The registered dietitian and professor in the Human Science Department at Ohio State University, Jeff Volek, Ph.D., has done massive work in the domain of high-fat, low-carbohydrate diets, investigating how it affects human health and athletic performance especially.
Since Mr. Volek started out as a dietician, he was educated that low-fat diets were beneficial and that saturated fats and cholesterol should be shunned. But while working with diabetics, he sensed that something was “off.”
“Why should diabetics eat so many carbs?” he wondered. In essence, it drove him to want to understand metabolism and nutrition at a much deeper level. “I was also into self-experimentation . I was at the time into very low-fat diets, thinking that was how I would optimize my own health. But I decided to experiment with a very low-carb diet,” he says.
Low-carb diets can actually benefit both athletes and non-athletes
Volek has spent the last 15 years conducting research in this area, and the outcomes from most experiments have been very encouraging. He states that, “The science continues to point in the direction that there are a lot of applications for these diets for a large number of people. We’re still sorting out a lot of the details, but clearly we need to change the way we feed Americans and the way we think about nutrition in order to reverse … obesity and diabetes.”
He has also conducted comparative research on low- and non-fiber carb diets and athletic performance, and here too results have proved quite positive despite running upstream everything he was taught about diet and performance in school, and likewise in most of the scientific literature.
Is your diet streaming your metabolic processes in the right direction?
The truth is, most of the nutriment people eat these days drive their metabolism in the wrong direction. The Westernized diet constantly biases you toward using additional no-fiber carbs for fuel. Most Westerners are primarily burning glucose as their primary fuel, which actually inhibits their body’s ability to access and burn body fat.
Healthy fat is in fact superior sort of fuel, as it burns far more efficiently than carbs. As noted by Volek, humans evolved to primarily burn fat as fuel — not carbs — and yet that’s not how we are stuffing our bodies. As a result, we are having a lot of metabolic problems, because we’re constantly inhibiting our body’s ability to burn fuel that we evolved to burn. Without generating ATP you cannot survive at all! The question is how to do that efficiently, without generating harmful reactive oxygen species (ROS), which can destroy your mitochondria and contribute to disease?
Indeed, the key to good health is keeping your mitochondria healthy, which low-carb, high-fat diets tend to do, far more effectively than the opposite high-carb, low-fat diets.
Healthy fat is a ‘cleaner’ burning fuel
Volek’s measurement shows that when people burn fat as their primary fuel, their respiratory quotient can go down as low as 0.7 as opposed to 1, which suggests they’re generating less carbon dioxide. “Regardless of the fuel your body burns, you’re going to generate carbon dioxide and water. But when you burn fat, you generate 30% less carbon dioxide, suggesting it is a lot “cleaner” fuel,” he says.
“To use the term ‘clean,’ that’s kind of a provocative term, but I think it is an appropriate one because … there’s a lot of ‘exhaust’ associated with burning carbs for fuel … free radicals, reactive oxygen species … That contributes to the metabolic problems we’re seeing in this country.”
Also, the most efficient way to train your body to use fat for fuel is to eliminate some of the sugars and starches from your diet. According to Volek, that’s good for everyone, whether you’re an elite athlete or a sedentary diabetic. In essence, the reason why low-carb diets work so well is because it helps you escape this non-fiber, carb-based metabolism that depends on insulin levels to drive blood sugar into cells and use carbs for fuel.
Volek also introduces another expression —carb intolerance — a metabolic impairment that you suffer from if you’re insulin resistant or prediabetic. Volek noted: “It really makes no sense if you’re carb intolerant to be consuming half your energy from nonfiber carbs, and to be trying to force your body to burn more carbs.”
Healthy fat against harmful fats
In Americas people consume damaging fats like refined vegetable oils, which will invariably make your health worse. So when we’re talking about dietary fats, we mean natural, unprocessed fat, found in real foods such as seeds, nuts, butter, olives, avocado and coconut oil. Another good food is raw cacao — it’s an extraordinary well of healthy saturated fats and many beneficial polyphenols.
Fats are critical for a number of reasons: for example, they contribute to the formation of cellular membranes, and it’s really difficult to have good biological function with impaired cell membranes. Dietary fat serves 2 purposes: it serves as fuel, but it’s also a foundational structural component of your biology!
If you’re trying to “shrink yourself” that is shed weight, training your body to access your body fat is the key, or else you cannot shed it. So if you’re overweight, you need to teach your body to burn excess fat. When you’ve reached your maintenance weight, the majority of fat your body will be burning is that from dietary sources.
But how do you make this conversion — to allow your body to become adapted to burn fat as your primary fuel — starting with any excess body fat you already have?
Here’s how to make the conversion from burning sugar to burning fat
The answer is to restrict non-fiber carbohydrates. It’s important to make the distinction about which carbs we’re talking about here, as vegetables are “carbs” too, but fiber carbs will not take your metabolism in the wrong direction — only the non-fiber ones will (think sugars and anything that converts to sugar, such as soda, processed grains, pasta, bread and cookies, for example).
You calculate the dangerous non-fiber carbs by simply subtracting the grams of fiber from the grams of total carbohydrate in the food. Another important point is this:
“Your body can burn both carbs and fat, but your body will burn carbs first. As long as you’re eating carbs, your body will try to burn those first. They’re like the bully cutting in line. You may just think of them as kind of a throw-away nutrient too, because your body cannot store high levels of carb. You have to try to oxidize them and burn them first. But if you’re carb intolerant, which is highly prevalent in this country, you can’t burn carbs, by definition, very well. Your body then only has one alternative, and that’s to convert the carbs you eat into fat. That happens to a greater extent to folks who are insulin resistant or carb intolerant. That really sets the stage for a lot of metabolic problems. Again coming back to how do you train the body to burn more fat; it all starts with removing the availability of carbohydrate because, as long as it’s there, it’s going to take precedence, and will simultaneously inhibit burning of fat.
These are very sensitive and exquisite mechanisms in place for this to work. You eat just a single meal of carbs and your fat-burning shuts down right away. This is why a low- no fiber carb diet works so well to shift fuel use over to fat. You restrict the amount of glucose and starches that you’re consuming, and your body naturally shifts over to preferring fat for fuel. It does take some time to adapt to that. Your cells have to shift over their machinery to handle the increased levels of fat and lipid-based fuels. It takes a matter of weeks to get that adaptation.
But once it’s there, they’re fairly robust adaptations that don’t just go away. This is why there is an adaptation period to a low-carb diet. It can be disrupted though if you reintroduce carbs. But a lot of the adaptations do remain.”
Finding your ideal carb level
Volek i s assertive that a level of non-fiber carbs that allows you to enter into nutritional ketosis (a metabolic state associated with an increased production of ketones in your liver- it’s the biological reflection of being able to burn fat) is on average about 50 grams per day or less of digestible or absorbable carbohydrates. However, we all vary how we respond to the same food, so this is not an exact recommendation.
Some people can be in a full fat-burning state with full ketosis at a level of non-fiber carbs that’s higher than 50 grams. Maybe 70 or 80 grams. Others, especially if you’re insulin resistant or have type 2 diabetes may require less than 40 grams or even 30 grams per day.
Again, it’s worth repeating that when we say carbohydrates, we’re referring to non-fiber carbs only. If you look at the nutrition facts on a processed food package, it will list total carbs, and that’s not what we’re talking about. Don’t get confused about this or you’ll get really nervous. You do need carbs, but you need most of them from plant -based food that is vegetables.
By volume, vegetables are not very calorie-dense. You could have an 85%fat diet, and the volume of the fat would be one-tenth the volume of the vegetables you’re eating. To find your personal carb limit, it’s important to actually measure your ketones, which can be done either through urine, breath, or blood. This will give you an objective measure of whether or not you’re truly in ketosis, rather than just counting the grams of carbohydrates you consume.
“That even varies within a person over time,” Volek says. “You may be able to tolerate more carbs when you’re in your 20s, but suddenly now you’re in middle age and the same level of carbs is resulting in a few extra inches on your waist, your blood sugars are creeping up, you now have prediabetes, or worse. The appropriate level of carb for an individual is bit of a moving target, but it is a very important element to personalizing a diet, which I think is fundamental to this idea of personalized nutrition. It’s finding the appropriate level of carb for you at any given point in your lifespan that allows you to maintain health.”
Research has shown that ketosis is a very safe and a therapeutic metabolic state to be in, specifically if you’re diabetic or suffering from carb intolerance. But there are people who are naturally very insulin sensitive and carb tolerant that don’t need to be in ketosis to thrive. So, there’s room for flexibility, depending on your individual parameters.
Ketogenic diet can solve a number of chronic health problems
Apart from insulin resistance and type 2 diabetes, there are a number of applications for a well-formulated ketogenic diet, including epileptic seizures, especially in kids who are unresponsive to drugs, and neurological disorders such as Alzheimer’s and Parkinson’s. Cancerous growth is another area where ketogenic diets show great promise.
“I think that is the next frontier of ketogenic diets,” Volek says. “There are multiple reasons why many cancers would benefit from a ketogenic diet, not just the decreased glucose availability influx (which many tumors depend on) but also the lower insulin response and less inflammation, as many tumors thrive in a pro-inflammatory environment. There are multiple potential mechanisms by which a ketogenic diet would benefit, including epigenetic effects. We now know that the principal ketone body, beta hydroxybutyrate, is more than a metabolite. It’s more than just an alternative fuel for the brain. It acts like a hormone or a potent signaling molecule that affects gene expression, including upregulating genes that are protective against oxidative stress and enhance the antioxidant status.
Our knowledge and perspective on ketosis is expanding almost daily. It’s all pointing toward positive health effects, which is quite interesting considering that for the last three or four decades, we’ve been demonizing ketones because we only associate it with ketoacidosis.”
Other benefits include the resistance to sugar and other food cravings, as you’re never that hungry once you’ve made the shift. Mental clarity is another great blessing. According to Volek, the U.S. military is showing great interest in ketones for this reason — along with the fact that it boosts physical stamina and endurance.
Being an efficient fat burner may also predispose you to longevity. The single most important variable for controlling the aging process is the ratio of fat versus carbohydrate you burn. The more fat you burn, the slower you’re going to decline. More recent research also supports this notion.
How ketogenic diet may promote long life and increased muscle mass
Recent research has located about a dozen genes associated with longevity. The primary function of one of these genes is to cripple the degradation of branched-chain amino acids, such as leucine, which can be useful for creating muscle mass. Volek mentions that ketones share a close structural similarity to these branched-chain amino acids, and seem to be preferentially metabolized. In other words, ketones spare those branched-chain amino acids, leaving higher levels of them “around”, which promotes longevity and increased muscle mass.
“We learned a lot about ketogenesis from the classic work done by people in the ’60s studying starvation ketosis. One of the reasons why we can survive so long without food is we enter into ketosis, and ketosis spares protein breakdown. One of a more consistent effect we see in people on a ketogenic diet is that leucine levels go up in the blood, because they’re not being oxidized to the same level.Ketones are sparing oxidation and breakdown of important structural proteins, and therefore their levels or concentrations in the blood increase and allow them to do other important signaling-type functions.I do see a very positive interaction here with nutritional ketosis and protein metabolism in general in sparing of the branched-chain amino acids in particular, which are unique in that they are a preferential fuel, unlike other amino acids, which don’t really serve as a fuel substrate,” Volek explicates.
Consuming moderate protein is of great importance
There’s also a “sweet boon” when it comes to protein. You don’t need more protein than your body actually needs. As noted by Volek, this is an important point since there’s a common misconception that low non-fiber carb diets are high-protein diets. In reality, a ketogenic diet must actually be moderate in protein because excessive protein is anti-ketogenic.
On the other hand, you don’t want to consume too little protein, as this may push you into a negative nitrogen balance. As a general rule, you should be eating one-half gram of protein per pound of lean body mass per day, which for most sedentary guys is 40 to 70 grams, but this may be higher for athletes and bulkier individuals. However, the best approach is to measure ketosis to know you are not over-consuming protein.
“It’s also important to maximize the quality of the protein,” Volek says. “I am a general proponent of high-quality protein sources [such as] whey protein. Most animal sources of protein maintain these essential amino acids (discussed above). I do think, with the potentially unique characteristics of leucine and branched-chain amino acids, we may discover that it’s beneficial to include extra leucine even within a context of a ketogenic diet … Especially if you’re an athlete wanting to enhance lean body mass, there could be some benefit to specific use of leucine in particular after exercise or even before exercise.
I generally think including all three [is best]. Leucine is a potent stimulator of mTOR and protein synthesis in skeletal muscles. It’s one thing to turn on the machinery, but you still have to have the building blocks in order to build proteins. I do think it’s important that you have full complement of the essential amino acids to make sure that you have all the material there to take advantage of the signaling effect of leucine,” he states.