I’m a fat dude. Okay, that’s not actually true. I’m a fit middle-aged man who can probably kick your ass (if you’re asleep, tied down, or in a wheelchair). But I was a fat kid; and once the fat self-image gets in your brain, it never ever goes away, despite the evidence offered by either the mirror or the bench press machine.
As a result of my obsession with my belly fat, I’m always experimenting with diets and workout protocols. (I’m a series of “n of 1” studies, as a colleague likes to quip.) In the past few years, I’ve settled on a workout routine that is full body, high intensity and short duration, and built upon muscle confusion, using my own body weight, and, where applicable, heavy lifting. This, my research suggests, is because of the hormonal changes that such activities elicit, such as initiating a more voluminous flow of HGH. The wider theory underpinning this approach is that that was how our bodies were meant to be exerted.
What does “meant to be” mean in a physiological construct, without invoking a godhead of some kind? It means that those sudden and intense motions that comprise my workout simulate, as best as possible considering the other demands on my time, the lifestyle of our hunter-gather ancestors thousands of years ago.
Why is that important? Because, the theory goes, modern humans have had the same physiology and anatomy for slightly over 200,000 years. Only with the advent of civilization, characterized by the invention of agriculture about 10-12 thousand years ago, did the physical demands on our bodies change. So evolution had optimized our physiologies to be best toned through explosive, full body actions that emulate the chasing of prey, the fleeing from predators, or the foraging for goods.
Okay, then, what about diet? It will come as no surprise that I tend to favour the so-called “paleo” diets, which seek to approximate the hunter-gatherer diet. Paleo diets differ, but most tend to feature hunks of meat and animal fat a couple of times a month (when the hunters strike well), and daily intake of nuts and raw vegetables, which is what most of our ancestors would have subsisted upon. It’s a diet high in soluble and insoluble fibre, and polyunsaturated fats, with sudden and extreme intakes of protein.
In short, my lifestyle mantra tends to be, “Eat lean and green, and workout mean.” (He says while stuffing back another piece of pumpkin pie. Hey, it’s Thanksgiving!)
The evidence for all of this varies. But no one will ever deny that eating mostly fresh nuts and vegetables is good for you. Uncertainly arises around portion size, meal frequency, and the fractional nature of specific meals; for example, what percentage of our diets should be carbohydrates, fats, or proteins?
The evidence is confusing for a lot of reasons. One of them is that it is ethically problematic to conduct randomized controlled trials (RCTs) on populations’ diets for long periods of time. One can conduct brief, laboratory analyses on specific dietary elements (e.g., Vitamin D supplementation), or one can observe so-called “natural experiments” in which two populations who have already chosen to eat in different ways are observed for changes in health. If indeed different physiologies will react differently to different dietary proportions, then RCTs in general will be extremely problematic, as it becomes a nightmare to disentangle causal elements.
All of this is to say that I just listened to a podcast. This one: “Grain Brain: Experts disagree over whether grains are bad for our brains“. And some friends asked me to comment on the science cited in the podcast. What better way to do so than through a blog post?
Now, for those of you too lazy to listen to the episode, it’s an interview with Dr David Perlmutter, who is the author of Grain Brain. It’s a book about how grain is bad for our brains; not just gluten-containing grains, all grains. It’s sort of a follow-up of Dr William Davis’s Wheat Belly, a book that claims that grain intake, especially gluten intake, is at the heart of our obesity epidemic. The podcast had an opposing opinion provided by Dr Carol Greenwood.
As always, it’s important to keep everyone’s biases in mind. Dr Perlmutter wants to sell books. I’m sure he’s motivated by other things, too, but book sales are no doubt prime on his agenda. (As someone who also writes books, I assure you that when I care more about the ideas than the profits, I always find a way to make the book free; Perlmutter also has that option.) Dr Greenwood serves on something called The Healthy Grains Institute, which is an industry-funded…. thing… that purports to offer scientific perspective on the health of a grain-based diet.
As for me, I’m driven by epidemiology (i.e., evidence) and pride myself on my openness to changing my mind if presented with more compelling data. However, even I have my biases. As stated above, I’m partial to explanations that leverage evolution and history, hence my liking for paleo diets. As well, I minimize simple carbohydrates, glutens, and grains in my diet already, and can report feeling more energetic and clear thinking, and having a flatter stomach as a result. But one man’s experience is the lowest form of data; remember that.
Some important facts to note, for those not schooled in nutritional sciences, and for those who haven’t read the cited books or listened to the podcast:
- Carbohydrates are starches. Sugar is the most basic carbohydrate.
- Gluten is a type of protein found mostly in wheat.
- Whole grains contain protein, fibre, fat, and carbohydrates. What is most common in our modern diets are separated or processed grains, which contain usually mostly carbohydrate. White bread, for example, is pretty much sugar, with very small amounts of protein, fibre, or fat.
- Fats come from either plant or animal sources. Animal fats (and coconut) tend to be so-called monounsaturated, while plant fats (oils) are typically polyunsaturated.
- Dr Perlmutter claims that “ancient” diets (i.e., pre-agriculture) consisted of 75% fat, 20% protein, and 5% carbs. This is in contrast to the modern diet, which is 20% protein, 20% fat, and 50-60% carbs.
- He advises advises eating (in moderation) amaranth, buckwheat, rice, millet, quinoa, sorghum, teff and gluten-free oats…. all of which are grains, ironically.
- Some people are allergic to gluten. Most people are not. Some people also claim to be “gluten-sensitive”, though it is unclear what that means.
- People with celiac disease are known to respond well to the removal of gluten from their diets
- The rise of people who claim to respond poorly to gluten, but who nevertheless do not have celiac disease, has resulted in a so-called “epidemic” of people with “non-celiac gluten sensitivity”. It’s important to note that almost all of the instances of this condition are self-reported, meaning that we just don’t know if it’s real.
- A “Mediterranean diet” is one consisting of lots of plant fat (olive oil), appreciable whole grains, legumes, fruits and vegetables, and fish.
So, listening to the podcast, I jotted down some thoughts:
- Perlmutter (and Davis) are not the first people to bring these issues up
- Agreed, inflammation is indeed the cornerstone to many maladies, such as heart disease. But the evidence is unclear on whether it is causal or associative, and how much its contribution is mediated by other factors, including diet, exercise, and genetics.
- While inflammation is strongly associated with disease, it is profoundly uncertain whether inflammation is well associated with diet. (See cited studies at the bottom of this blog post.)
- Perlmutter claims we’ve been on this Earth for 2.5 million years, whereas agriculture has been around for 10,000 years. As noted above, modern humans have been around for about 200 thousand years. The most recent homo erectus bones were dated to around 140,000 years ago, and we don’t want to be comparing ourselves to another species. We know so little about diets prior to 25,000 years that it’s kind of silly to make extrapolations to any period beyond our immediate hunter-gather experiences just prior to agriculture.
- It is indeed well known that fats are an essential part of our diet. My own athletic experience is in the world of fighting and martial arts. Everyone in that world understands the need for a high fat intake, as there is great overlap with the world of bodybuilding. I think the evidence for the need for sufficient fats to maintain proper neurological function is also well established.
- Perlmutter’s claim that 70% of our diet should be fat is… well… surprising. However, I should not be confused. The Inuit diet is around 70% fat, and those people do not report as high rates of diabetes as their southern cousins; though the data in that group is poor. Perlmutter, a neurologist, might be biased toward the 70% number since neurons are in fact 70% fat (and 30% protein). When I look at my own diet, I realize that it is typically very high fat, as well; and I try to model my diet after high-performance athletes (of which I am not one, let’s be clear). I eat a lot of peanut butter, almonds, coconut oil, olive oil, and grape seed oil. The diets of MMA fighters that I’ve read about are quite similar (minus the pumpkin pie, of course). So, upon further reflection, 70% sounds like a reasonable proportion for an active, high performing individual.
- A high fat diet is generally good, but it does not necessarily follow that a low carb diet is better. It might be, but the logic doesn’t require it to be so. Higher fat levels are associated with something called “nitrogen sparing”, which leads to better maintenance of muscle mass. And muscle mass burns more calories simply by existing, therefore resulting in, presumably, less body fat. As well, a lot of ingested fat is needed to maintain and produce Testosterone levels, which in turn are important for muscle development.
- Dr Greenwood’s claims that we have in fact made many strides forward in nutrition (measured in resulting good health) the past few centuries, with a diet nevertheless based on grains, is correct. However it should be noted that the human animal lost a lot of health the with invention of agriculture and the taming of grains. As per one blog with plenty of citations to back up its claims, “A well-known finding is that when humans started farming they became shorter, less robust, and exhibited numerous pathologies. The new foods were apparently not so good for us.” Bioarchaeology is an imprecise and emerging science, but I think it’s fair to say that the advent of agriculture had a net negative effect on individual health, with a great societal positive in terms of total calorie production, which then allowed for more births, care for the sick and injured, etc.
- In fact, one of the great confounding factors affecting these sorts of analyses is that in the hunter-gather milieu, the sick and weak died more commonly, so the resulting survivors appeared healthier. Whereas, post-agriculture societies appear less healthy due to the continued life of its sickest and weakest members. In any case, Dr Greenwood’s observation is more of an economic one than a nutritional one. Recent advances in stature and anti-hunger are the results of increases in wealth in places previously suffering generations of famine and poor crop performance. I think it says little about the innate health benefits (or threats) posed by grains.
- The same is true when using life expectancy as a outcome measure. Improvements in life expectancy for the last few hundred years have very little to do with individuals being healthier, and almost everything to do with investments in maternal and child health. High child mortality rates drag down the average population life expectancies; in general, individuals are not living all that much longer.
- Dr Perlmutter characterized insulin as a “fat storage” hormone. This is not entirely correct. Insulin is an anabolic hormone. And it’s true that carbohydrate intake triggers insulin action. What this means is that insulin catalyses either/both fat storage and/or muscle development. Every gym rat knows that ingesting some simple carbs after an intense resistance session will result in greater muscle growth. This is because the ingested sugar will trigger the insulin which will then do its work to increase build-up of muscle. In absence of the training, insulin will move the excess blood energy contents into fat. So once more a simple idea is complicated by human behaviour: your lifestyle will affect what your body does with the ingested carbohydrate.
- Dr Perlmutter stated that the decade in which people were compelled to eat less fat and more carbohydrate was the same decade in which diabetes rates tripled. I’m not sure which decade he was referring to, or to which population. But we must be on guard for something Epidemiologists call “detection bias.” Assuming his numbers are true, it is entirely possible that improved disease surveillance artifactually detected the increase in disease rates. As well, what he reports is a correlation, not necessarily a causal relationship. The increase in diabetes rates could have been due to, I don’t know, the introduction of high-fructose corn syrup (therefore due to a type of new carb, not to carbs in general), or to a general decrease in physical activity. We just don’t know.
- Fat is also known to increase satiety. A 70% fat diet, as recommended by Dr Perlmutter, results in less hunger, therefore less eating overall. I would not be surprised if people eating mostly fat also end up consuming fewer calories than those eating the traditional 50% carbohydrate diet. What this means is that it may be the satiety of a fat diet that is responsible for less obese people, and not anything innately evil about carbohydrates. I’m not saying this is the case, only pointing out a flaw in the reasoning.
Now, it strikes me that some of the more searchable of the scientific questions concern the role of inflammation in disease, and the role of glutens and grains in providing that inflammation. Here are some of the pertinent studies I found:
- The influence of empirically derived dietary patterns on cognitive function in independent older adults depends on income and education: The NuAge Study — a Western diet results in poorer cognitive function than other cultures’ diets. This might mean that Western reliance on carbs is to blame, but there are so many confounding factors that one cannot make that conclusion. Score a weak point, though, for the anti-grain folks.
- High-fat diets, insulin resistance and declining cognitive function — high fat diet results in cognitive defecit in rats and humans. But this may be gated by insulin resistance. Score a weak point for the pro-grain folks, even though grains are not mentioned in this study.
- Whole-grain consumption is associated with a reduced risk of noncardiovascular, noncancer death attributed to inflammatory diseases in the Iowa Women’s Health Study –Eating whole grains actually reduced inflammation in American women. Score a strong point for the pro-grain people.
- Effects of Wheat and Oat-Based Whole Grain Foods on Serum Lipoprotein Size and Distribution in Overweight Middle Aged People: A Randomised Controlled Trial — whole grain foods do not change the risk of cardiovascular disease among old fat fuckers like me (or the way I see myself). Score weak point for the pro-grain folks.
- The Dietary Intake of Wheat and other Cereal Grains and Their Role in Inflammation — of all I’ve listed, this is the most useful study for the layperson. It’s a review of studies looking at a connection between eating whole grains and showing signs of inflammation (which, as we’ve discussed, is considered a marker for cardiovascular and cerebrovascular ill health.) Overall, it seems to show that ingesting whole grains is associated with decreased levels of inflammation. I will point out, though, that the comparison group is typically people who eat non-whole grains. Therefore all we can conclude is that whole grains is better than partial grains. We can say nothing about whether avoiding grains altogether might be beneficial. Still, score a weak point for the pro-grain side.
In the words of the author of the last study, “Until now, human epidemiological and intervention studies investigating the health effects of whole grain intake were confounded by other dietary and lifestyle factors and, therefore, well-designed intervention studies investigating the effects of cereal grains and their individual components on intestinal permeability and inflammation are warranted.”
My conclusions? Based upon the listed studies above:
- A high fat diet is good, especially one that relies upon plant fats
- Whole grains appear to be pretty good, too.
Now go forth and have a sloppy butter sandwich… made from the darkest, heaviest, most fibrous chunk of Ezekiel bread you can find, though.