fat

I read an advanced copy of Why Women Need Fat when I was moving and because things were so hectic, I didn't have time to review it before it was released. I haven't heard that much about it though, except for this interesting interview with one of the authors in Salon. It's co-authored by Dr. William D. Lassek and anthropologist Steven Gaulin. 

It's an interesting book, but it's slightly hampered by the fact that their theories and prescriptions are both quite complicated and controversial. Unlike most other diet books, the authors are not claiming that their diet will make you thin. In fact, they emphasize the importance of body fat to women and the unique factors that influence women's health risks. 

So the book opens up a can of worms because it addresses fat in women, as well as evolutionary psychology. Talk about hot-button topics! But they are indeed strange bedfellows and it's interesting to see the synergy between them both. 

The first chapter of the book addresses similar territory as Good Calories, Bad Calories with a history of how dietary fat, particularly saturated fat, became unfairly demonized by Ancel Keys and friends. But there is more discussion regarding the rise of polyunsaturated fats, which were erroneously believed to be a healthy alternative to the naughty animal fats.

Ironically, the next chapter starts with a discussion of Denmark, where women eat more saturated fat than Americans, yet they have lower rates of obesity and heart disease. It's ironic because last year Denmark stupidly started taxing saturated fat to discourage consumption. But here the book diverges a bit from Taubes because they note that actually sugar is a smaller share of calorie consumption in the US than it was in 1961 and overall we eat about the same amount of sugar as the Danes. They also note that the idea that carbohydrates are the culprit also doesn't make sense if you compare countries like Japan to the US. 

Instead the authors look towards what they call the single biggest change in the American diet in the past forty years:the enormous increase in vegetable oils high in polyunsaturated fat, particularly the omega-6 variety. We consume more soybean oil than any other country in the world. That's been great for industrial monoculture farmers and food corporations, but hasn't seem to have done much good for our health. To add insult to injury, many of the oils introduced into the diet were not only mostly omega-6 fat, but also were partially hydrogenated, which created trans fats. Trans fats are pretty much unanimous considered extremely detrimental to health even in small amounts (as an aside, on the issue of women and fat, I think it's criminal that the Girl Scouts teach our young women to sell cookies that still contain trans-fats.) 

Most food corporations have switched away from trans fats, but polyunsaturated oils are still considered healthy by many, including the USDA. Even people who aren't cooking with the oils are getting generous servings in nearly everything, from salad dressings to baked goods. 

But here is where I get skeptical- the authors say that omega-6 could be a cause of weight increases in the population because it's converted into arachidonic acid. But if arachidonic acid is the issue, it makes the later dietary recommendations in the book seem suspicious, because most animal products are rich in arachidonic acid. And many of the studies they cite simply show that people who are overweight have higher blood levels of omega-6, but that doesn't tell us that the omega-6 was the cause. Considering that omega-6 fats are added to almost every processed food, you could blame it on an assortment of things from the palatability of the food (The End of Overeating) to wheat (Wheat Belly). However, it is interesting that it seems that some studies show that the weight gain from those eating diets very high in omega-6 is disproportionately distributed in the waist. 

So how do they think this all works? They say that omega-6 makes us heavier by producing certain types of signaling molecules called eicosanoids, which promote the growth and development of fatty tissue and fat storage. Another factor is that such eicosanoids make white blood cells more active, which increases inflammation. 

Much like Wheat Belly did with wheat, they also frame their villain as an addictive drug, since the body can make marijuana-like molecules out of arachidonic acid called endocannabinoids. Yes, cannabinoids, like marijuana, and the authors claim that it can stimulate the appetite similarly. But then it goes back to the fact that if this were true, wouldn't other foods rich in arachidonic acid cause similar problems? And those foods include things like meat and eggs.

I think they erroneously dismiss Kressler's book by focusing on sugar, when in reality Kressler also pegged processed fat as a villain as well, just one that works in synergy with other components of processed foods, which seems more likely to be the issue with these omega-6 rich vegetable oils than arachidonic acid. 

Either way, through the studies that show omega-6 can cause weight gain disproportionately in the waist seem quite tentative, it is an interesting thing to think about, especially since several chapters focus on the importance of fat distribution. 

These are the chapters bring in evolutionary psychology, which discuss controversial theories on the functional attractiveness of the waist-hip-ratio. Anthropologists have surveyed hundreds of cultures across the world and one of the few measures of attractiveness that seems fairly constant is that men seem to prefer a waist to hip ratio between .68 and .72 (even blind men). Does this actually mean anything evolutionarily? Is there an adaptive reason men find this attractive? 

Human women are unusual in the first place by how fatty we are. A slim woman can have a body fat percentage of 30%. A chimpanzee female has a body fat percentage around 5%. In this metric, we are closer to whales or polar bears than other primates. The fat is usually concentrated in the buttocks, breasts, thighs, and hips. Studies have shown that the average man finds fat in these areas particularly attractive. 

What is this fat for? Interestingly, women tend to lose the fat in these areas as they have children even if they gain weight overall and have plenty to eat. The lose correlates to the number of children a woman has. Lassek and Gaulin found that most of this fat seemed to be lost during nursing. During this period, an average woman eats less than she needs and instead seems to use up this lower body fat. 

Why is this happening? It doesn't make sense that women would be just using this fat to give the baby extra calories, because otherwise they would eat more.

Turns out that there is something in this fat tissue that the developing infant brain really needs. The human infant brain is unusually large and it's not just hungry for calories, it's hungry for fat. In particular it's hungry for DHA, the immediately usable form of omega-3 fatty acids that has been found to be crucial for optimal infant brain development. 

Unfortunately, the diets of most American women only provide half of the DHA that a pregnant woman and her infant need. Another type of omega-3 fatty acid, Alpha Linoleic Acid (ALA) can be converted to DHA, but this conversion varies (though interestingly pregnant women have upregulated conversion and the placenta also has the ability to push DHA "uphill" creating a higher level of DHA in the infant's blood than in the mother's) and can be down-regulated by excessive omega-6 in the diet.

The authors theorize that towards the end of the pregnancy, a woman eats less in order to foster utilization of her own fat tissues that are rich in DHA. The fat in the hips, buttocks, and thighs has more DHA than the fat in other parts of the body. This DHA has been accumulated over many years, starting in infancy.

I read a frightening Facebook conversation I witnessed in which a girl was bragging about how her thighs didn't touch, another girl mentioned that she was so mad that her thighs kept touching even though she had gotten "thin.". Like this question on Paleohacks, many women find that weight seems to come off everywhere but the thigh/buttock/hip region where the gluteofemoral fat lies. This can be frustrating in a culture where slimness everywhere but the breasts is desired. But seen in the light of the importance of this fat, it makes sense why the body resists mobilizing this fat when weight is lost and many women can't achieve the thinness they want in this region without getting so thin everywhere else that they are dangerously overweight or their ribs are showing. These women don't have "lipodystrophy," they are normal women whose bodies are trying to remain functional in a world where our body ideals have become dysfunctional.

The authors own research that suggests that women with more of this important fat have smarter children.

They also attempt to find a reason why men seem to like small waists, despite the fact that they are associated with low BMI, which is associated with poor fertility. Women aren't just fatter than other apes, we have the riskiest childbirth, a consequences of our infant's oversize brains. The first birth is always the most risky because the birth canal is un-stretched. The authors present data that shows that smaller-waisted women have smaller babies (even though they eat more during pregnancy) and thus easier first-time childbirth. So for most of evolutionary history, it would seem more beneficial for a woman to be neither too heavy, nor too thin, with the fat concentrated in the buttocks, hips, and thighs.

But once the first baby expands the birth canal, a woman can afford to have a bigger baby. And biologically, bigger babies might not be good for a first-time mother, but if they make it out of the birth canal they are more likely to survive and thrive. So the authors theorize that the reason many women find that they are starting to get bigger around the waist after they have their first child is that the extra weight will benefit the next child.

The mechanism they use to explain this is leptin, which plays many important roles in fertility. It also tells a woman's hypothalamus how much body fat she has and then uses this as a guide to tell the body how much of the nutrients that come from meals that she should store and how much should circulate in the blood. When a woman has higher body fat, her hypothalamus "tells her cells to pay less attention to her insulin's request to save." Higher fat stores mean more fat, sugar, and amino acids in the blood. Nutrients are more available to the placenta in the first place and the brain is more amenable to requests for more. But too much fat can be a bad thing at a certain point. Heavier mothers are more likely to suffer from preeclampsia, which could be because the placental hormones that "request" more nutrients are overactive and then the cells of the placenta burrow deeper into the wall of the womb to access the biggest arteries, causing an immune-system reaction. Interestingly, it's more likely if it's the first time a mother is carrying a particular man's child and becomes less likely as she bears more children by the same man.

So Lassek and Gaulin theorize that a larger waist signals to a man that a woman might already have a child to take care of and has also already used up some of her valuable DHA-rich fat. Another controversial idea they introduce is that even a child-less woman will gain weight as she ages because she is likely to have fewer children, so in order to increase the likelihood of genes being passed on, it's more important for any children she has to survive because she might not get another chance. So her waist accumulates fat in order to have a bigger baby, even if that means increasing the risk of the childbirth. 

But even if some weight-gain is desirable, things seem to have gone haywire recently. Women gain this weight much earlier and are overall much heavier than their foremothers. They also suggest it's possible that the low amount of DHA in our diets might be responsible for higher overall fat accumulation, reasoning that if a woman gets half as much DHA from her diet as another woman, she will have half as much DHA in each pound of fat. So in order for her body to accumulate an optimum total amount of DHA, she will need to store more fat. I didn't feel the evidence was very strong for this theory, mostly the observation that  women are thinner in countries with high-DHA diets, but it is very interesting.

The next part of the book is devoted to the idea of achieving "a natural healthy weight." It examines several studies that show that being slightly overweight (BMI of 25-29) seems to actually be healthy for women (but not for men). A lot of this stuff is similar to what was in the Healthy At Every Size book I read.

Another reason why older women might tend to be overweight, was that in the past this represented a protection against infections like tuberculosis, which killed many thin women. This may be because fat confers more active white blood cells. Luckily, estrogen protects women from some of the downsides of having more fat. Higher estrogen means higher HDL, which is good cholesterol. In general, women are seven times less likely than men to die of coronary disease before age sixty-five (I suspect personally that iron levels play a role here too). There is a downside, in that higher levels of estrogen seem to be related to higher risk of breast cancer, but that seems to mainly hold true for obese, not overweight, women. Overweight women are also more likely to develop type 2 diabetes. The authors recommend that women can follow a high omega-3, low omega-6 diet to help mitigate this risk regardless of a woman's weight.

Some other interesting facts are mentioned, such as the fact that heavier women are less likely to break their hips. Hip breakage is a common cause of death in the elderly. However, heavier women are more likely to have arthritis. 

But overall, they say that the focus on heaviness itself is probably misguided, because it's where the fat is distributed that matters. Large waist size in particular seems to be associated with health risks. Interestingly, in the 1990s, about half of women in the overweight group had waist sizes in the unhealthy over-35-inch range. Today roughly three out of four do and 1/7 "normal" weight women also have this problem. 

Unfortunately, dieting just doesn't work for most people and in fact people are often worse off after they try diets. Lassek and Gaulin say that calorie restriction makes women miserable and often ends up raising their set points. Instead, they say women should try to return to more human-appropriate diet, with special attention to consuming more omega-3 and less omega-6. 

They have a section on reducing omega-6, which mainly focus on fried and processed foods that contain soybean or corn oil. They also recommend being careful about poultry, though weirdly they don't mention pork. They also have a whole section on potatoes as hidden sources of omega-6, but all the potato-foods with high-omega-6 levels are fried or cooked with high omega-6 oils, so it's not actually the potatoes that are the problem. 

In order to boost omega-3, they recommend grass-fed meat, wild fish, and/or fish oil/algal DHA supplements. Annoyingly, they don't mention some potential caveats to supplementing such as "fishy burps" and general gastrointestinal upset. It's also definitely not a paleo diet, because they recommend you eat wheat, since it doesn't have much omega-6. They also recommend canola oil, which I personally view with skepticism, particularly if the goal is to return to the diet and thus the weights of our foremothers. I wasn't such a fan of this section of the book. It's clear the authors know much about anthropology and medicine, but not that much about food. I'm glad they are promoting grass-fed meat, but it honestly doesn't have that much DHA. You would have to eat 4.6 lbs of grass-fed beef to get the recommended 1.6 grams of DHA.

And then the rest of the book is about finding your realistic "natural weight," which is the weight your body will gradually shift to once you adjust your diet. This takes into account age and bone structure. Unfortunately, it also involves four steps of calculation. And there are also some eating tips, which are kind of easier said than done:

1. Eat until you are satisfied and then stop
2. Eat breakfast and avoid snacks after dinner
3. Try to have smaller portions
4. Chose nuts and fruit for snacks
5. Limit commercial beverages
6. Get regular exercise
7. Reduce the amount of processed food in your diet

The interesting thing is that nuts have tons of omega-6. Shouldn't they be bad then? In the end I applaudan approach that recognizes that body fat plays a unique role in women and discourages the eating-disorder-like behavior and unrealism of traditional dieting. Unfortunately, while I think most bloggers I read have a healthy attitude, I see ridiculous bro-science about women's weight like this post on "Top 10 ways to get Skinny Fat." Besides the obvious fact that there are plenty of women who do those things who have ideal or very low body fat, I thought the choice of "scare" picture was telling:

Seriously? That is not a picture of an unhealthy "skinny fat" woman. In fact, there are plenty of women who eat the "magic" paleo diet that many of these sites tout and have much more body fat than that. Not that I think that's a bad thing. Those women are probably much healthier than some of the health bloggers I've seen who are so thin that it really worries me.

That's one limitation to the book. Despite having a more realistic attitude about weight than most books, it still seems to be primarily targeted towards people who want to lose. But the theory the book contains implies that not having DHA-rich fat stores would be bad as well. I personally believe it's possible even for women who are skinny to rebuild healthy curves. I was very very thin when I was raw vegan and over the years of eating fertility-supporting foods like butter and fish roe and improving my digestion I have laid down more fat tissue (and quite a bit of muscle) on my chest, thighs, and buttocks without increasing my waist size very much. I've received similar comments from other women. Is it any surprise that Marilyn Monroe ate a similar diet?

Also, let's get real here. Just like it's absolutely hilarious that writers can quote studies that show foragers are healthy in one breath, and demonize foods that make up most of their diet in another, I think it's weird to tout a very modernized female ideal as part of a "paleo" approach considering that forager women simply don't look like that and that art from the actual Paleolithic seems to portray a culture in which fertility-related fat was venerated.

I also enjoyed the evolutionary theory for the role of body fat in women. But I think their practical advice seems awkward and limited by lack of food expertise. I also think the evidence that omega-6 is responsible for obesity is somewhat limited, as laid out by a recent post by Stephen Guyenet, though I definitely agree that it can cause other problems. And maybe the association only holds up for women?

 One thing I will miss in NYC are the fantastic restaurants. I particularly applaud the trend of restaurants that go whole hog and use real bone stocks and animal fat in their dishes. Obviously, these restaurants are pretty vegetarian-unfriendly and have been a little controversial. 

Unvegetarian, unapologetic animal eater restaurants

The Momofuku restaurants were instrumental in jumpstarting the pork belly and rich broth trends. There are several restaurants in the group (and one in Sydney and Toronto now). There are plenty of vegetables on the menu, but often they are drenched in delicious pork fat. One of the best dishes is chanterelles with bone marrow, a luxurious and fatty combination, but only available seasonally. The various traditional Southern Hams make an excellent appetizing and the offal dishes are not to be missed. 

I think Salt & Fat, which is in my neighborhood in Queens, is a little inspired by Momofuku and also be Williamsburg's excellent Traif. Their appetizer is bacon-fat popcorn, which is amazing. I recommend the yellowtail tartare, the delicious ribs with homemade BBQ sauce, the incredibly rich salads with all kinds of animal fat bits, and the hearty oxtail terrine. 

I'm mentioned Takashi like a zillion times, but that's because it's a temple of delicious meat and they do offal so well that it's the perfect place to try crazy things. I LOVE the sweet breads. They seem kind of scary at first, but they melt in your mouth. The liver is also not to be missed. I don't usually like liver that much, but their liver is marinated so perfectly that it's delicious raw. I've never had anything I disliked on the menu and I think I've eaten almost everything on it. 

I really like Fatty Cue because they use lots of delicious animal fats with dashes of fish sauce for flavor. The dishes are salty, fatty, tangy, and spicy. I particularly recommend the coriander bacon.

Because it's Brooklyn, they actually probably have some real vegetarian dishes at Palo Santo, but the chef here cooks everything else with real house-made animal fats and stocks. The cuisine spans many countries in Latin America and uses ingredients from many local farms. 

Vegetarian Restaurants I actually eat at: 

Saravanaa Bhavan is one of my favorite places for Indian food. I love idlis, which are steamed fermented rice/lentil cakes served with a spicy soup called sambar.

Rockin Raw makes an excellent raw-vegan cinnamon roll that's gluten, soy, and nut-free. When I crave a sweet treat, I go here.

Occasionally I get a weird craving for falafel. Organic Avenue's raw falafel is oil-free and gluten-free. To me, it tastes as good as the real thing.

Bacon Branzino @ Salt & Fat

Chole Island (Creative Commons)

Yesterday I read an interesting paper in Human Brain Evolution: The Influence of Freshwater and Marine Food Resources. I have some issues with this book, which is a collection of papers, but there is some great information. One of the interesting chapters is Lessons from Shore-Based Hunter-Gatherer Diets in East Africa. Some of it is available as this paper Milk in the island of Chole [Tanzania] is high in lauric, myristic, arachidonic and docosahexaenoic acids, and low in linoleic acid reconstructed diet of infants born to our ancestors living in tropical coastal regions.

Chole is an island in Tanzania, home to a population that is a mixture of various peoples from the African inlands, the legacy of the Arab slave trade. The paper describes their diet as being coconut, marine fish (which they boil), vegetables, fruits (oranges, mango, and banana), and an occasional flying fox. I do not believe this description is completely accurate. The researchers were looking for a culture that eats close to the "paleolithic diet" as described by Cordain: lean meat, fruits, and vegetables. Unfortunately, this culture does not exist, which leads to the bizarre paradox of using cultures that eat either high-carb, high-fat, or both to bolster the idea that this diet is the best for humans. Later in the paper they use this hypothesis and the data from the people of Chole, to estimate a paleo diet that is nothing like the diet of the people of Chole. They published a separate paper on this, which Don at Primal Wisdom has blogged about. I am more skeptical than Don, as I don't believe the diet we evolved on would be close to the upper limit of the % calories of protein that is the estimate for the max capacity of the liver to convert excess nitrogen to urea (35%)*.  Their estimated ratios are suspiciously close to the zone diet...

I'm not a fan of the method of deciding what is healthy and then trying to fit the ancestral evidence into it, which seems to be their main method. They repeatedly say that staple carbohydrates weren't part of Paleolithic diets, only citing Cordain, who has no evidence for this. I notice they don't hawk low-fat much explicitly, despite their estimated paleolithic diets, since they are working with data from people eating high-fat. But I digress, because I really just wanted to talk about breast milk here and their breast milk data is great. They have data from the people of Chole, three groups of fish-eating controls (Kerewe, Nyakius, and Nyiramba), four groups from the inland (Hadza- who are foragers, Maasai, Songo, and Iraqiw), plus they presented historical data from Dar Es Salaam and several Western countries. 

Here we can see the people from Chole very high amounts of two particular saturated fatty acids: lauric and myristic. The Kerewe have similar levels of myristic and the people of Dar es Salaam have similar levels of lauric. Chole and Dar es Salaam are located in a costal region where palm and coconut trees are abundant. Other places where coconut is eaten frequently like Dominica and Surinam, also had high levels of lauric acid. What about myristic? The authors explain that the Kerewe do not consume coconut, but have a high carbohydrate intake from ugali (a corn/wheat porridge) and muhoho (cassava). They do not explain why other cultures eating a high-carbohydrate diet don't have similar levels or why the levels in the Chole are so high. 

Despite it not being mentioned in the paper, the Chole do eat plenty of carbohydrates (though in what amounts remains to be studied). This book mentions that they grow potatoes, corn, millet, squash, cassava, and rice. This ethnography on storytelling also mentions these crops. Here is a woman in New Scientist, pounding rice: 

Did their culture change all the sudden? Why aren't the authors mentioning these foods? Out of the blue they say that "carbohydrates cause the highest increase in total cholesterol/HDL cholesterol (Mensink et al., 2003), suggesting an atherosclerosis-promoting effect of the carbohydrate-rich diet of Kerewe." I can't find any evidence that the Kerewe suffer from this condition and considering how similar their diet is to the Kitavans, I suspect that they don't have it. 

Apparently you can get lauric and myristic acid from coconut, but there is evidence that carbohydrate-rich diets raise the milk content of medium chain fatty acids as well by de novo synthesis from glucose. I will have to look at the papers cited, but perhaps this mechanism is suppressed somehow in people with excessive linoleic acid in their diets, which would explain why the people of Palestine have low levels, for example. The authors not that in their data set, lauric acid correlates inversely with linoleic acid and positively with DHA and AA. 

As for why this carb to medium chain fatty acid mechanism exists, we get no speculation, but another citation to Cordain for the idea that carbohydrate-rich diets were not part of our dietary habits.

No matter how they got there, medium chain fatty acids in breastmilk seem to be beneficial.  They are easily absorbable as energy (especially since babies are in ketosis no matter what their mother's diet is), and they have antiviral and antimicrobial properties. 

When were coconuts introduced into the human diet? The fact that much of the Paleolithic coastline is underwater and decomposition tends to be rapid in hot humid climates means the fossil evidence is scant. But a silicified coconut fruit was found in the Chinchilla sands in Southern Queensland from 2 million years ago, which suggests that they were widely dispersed even then, since the current origin of the coconut based on genetic studies seems to be East Africa (where humans may have evolved into our modern form) or the American West coast. 

The breastmilk of Chole is very low in linoleic acid and pretty high in DHA, though not as high as in the Kerewe. This is not surprising considered their diet, which is rich in seafood.

How much exogenous DHA is needed for infants for optimum brain and eye development is currently under debate. The authors of this book believe that the DHA needs in infants require the mother to consume seafood, or at least large amounts of DHA-rich organs like brain (though insects also are a source of DHA too). I'm not sure this is true myself, but would be curious to see the Hadza (inland foragers) compared to the people of Chole.

Hilariously, the breast milk of Chole VIOLATES formula recommendations of the Commission Directive of 1991 (I hope the recent ones have been revised), which recommend that lauric and myristic fatty acids be no more than 15%. 90% of Chole samples violate this recommendation. They also are too high in Arachidonic acid, which has a bad rap, but it is important for infant brain development and there is evidence its negative effects only occur when omega-3 is low. There is also evidence that infants cannot create enough of the needed AA from precursors. 

The unfortunate fact is that often guidelines for synthetic substitutes like formulas are based on "normal" women. And considering the health of the normal people in the US, normal might be a bad thing. This paper points out that current data is taken from populations with high levels of degenerative diseases of civilization. According to nutritionism-ists like Marion Nestle, you need a bunch of studies to show DHA is needed in formula. Studies aren't the be-all and end-all, particularly if they are based on populations that are not living optimally. If I were forced to use formula, I'd rather have it be based on the breastmilk of a healthy population than wait decades for a bunch of studies and continue basing it on a bad dataset. 

While I disagree with some assertions in this paper, as they seem to be bent by preconceived notions about macronutrients and the Paleolithic, it is very interesting and points to the need for more studies on populations like that on Chole before vegetable oil is introduced. 

*I am working on a different post on this issue. 

 Last year I met a girl who was trying the paleo diet and complaining she "felt weird" and her stomach hurt. I asked her what she was eating and it turns out she was eating 5 tablespoons of coconut oil for breakfast! I told her that wasn't food, that it was an ingredient you can use to make foods or a supplement and that maybe she should try eating food. Later she said she felt better. 

I guess there is some impression among certain people that because I and others don't think fat is *bad* that you should drown yourself in it. As far as I'm concerned it's a far cry from a certain Paleo cookbook that advocates trimming fat off of GRASS FED meat, throwing away the fat that is leftover from cooking grass-fed meat,  and avoiding grass-fed "fatty cuts" like shanks to eating a pound of bacon for breakfast with a side of heavy-cream flavored coconut milk. Let's be honest: I don't eat that way. I cook with tallow that I save from the whole goats and lambs I buy, I certainly don't ever throw away any "fatty" cut, and sometimes I use some ghee, bacon, butter, or coconut milk as ingredients. I go through a pound of bacon a month, mostly because of my boyfriend, and maybe a can of coconut milk every two weeks and a pack of Pasture Butter a month. I never make any "paleo" desserts anymore and I don't eat very much dairy unless it's well-fermented and raw. Heavy cream makes my digestive system into sludge. I do eat some grains: I find my stomach is happiest when I include some rice in my diet every few days or so. 

I suspect someone who is more athletic or who doesn't have IBS might tolerate more fat. But this is my personal "sweet spot." I do have experience doing almost-vegan paleo: starches, veggies, fruits, no added fats, and only shellfish as protein. Perhaps it could be perfected, but I found that my keratosis really was itchy and red. I also felt more depressed and had bloating. If I tried it again I would probably use some coconut milk with carrot juice or something in an attempt to get vitamin A, but maybe my body isn't suited for it because of my genetics and health problems. Maybe it's also different for people in different life-stages. I'm a woman of reproductive age, so it's possible my need for certain vitamins is higher. 

I also would note that food sensitivities don't care about the paleolithic. It's very possible to be allergic or sensitive to a host of "paleo" foods from types of meat, to nuts, to eggs, to shellfish. I am personally quite sensitive to vegetables like broccoli, onions, and cauliflower. Honestly, they do a number on my stomach worse than any grain. I think people get caught up in the "paleo" paradigm thinking that because we evolved with foods like it, it must be good. But modern food sensitivities don't discriminate. I find that interestingly my stomach feels much better if I get starch from regular potatoes rather than sweet potatoes. The latter is considered "more paleo" though that stems from botanical ignorance. 

Either way, I don't really follow an orthodox "paleo" diet either, though I do use what I learn about the paleolithic to think about what I eat. I think there is tons of room for experimentation, particularly as the evidence for starch consumption in the paleolithic becomes stronger and stronger.

I don't think there is much room for combining "paleo" with various religious philosophies and I'm a little dismayed that Chinese medicine has somehow crept in and become tolerated. I think if I blogged about how I use Christianity to tell me what to eat I'd get about a million angry comments. Remember, the mechanisms behind Chinese medicine are scientifically implausible and even if a few tiny studies show that Chinese medicine works, it's not because of supernatural forces like conveniently undetectable "energy fields" operating outside of the forces of biology, chemistry, and physics. I know plenty of people who follow a "paleo" diet that is compatible with their religion, such as kosher or halal folks, but they don't claim that their diet is somehow better because of it or that it explains their diet's success. 

There has got to be a scientific explanation or I'm just not buying it...

Addendum:

It seems that some people were upset with the idea that I was attacking alternative medicine in the last post. No, I was attacking scientifically implausible theories of food being integrated by the ancestral food community. It's because people don't want to believe there are both unverifiable supernatural beliefs AND beliefs worth investigating to find out whether or not they have some natural basis or benefit.

Acupuncture, for example, is a system worth investigating because of the possibility that the ancient literature refers to real physiological processes, as Chris Kessler points out, and not energy fields (scientists have looked for these energy fields and NOT found them).

The idea that some Chinese roommates once told me that going to bed with my hair wet would cause demonic possession leading to pneumonia made me wonder if perhaps people in rural China did get sick from chills, but otherwise it is a supernatural belief.

Likewise, I am a huge fan of traditional Chinese foods, but when my waitress at my favorite restaurant in Flushing tells me I eat too much fatty "Yang" food and will get acne and clog my blood (that would be awesome since I have a mild form of hemophilia) I think it's worth investigating, but most of the time Chinese traditional food beliefs have been investigated, they have found to be incorrect or vast simplifications. I'm impressed at the latter, but I won't be basing my food choices on whether or not foods are "Yin" or "Yang." I suspect these beliefs have very little to do with Taoism anyway, as they were probably added on as Taoism blended with local folk religions.

Some of these folk beliefs lead to some absurdly unhealthy behaviors. I know Thai people who believe it's good to wash down beef, which is a "hot" food, with Coke, which is a "cold" food. And Chinese people who follow their fried chicken with heavily sugared red date tea because it's "Yin" and replenishes their "Qi." Since these beliefs are not based on real concepts, they are particularly vulnerable to industrialization. 

Religions/folk beliefs and food: worth investigating and important tools for believers, but not always scientific.