Instead of "why did paleolithic people have a shorter life expectancy than we do today?", we should ask "how did the life expectancy of paleolithic people compare to that of pre-industrial neolithic people?" That's what will allow us to tease the effects of lifestyle apart from the effects of modern medicine.

The data come from age estimates of skeletons from various archaeological sites representing a variety of time periods in the Mediterranean region. Paleolithic skeletons indicated a life expectancy of 35.4 years for men and 30.0 years for women, which includes a high rate of infant mortality. This is consistent with data from the Inuit that I posted a while back (life expectancy excluding infant mortality = 43.5 years). With modest fluctuations, the life expectancy of humans in this Mediterranean region remained similar from paleolithic times until the last century. I suspect the paleolithic people died most often from warfare, accidents and infectious disease, while the neolithic people died mostly from chronic disease, and infectious diseases that evolved along with the domestication of animals (zoonotic diseases). But I'm just speculating based on what I know about modern populations, so you can take that at face value.

The most interesting part of the table is actually not the life expectancy data. It also contains numbers for average stature and pelvic inlet depth. These are both markers of nutritional status during development. Pelvic inlet depth is a measure of the size of the pelvic canal through which a baby would pass during birth. It can be measured in men and women, but obviously its implications for birth only apply to women. As you can see in the table, stature and pelvic inlet depth declined quite a bit with the adoption of agriculture, and still have not reached paleolithic levels to this day.

The idea that a grain-based diet interferes with normal skeletal development isn't new. It's well-accepted in the field of archaeology that the adoption of grains coincided with a shortening of stature, thinner bones and crooked, cavity-ridden teeth. This fact is so well accepted that these sorts of skeletal changes are sometimes used as evidence that grains were adopted in a particular region historically. Weston Price saw similar changes in the populations he studied, as they transitioned from traditional diets to processed-food diets rich in white wheat flour, sweets and other processed foods.

The change in pelvic inlet depth is also very telling. Modern childbirth is so difficult, it makes you wonder why our bodies have evolved to make it so drawn-out and lethal. Without the aid of modern medicine, many of the women who now get C-sections and other birth interventions would not make it. My feeling is that we didn't evolve to make childbirth so lethal. It's more difficult in modern times, at least partially because we have a narrower pelvic inlet than our ancestors. Another thing Weston Price commented on was the relative ease of childbirth in many of the traditional societies he visited. Here's an exerpt from Nutrition and Physical Degeneration:

A similar impressive comment was made to me by Dr. Romig, the superintendent of the government hospital for Eskimos and Indians at Anchorage, Alaska. He stated that in his thirty-six years among the Eskimos, he had never been able to arrive in time to see a normal birth by a primitive Eskimo woman. But conditions have changed materially with the new generation of Eskimo girls, born after their parents began to use foods of modern civilization. Many of them are carried to his hospital after they had been in labor for several days. One Eskimo woman who had married twice, her last husband being a white man, reported to Dr. Romig and myself that she had given birth to twenty-six children and that several of them had been born during the night and that she had not bothered to waken her husband, but had introduced him to the new baby in the morning.

Now that's what I call fertility!

Liquids and Mushies

Thanks for all your support guys.

I got a real telling off from Wendy at WLS Group. She told me to drink iced fluids for 24 hours and then liquids and soup until I see her on Sunday as I am totally jeopardising my band by being way too tight and sick so much. She said it was very dangerous to have stayed in that position and I should have got in touch with her immediately I noticed the amount of HMS'ing.

I have been very good. I did what she said all day Friday & Saturday. Sunday was a bit awful. TB was having some serious stress and I needed to be a chocolate eating partner with her, so I ingested my body weight in minstrels and had several glasses of vino too. Yesterday I had a little mashed potato and also muesli bar as well as yogurts etc.

Today I have been good too. I had a muesli bar with some milk for breakfast. For lunch I had a little bit of spaghetti that was left in the can after DS had spaghetti on toast for his lunch.

I have just consumed some nice biscuits soaked in coffee and that's probably going to me for the day. I might have a yogurt for dinner though.

I cant do liquids for a week. But puree and soft diet I can do. its a half way house.

Hunting

Like 99.9% of the world's population, I am mostly dependent on agriculture for my food. It's fun to pretend sometimes though. I enjoy foraging for berries, mushrooms and nuts.

Last week, I went crabbing in the San Juan islands. We caught our limit of meaty dungeness crabs every day we put the pots out. If we had been working harder at it (and it was legal), we could easily have caught enough crabs to feed ourselves completely. We cooked them fresh and ate some the same day. We extracted the meat from the rest, and made an amazing crab bisque using a stock made from the shells, and lots of cream.

Here's a "hunting photo". No smiling allowed; I had to look tough...

Composition of the Hunter-Gatherer Diet

I bumped into a fascinating paper today by Dr. Loren Cordain titled "Plant-Animal Subsistence Ratios and Macronutrient Estimations in Worldwide Hunter-Gatherer Diets." Published in 2000 in the American Journal of Clinical Nutrition, the paper estimates the food sources and macronutrient intakes of historical hunter-gatherers based on data from 229 different groups. Based on the available data, these groups did not suffer from the diseases of civilization. This is typical of hunter-gatherers.

Initial data came from the massive Ethnographic Atlas by Dr. George P. Murdock, and was analyzed further by Cordain and his collaborators. Cordain is a professor at Colorado State University, and a longtime proponent of paleolithic diets for health. He has written extensively about the detrimental effects of grains and other modern foods. Here's his website.

The researchers broke food down into three categories: hunted animal foods, fished animal foods and gathered foods. "Gathered foods" are primarily plants, but include some animal foods as well:

Although in the present analysis we assumed that gathering would only include plant foods, Murdock indicated that gathering activities could also include the collection of small land fauna (insects, invertebrates, small mammals, amphibians, and reptiles); therefore, the compiled data may overestimate the relative contribution of gathered plant foods in the average hunter-gatherer diet.

There are a number of striking things about the data once you sum them up. First of all, diet composition varied widely. Many groups were almost totally carnivorous, with 46 getting over 85% of their calories from hunted foods. However, not a single group out of 229 was vegetarian or vegan. No group got less than 15% of their calories from hunted foods, and only 2 of 229 groups ate 76-85% of their calories from gathered foods (don't forget, "gathered foods" also includes small animals). On average, the hunter-gatherer groups analyzed got about 70% of their calories from hunted foods. I think this makes a very strong case that meat-heavy omnivory is our preferred ecological niche. However, it also shows that we can thrive on a plant-rich diet containing modest amounts of quality animal foods.

The paper also discusses the nature of the plant foods hunter-gatherers ate. Although they ate a wide variety of plants occasionally, more typically they relied on a small number of staple foods with a high energy density. There's a table in the paper that lists the most commonly eaten plant foods. "Vegetables" are notably underrepresented. The most commonly eaten plant foods are fruit, underground storage organs (tubers, roots, corms, bulbs), nuts and other seeds. Leaves and other low-calorie plant parts were used much less frequently.

The paper also gets into the macronutrient composition of hunter-gatherer diets. I think his methods have a tendency to de-emphasize fat consumption. He writes that

...the most plausible... percentages of total energy from the macronutrients would be 19-35% for protein, 22-40% for carbohydrate, and 28-58% for fat.

He derives these numbers from projections based on the average composition of plant foods, and the whole-body composition of representative animal foods (includes organs, marrow, blood etc., which they typically ate). However, as he notes in his paper, humans can't tolerate more than about 35% of calories from protein before developing "rabbit starvation". Therefore, carnivorous groups must have been getting at least 65% of their calories from fat, and probably more in many cases. This agrees with data from the Inuit, who typically ate roughly 80% of their calories in the form of fat.

Second, he generalizes using data from animals with "typical" body composition, whereas hunter-gatherers often actively sought the fattest animals they could find. For example, he cites squirrels as having a body fat percentage of 2%, but anyone who has seen a squirrel in the fall knows that they can be much fatter than that. Older, larger ungulates (deer, elk, etc.) were preferentially sought out by many groups due to their high body fat percentage. It's an obvious strategy because more fat = more calories. Natives on the North American Pacific coast rendered fat from fish, seals, bears and whales, using it liberally in their food. Here's an excerpt from The Northwest Coast by James Swan, who spent three years living among the natives of the Washington coast in the 1850s:

About a month after my return from the treaty, a whale was washed ashore on the beach between Toke's Point and Gray's Harbor and all the Indians about the Bay went to get their share... The Indians were camped near by out of the reach of the tide, and were all very busy on my arrival securing the blubber either to carry home to their lodges or boiling it out on the spot, provided they happened to have bladders or barrels to put the oil in. Those who were trying out [rendering] the blubber cut it into strips about two inches wide, one and a half inches thick, and a foot long. These strips were then thrown into a kettle of boiling water, and as the grease tried out it was skimmed off with clam shells and thrown into a tub to cool and settle. It was then carefully skimmed off again and put into the barrels or bladders for use. After the strips of blubber have been boiled, they are hung up in the smoke to dry and are then eaten. I have tried this sort of food but must confess that, like crow meat, "I didn't hanker arter it".

Despite the bias against fat consumption, I was very impressed by the paper overall. I think it presents a good, simple model for eating well: eat whole foods that are similar to those that hunter-gatherers would have eaten, including at least 20% of calories from high-quality animal sources. Organs are mandatory, vegetables are not. Sorry, Grandma.