Posted March 07, 2014
We were all indoctrinated early. Living anywhere in the civilized world (but especially in the grain-obsessed US) it was ingrained in us: Carbs are a dietary staple. Eat 6-11 servings of carbs per day. etc etc
There's now a lot of evidence showing that this long-running carb-dogma is actually quite misinformed.
Carb-restricted, high-fat diets are growing rapidly in popularity and deliver excellent results for a ton of people. The best high-fat diets of today are a world better informed and more sophisticated than early carb-restricted diets of the mid-to-late 90's (Atkins, etc).
In fact, I believe that a switch to a high-fat diet can potentially be one of the most transformative nutritional practices a person can adopt. Speaking personally, the switch to a dialed high-fat diet has completely revolutionized the performance of my own body and mind.
Here's some things to consider:
1. Evolutionary Evidence
There are a few pretty convincing points that show the majority of our evolutionary history was spent eating a high-fat diet.
- Anthropological Evidence - When anthropologists look at the diets of pre-agricultural societies, the vast majority of them got the bulk of their calories (somewhere around 60%) from fats. As hunter-gatherers, most of these fats were animal fats. This is significant, as animal fat is primarily comprised of short-chain fatty acids that the body uses very efficiently (we'll touch on this later).
- Diets Of Other Mammals - The diets of mammals vary widely, of course, but there are a few patterns to note. Carnivorous animals eat a very high percentage of their calories as fat, sometimes up to 80%.
On the other end of the spectrum are grazing animals (such as cows, horses). While at first glance it seems that they eat almost entirely carbohydrate, there is a critical difference in the way these animals process their food. Bacteria in the digestive system of a grazing animal converts fiber in the food into other types of nutrients, particularly short-chain fats. So although grazers eat primarily carbohydrate, by the time food is digested, it is primarily these short chain fats that are delivered to the brain and body. A cow, for example, eats almost entirely grass but gets close to zero carbohydrates in it's diet (as but bacteria transform the grass into short-chain fats).
Omnivorous mammals (like pre-agricultural humans) tend to eat around 60% of their calories from fat when food scarcity is not a factor and they can make choices based on preference.
So what can we learn here? First - in human history, diets with a large portion of the calories coming from carbohydrates is an entirely post-agricultural-revolution phenomenon. This means less than 10k years ago. Prior to that, diets were almost exclusively low-carbohydrate and high in animal fats.
Hominids first started to appear 22 million years ago and modern homo sapiens around 200k years ago, so that gives you a sense of what a small percentage of our evolutionary history has been spent eating high-carbohydrate diets. The evidence from the diets of other mammals only drives this point home.
While the evolutionary evidence is intriguing, it's admittedly meaningless without some more practical, applied evidence of the benefits of a high-fat diet. Fortunately, there is no shortage of this either...
2. Escape The Blood-Sugar Cycles
To understand why fueling the body with fats is so beneficial, it's useful to first consider what takes place in our bodies when we eat a carbohydrate-heavy meal. After you eat a carb-rich meal, over the next 30 minutes to 3 hours-or-so, your digestive system will break down the carbohydrates in your meal and convert them into simple sugars so they can be absorbed into the bloodstream. (how quickly or slowly this happens depends on the types of carbs and how much fiber, fat and protein were in the meal)
Correspondingly, blood sugar rises and metabolism (and thus, available energy) rises along with it. Insulin is released and tells your cells to start storing all of this carbohydrate (as glycogen or fat).
At some point, blood sugar peaks and then starts to fall. Shortly thereafter your brain notices that it no longer has enough blood sugar to fully function. Your cognitive performance dips, energy levels drop, you get moody and your brain triggers your hunger mechanism.
You eat again and restart the cycle: Eat. Blood sugar up. Blood sugar down. Repeat.
Your body has other potential energy sources it could mobilize - stored glycogen or fat - but it won't because by eating a diet heavy in carbohydrate, you've trained your body to use primarily carbohydrate from the food you consume for energy. Your blood sugar has to drop significantly for an extended period before your body will start to mobilize stored energy sources in adequate levels. In essence, you're trapped. If you don't continue eating carbohydrate regularly throughout your day, you're going to feel like shit.
If all of this blood sugar up, blood sugar down sounds like it would be taxing for the body, you're right - it is. Overall energy levels and cognitive performance end up being lower than if your brain and body had been fueled more stably throughout the day.
This is where a high-fat diet has the potential to be hugely beneficial...
3. Improved Energy Levels
Now that we have a picture of how a carbohydrate-dominanated diet affects the body, let's contrast this with how the body uses fats.
Fats and carbohydrates are both digested in the gut, although fats break down quite a bit slower. After digestion in the gut, most carbohydrates are absorbed directly into the bloodstream (as glucose, a simple sugar). Fats, however, go to the liver for an additional processing step, either for storage or conversion into ketones. It is these ketones that your brain and body are able to use for energy metabolism in place of sugars.
Where carbohydrate digestion is defined by a dramatic rise-fall of available metabolic energy as blood sugar peaks then falls, fats are converted into energy stably and consistently over many hours.
When your body is procuring the majority of its energy from fats, your metabolism is in a state referred to as ketosis. Everyone with a healthy metabolism will switch into ketosis at least once in a 24-hour period (generally during sleep). The fundamental idea behind a high-fat diet is to eat the foods that keep your body in ketosis for the majority of a 24-hour period.
Why? For one, the way you experience your energy levels while in ketosis compared to in carbohydrate-metabolism cycles changes dramatically. Gone are the dramatic swings in energy levels; the late-morning lulls, mid-afternoon drowsiness, etc. Gone too are the swings in mood that often accompany these swings in energy levels. For a lot of people, even their experience of hunger changes and lessens.
When your body is trained to operate efficiently in ketosis (nutritionists refer to this as keto-adapted), you experience energy as stable, consistent and abundant.
4. Better Cognitive Performance
No organ in your body thrives on ketones more than your brain. One of the most common benefits reported by people who switch over to a high-fat diet is improved mental clarity and cognitive performance. There's a few reasons why this is the case...
First, is a simple energy consideration. The brain accounts for around 2% of our body weight, on average, but can use as much as 25% of the body's energy in a given day. Because of this high rate of energy usage, the brain is stressed by cycles of high- and low-blood-sugar more than other tissues in the body.
The second reason the brain prefers ketones as a fuel is more specifically a neurochemical one. Glutamate is an amino acid that functions in the brain as an excitatory neurotransmitter. The brain will also convert glutamate into one of two things, GABA (an inhibitory neurotransmitter) or aspartate (another excitatory neurotransmitter). Maintaining a balance between GABA and these excitatory neurotransmitters is crucial to optimal brain functioning.
For reasons we're not quite sure of, a brain using ketones for energy preferentially converts glutamate into GABA, maintaining a healthy balance. A brain using glucose (carbs) for energy converts glutamate primarily into aspartate, resulting in an excess of excitatory neurotransmitters, a state that is mildly neurotoxic for the brain (or significantly neurotoxic depending on the degree of imbalance).
Finally, the metabolic processes that convert ketones into energy are a bit "cleaner" than those that convert glucose into energy. Glucose metabolism produces slighly more oxidative free-radical byproducts than ketone metabolism. In the rest of your body where toxins are cleared readily, this isn't a big deal. Your brain, however, a highly sensitive organ where energy usage is quite high making this a bigger concern. Higher levels of oxidative byproducts means more damage to sensitive neuronal membranes and negatively affected mental performance.
It's an interesting side note that recent studies have shown coconut oil to be a surprisingly effective treatment for alzheimer's and other neurodegenerative diseases. Coconut oil is a rich source of MCT's, a specific type of fat that converts readily to ketones and promotes ketosis in the body.
5. Improved Body Composition - This is somewhat counterintuitive at first glance - the idea that eating large amounts of fat could actually lower your overall body fat. But, indeed, this tends to be the case more often than not.
This is in part because the metabolic pathways that convert fats from your diet into energy are largely the same pathways that turn stored body fat into energy. When your body becomes keto-adapted, these metabolic pathways become more robust and your body "gets better" at burning its own fat stores.
Implementing A High-Fat Diet: Things To Consider
There's a lot to consider when embarking on a high-fat diet. Really, this deserves a whole article in itself, but for now, here are some pointers.
- Allowing The Body To Adapt - I've used the phrase "keto-adapted" a few times throughout this article, an important idea to consider when starting a high-fat diet. The metabolism of someone who is months or years into a high-fat diet looks quite different than that of someone eating a standard carb-dominated diet. Over the first few weeks of a high-fat diet, your body will up-regulate production of the enzymes involved in the digestion and conversion of fats into ketones.
- The Types Of Fats Matter - Certain types of fats are converted far more readily into ketones by your body. Specifically, short- and medium-chain saturated fats require minimal digestion in the gut before they can be sent to the liver for conversion. Because they are converted into energy so easily, these fats actually encourage your body to move into ketosis quicker and stay there longer.
Good sources of short-chain fats include butter and ghee (although anything not completely grass-fed/pasture raised should be avoided).
Medium-chain fats are found in a number of plant oils, but far and away the cleanest source for these is coconut. Coconut oil is about 65% medium-chain fats by volume. I am a huge fan of Cocotella, an artisan raw coconut butter. It is an excellent source of medium-chain fats plus a good source of soluble fiber to keep the gut flora happy. (Oh, it's completely delicious)
Remember the BPA scare of a few years ago?
Nalgene was pressured into doing a recall of all of their bottles and the rest of the industry was left scrambling to get BPA out of their products. It's likely this sounds familiar to you, but do you actually know what the issue was? BPA was (and realistically, still is) a common additive to plastics to make them more durable. Unfortunately, it was also discovered to be a powerful xenoestrogen, a synthetic chemical that mimics the natural estrogen in our bodies.
With the BPA scare of a few years ago, it was a connection to disrupted fetal development that made all of the headlines. But in reality, this is only one of many (creepy) ways these synthetic estrogens negatively impact our bodies.
While BPA use has decreased significantly in the past few years, it has not been eliminated by any means. Even more troubling, BPA is only one of perhaps hundreds of chemicals we come into contact with on a daily basis that can act as xenoestrogens.
What Are Xenoestrogens?
The prefix "xeno-", of course, means foreign. Xenoestrogens are chemicals in our foods and environment that, when ingested, interact with our body's estrogen systems. The birth control pill, for example, is a prescription synthetic xenoestrogen.
Xenoestrogens are particularly a concern because they often trigger our body's estrogen systems far more powerfully than our own naturally-produced (endogenous) estrogen does.
Why is this a problem? Estrogen is a common hormone in the body, a natural chemical released by the glands of our endocrine system used to send messages to other tissues in the body. Although it is typically thought of as a female hormone, it is also present (and quite important) in men's bodies as well. Essentially every organ and tissue in the body has estrogen receptors. When estrogen circulates in the body it binds to estrogen receptors and triggers certain effects in that organ or tissue (the effect dependent on at what levels and how often it circulates).
Estrogen has well-established roles in fetal, childhood and adolescent development. It also plays a central role in weight gain, sex-organ health, fertility, immunity and mental health.
Clearly, this is not a system you want to screw with.
What Are The Negative Effects Of Xenoestrogens?
Here is a list of the impacts research has shown xenoestrogens to have in the body:
- Impair development of reproductive organs in eutero.
- Decreases sperm concentration and semen quality in adult male rats.
- Correlated with infertility and decreased semen quality in human adult males.
- Promotes early puberty onset in boys and girls.
- Promotes weight gain in women and men.
- Accelerates hair loss in women and men.
- Glandular (hormonal) dysfunction.
Only The Tip Of The Iceberg
The list above represents what has been studied thus far by endocrinologists and biochemists. The reality is though, this is a partial list at best. Xenoestrogens are a relatively new concept in endocrinology and are severely under-studied. The research that has been done thus far is on only those effects that are the most easily observed and measured (such as disrupted fetal development).
Estrogen and estrogen receptors are so widely distributed in the body, screwing with this system in any way is going to have significant effects on essentially every tissue in the body. As much as is possible, we want to let our bodies regulate estrogen naturally, on their own.
Plastics - The #1 Source Of Xenoestrogen Exposure
For most people, still far and away the biggest source for xenoestrogen exposure is plastics, particularly soft plastics, that come into contact with foods and beverages we eat. Even after the recalls of a few years ago, BPA is still used in many plastic products. But BPA is not the only chemical commonly used in plastic production that has been shown to act as a xenoestrogen in the body. Phthalates are widely used in softer plastics and have been shown to disrupt endocrine function.
When plastics are exposed to heat or sunlight, or even just sit for a sufficiently long time, they start to break down and these chemicals will leech into your foods and beverages.
Water bottled in plastic is essentially guaranteed to be contaminated. The soft plastics used for these cheap bottles are certain to be made using BPA and/or phthalates. These bottles are manufactured at high temperatures and are actively off-gassing when they are filled with water. The bottles are then capped and sit for months (sometimes years) in storage and transit. The result is water significantly contaminated with xenoestrogens, solvents and other toxic chemicals.
Another thing that deserves special attention here is your dishwasher. Putting plastics in the dishwasher exposes them to high temperatures and water simultaneously, pretty much perfect conditions for leeching of chemicals. DO NOT ever put plastics in the dishwasher. Not only will that plastic be guaranteed to contaminate the next food it comes into contact with, but the rest of your dishes will be coated in a fine film of xenoestrogens and other chemicals as well.
The bottom line is keep your foods and beverages away from plastics whenever possible. Stop buying foods and beverages packaged in plastic and start replacing your plastic dishes and tupperware with glass and ceramic.
Other Sources Of Xenoestrogen Exposure?
- Pesticides + Herbicides - This is the REAL reason to buy organic produce as far as I'm concerned. I've seen studies recently highlighting that there are no significant differences in nutritional quality between organic and non-organic produce. This is a red herring of sorts and as far as I'm concerned, nutritional content is not really the point.
The real reason to buy organic is to avoid the pesticides and herbicides that conventional produce is so commonly contaminated with - many of which are known xenoestrogens and endocrine disruptors. Atrazine (a common herbicide), Endosulfan and Glyphosate (common pesticides) are all known hormone disruptors.
- Processed Foods - Processed foods can contain a shockingly large number or chemicals unregulated by the FDA known to be xenoestrogens. These include preservatives (BHA, propyl gallate) and colorings (Red no. 3).
- Skin Care Products - Lotions, soaps, shampoos and makeups often contain known xenoestrogens (4-MBC, parabens, phthalates, etc). Buying the "natural" or "organic" brands unfortunately doesn't always eliminate your risk for exposure, but it does reduce it significantly. Of course, there's only one thing you should be putting on your skin anyways.
- Teflon Cookware - If over-heated, teflon will leech a powerful endocrine-disrupting chemical. It's a good idea to switch over to ceramic coated pots and pans or cast iron. I use pans similar to this one.
- Conventional Meat and Dairy - Livestock are often given synthetic hormones to force them to gain weight. These synthetic hormones remain in the fat and milk of the animal.
Be Proactive, Supplement + Protect Yourself
Following the guidelines above, you will significantly reduce your exposure to xenoestrogens. Unfortunately though, no matter how diligent you are, some level of exposure is inevitable. If you want to be proactive, there are supplements you can take to help your body breakdown and remove these foreign estrogens from your body. Here are the two I take on a daily basis:
- Calcium-D-Glucarate - Effectively a source of D-Glucaric Acid, a criticial component of your body's natural system for removing xenoestrogens from the body. Our body packages certain toxins, including xenoestrogens, in little units called glucuronides such that they can be removed safely from the body. D-Glucaric Acid assists in this process by preventing glucuronides from being broken down once they "capture" a toxin, as sometimes happens otherwise. I take 400mg daily of Calcium-D-Glucarate from Life Extension Products.
- Diindolmethane (DIM) - DIM is a natural compound found in kale and other cruciferous vegetables. It aids your body in breaking down harmful estrogens including xenoestrogens. I take 100mg daily of DIM from Source Naturals.
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