Low-carb diets frighten some doctors, dietitians, and trainers. Many health experts dont believe a person can be healthy on a low-carb diet long term and dont really understand how it affects the bodys metabolism.
After visiting and interviewing Jeff Volek, PhD, RD, one of the nations leading low-carb diet and research experts, it became clear to me that an inevitable change in understanding the impact of diet on human health is coming and its backed by profound scientific study.
Before I get into the interview with Dr. Volek, I would like to say that to summarize the interview may not give it the full credit it deserves. So, while Ill highlite a few points here, Ive included virtually the entire 90 minute interview in this article.
1. The bodys metabolism can healthfully and safely adapt to a low-carbohydrate diet long term.
2. Carbohydrate restriction not only helps people manage type-2 diabetes and other insulin resistance issues, it can reverse many existing cases of type-2 diabetes and put a high proportion of cases with metabolic syndrome into complete and sustained remission.
3. Most people misunderstand the metabolic effect of ketones, which are byproducts of fat breakdown, and how these ketones can healthfully affect the body long term for weight management and for managing Type-2 diabetes.
3. Dietary saturated fat is not bad when you are low carb adapted.
4. Dietary sugars and refined starches are not needed to feed your brain or fuel exercise.
5. Theres a revolutionary new sports drink that is not sugar based that helps athletes maintain energy over longer periods of time than traditional sports drinks.
6. Mineral and electrolyte management is the key to avoiding side effects typically associated with low carb dieting.
7. Some dietary supplements may be relevant for certain individuals.
8. Dr. Volek has virtually been following a low carb diet for over 20 years and currently has a daily dietary intake of over 70% fat, about 5-10% carbohydrate, and 15-20% protein, yet maintains a healthy body weight, healthy lipid profile, has an amazing level of focus and energy. He has produced over 250 scientific studies at the nations top kinesiology program (UConn) and contributed to several books including,The Art and Science of Low Carbohydrate Performance, The Art and Science of Low Carbohydrate Living, and the New York Times best seller, The New Atkins for a New You.
Dave: Thank you Dr. Volek for taking the time for this interview. I admire your work because it not only offers much to help others looking to address health concerns, but it offers something that many people do not truly understand low carbohydrate diets.
Some people believe if they go on a low carb diet, it will be bad for their health. They think that on a low carb diet, they have to eat too much fat and that if they do, it will clog their arteries or without enough carbs, they might get keto-acidosis, a dangerous threat to their health. But, I learned from your books that there is a big difference between nutritional ketosis that comes from following a low carb diet, and keto-acidosis, commonly seen in diabetics. Can you explain?
Jeff Volek, PhD, RD
Dr. Volek: This is a highly misunderstood aspect of metabolism. The first and probably most important point regarding the difference between nutritional ketosis and keto-acidosis is one of magnitude. The levels of ketones (byproducts of fat metabolism) in keto-acidosis, which is primarily seen in a person with Type 1 diabetes where you have insulin insufficiency, often exceed 10-20 millimolar (level of blood ketones), which is a serious life-threatening condition.
When compared with an individual on a low carb diet, which elicits nutritional ketosis, however, we are generally looking a blood ketone levels (levels of ketone circulating in the blood) of 0.5 to 3.0 millimolar. So the difference in concentration between keto-acidosis and ketosis is significant. In nutritional ketosis, you dont have a change in acid-base status of the blood,.
Its no different than having a normal level of glucose versus a hyperglycemic state (high blood sugar), which is not good, or a hypoglycemic (low blood sugar). So theres an optimal or desirable range for ketones in the bloodstream where youll see many metabolic benefits, and a healthy person will not achieve diabetic keto-acidosis, which is due to a fundamental deficiency in insulin.
Dave: Many people lose weight very quickly on a low carb diet, but get concerned about doing it long term. Is it safe to live long-term on a low carb diet?Dr.Volek: Yes, probably the strongest evidence for that comes from the fact that as humans we evolved probably over 95% of human history on a diet that had relatively low access to carbohydrate dense foods or at least they were consumed intermittently. So the majority of time, human beings evolved in a state of nutritional ketosis. In many ways, you can say were hardwired to respond well to restricting carbs, but we have had limited time to adapt to high amounts of sugars and starches. Even a type 2 diabetic who has a lot of metabolic impairments, adapts fully to a low carbohydrate diet.
Dave: If someone wanted to go on a low carb diet, say 50 or less grams of carbs per day, how would they know if they are in nutritional ketosis or not?
Dr. Volek: Ketones can be measured in the urine as the easiest and cheapest test. But, because nutritional ketosis elicits adaptations over time in the way kidneys filter blood and thus excrete ketones, this methods results should be viewed with a considerable degree of caution.
Ketones can also be accurately self-assessed using handheld devices that measure ketones from a finger stick of blood.
Dave Barnas, MS, CES, NASM-CPT
Dave: As alarming as it is to most people, you wrote and provided the references that current evidence shows no association between dietary saturated fat and cardiovascular disease, but there is an association of increased risk for cardiovascular disease and diabetes with increased amounts of saturates circulating in the blood. What then, from a diet perspective, is associated with an increased amount of circulating saturates in the blood?
Dr. Volek: Carbs control insulin and insulin controls lipid (fat) burning for fuel. So, in our work, what weve shown, is that even though youre eating more saturated fat on a low carb diet, perhaps 2-3 times the amount, the amount of saturates in your blood goes down because youre body prefers to burn saturated fat as fuel.
Many people like to embrace the common aphorism, You are what you eat, but this is clearly not true, instead, You are what you save from what you eat. And when youre on a low carb diet, your body is preferentially oxidizing fat for fuel, so youre not storing it or accumulating it in cells, arteries, or fat stores. So if anything, dietary carbs are more related to increasing membrane levels of saturated fat. Dietary saturated fat has little correlation with the level of saturated fat in the body.
Dave: Thats a huge shift in paradigm because a lot of people dont realize this and believe saturated fat causes heart disease.
Dr. Volek: Not just a lot of people, about 90% of medical professionals and even lipid researchers find this mind boggling.
Dave: To me, it makes total sense. If youre insulin is up from too many carbs, then your body will respond with elevated saturates in the blood. So it makes sense.
Dr. Volek: It really threatens about 40 years of dietary policy that has been obsessed with the idea dietary fat increases your risk for heart disease. Rather than get stronger over time, if anything, the evidence has gotten weaker and weaker for this outdated hypothesis.
Dave: Do you recommend a low carb diet to everyone?
Dr. Volek presenting.
Dr. Volek: I dont push low carb on people, but Im a strong believer that we should make it available for people and if theyre willing to listen, then Im more than happy to talk to them about it. Its not right for everybody. The truth is there is no one perfect diet or cookie cutter approaches. This is why I think personalized nutrition is where we need to go. Low carb is just one part of personalized nutrition, especially because many people are struggling with over consuming carbs relevant to their tolerance.
Dave: In your book, you recommend bacon, sausage, and salami. But, some studies link the consumption of these processed meats with cancer. Whats your take on that?
Dr. Volek: Most of that is epidemiological evidence and thats one of the weaker forms of evidence when trying to make direct cause and effect connections between a nutrient and a disease process. One of the real limitations of epidemiological research is that its impossible to account or adjust for all the confounders in an experiment.
For example, for people that eat a lot of processed meats they are probably eating a lot of processed breads with it or have other lifestyle factors that are very hard to control for in these types of experiments either because you dont have the information or it becomes statistically problematic controlling for all these. So, I am not aware of intervention studies where people who are given these foods that show a negative effect, especially in the context of low carb when we know that following low carb for a while changes the bodys metabolism profoundly. Its like the saturated fat story, which could be harmful if youre also eating a lot of carbs because your body is then storing it, but that same dietary saturated fat is having a completely different effect in the context of a low carb diet where it is serving as a fuel and contributes to satiety feeling a fullness. So the evidence is far from convincing on processed meats. They could have a very different effect on the body when following a low carb diet high carb diet because the body is in a different metabolic state.
Dave: So if epidemiological studies are somewhat weaker with regard to correlating diet with health effects, could you share what types of studies that may be stronger?
Dr. Volek: If you look historically at epidemiology, there are many examples where they clearly got the wrong answer based on subsequent follow up research. It was this approach that led us down the flawed path of prescribing hormone replacement therapy (HRT) to prevent heart disease back in the 1990s. Only after the prospective, randomized Womens Health Initiative data were analyzed was it discovered that HRT actually causes heart attacks (and some forms of cancer) rather than prevents them. At the same time, epidemiological studies have a place in that they can give you a starting point for a hypothesis. Then, youd test that hypothesis with a more rigorous experiment such as a longitudinal intervention study in a cohort where you manipulate that particular nutrient over time within a person to see how it changes. Even in those types of studies there is wide variability in the level of control and compliance to dietary protocols so the results have to be interpreted with caution.
A lot of the low carb studies are not well controlled, especially the long term ones. Even those are very limited in what theyre telling us and a lot of people use those year-long low carb studies to say theyre no better than low fat for weight loss. They are so poorly implemented and have very low compliance and adherence that you dont know what the heck people are eating when youre out past six months and in some cases the researchers dont even bother to collect information on dietary intake.
These studies are quite challenging to have participants maintain a specific diet when theyre living in a free living environment that have all the stresses of daily life. It requires a lot of effort, and you know as a trainer, to get people to make lifestyle changes requires a lot of effort, specifically it takes person power to spend time with them, develop a relationship and build rapport with them, provide them the information and education, and counseling they need to successfully follow the diet.
Weve done a lot of free living studies pretty well. Weve also done a lot of feeding studies, which is another level of control where you prepare the food for people. Those are even more work and get very expensive, which is why you dont see many long term feeding studies. Theres always a compromise of a studys level of dietary control versus (n size) the number of people participating in the study. Its hard to study 100s of people where youre feeding them over time.
The results of well-controlled low carb studies are nothing short of amazing in terms of traditional and emerging biomarkers (distinct biochemical, genetic, or molecular characteristic or substance that is an indicator of a particular biological condition or process; eg. a blood test to measure protein biomarkers for cancer). Even in some of the low carb studies that are somewhat sloppy or poorly conducted, you still see low-carb winning, which shows you how powerful it is because even when its administered in a sloppy way, it still tends to work better.
Dave: OK, Id like to shift gears for a minute. Studies with athletes. What studies have shown that the same athlete can perform better on a low carb diet than if s/he followed a balanced or high carb diet?
Dr. Volek: Well, it depends how you define low carb first. Theres been a number of studies that have compared high fat to high carb with athletes. And with the high fat diet, its usually 20% carb, but its not low enough in carb where youre inducing nutritional ketosis. So you dont have keto-adaptation. But, a lot of those studies are showing that when you give adequate time, there are consistent metabolic adaptations leaning toward burning more fat relative to carbs. How that translates into performance is a bit mixed.
Most of those studies usually show no difference in performance between high carb diets and high fat diets. Theres a couple of studies that show improved performance on high fat and you might find one with a decrement in performance, but its usually no difference or better performance.
But, very few published studies have examined keto-adapted athletes, which is when you take the carbs down further (about 50 grams or less per day).
Dave: The only study I saw with athletes was the one by Dr. Stephen D. Phinney with cyclists discussed in your book.
Dr. Volek: Yeah, theres really Steve Phinneys and there was Paolis study from Italy that was just published.
Dave: What was Paoli assessing strength or endurance?
Patrick (post doc also attending the interview): They looked at a variety of measures with gymnasts including push-ups, vertical jump, and VO2 max VO2 max, or maximal oxygen uptake, is one factor that can determine an athletes capacity to perform sustained exercise and is linked to aerobic endurance. The study was very regimented, had good compliance and the athletes consumed roughly 20 grams of carbs a day.
These gymnasts adapted well vertical jump and power didnt change. Their ability to do push-ups, pull-ups, and aerobic capacity did not change after five months of eating virtually no carbs.
Dr. Volek: My research group also performed a low carbohydrate diet and resistance training study. We focused on body composition and metabolic responses. We didnt show a decrement in performance; in fact the participants got stronger, as youd expect with training for both the high carb and low carb groups. But, there were differences in body composition that were favorable toward the low carb.
Dave: I saw pictures from one of your presentations on YouTube featuring some athletes who may have tried low carb dieting including Olympic skier Lindsey Vonn and US professional tennis player Marty Fish. Have you researched with them?
Dr. Volek: Weve been studying more the ultra-endurance athletes.
Dr. Volek: Mainly runners, actually. My research team studied runners at the Western States 100 last year. The Western States 100-Mile Endurance Run is the worlds oldest and most prestigious 100-mile trail race. Starting in Squaw Valley California near the site of the 1960 Winter Olympics and ending 100.2 miles later in Auburn, California, Western States. There were several athletes restricting carbohydrates to some extent. In fact, the guy who won the race, (Timothy Olson), was a self-proclaimed low-carb athlete. He not only won, but he set the course record.
Dave: Was he keto-adapted? ( keto-adaptation concept that the human body requires a few weeks to adapt to eating a low carbohydrate diet, roughly 50 or less grams of carbs per day.)
Dr. Volek: Its tough to say. We did not have blood (for research purposes) on the guy who won, but we had blood on a couple of other guys that were in nutritional ketosis. Most of the low carb athletes are eating some carbs during the race, but the amount of carbs they are eating is such a low amount of calories relative to the energy expenditure. So we dont really know, but theres a good chance that these guys are keto-adapted even when theyre eating small amounts of carbs during exercise. However, this is something we have not studied in detail and requires further experiments.
Dave: So are you looking forward to studying that?
Dr. Volek: Were trying to, yeah. It was a great experience to establish some relationships with the event staff and several athletes that are training using a low carbohydrate diet. So, wed like go back. But the hardest part of doing research is finding adequate funding. Its hard enough to get funding to study a mainstream area of science, let alone a controversial topic such as low carb. Also research funding is targeted more at clinical work that human athletic performance so its especially hard to fund this type of work.
Dave: That reminds me of a sports drink product (Generation UCAN powered by SuperStarch, a healthy, natural, gluten-free innovation in carbohydrate nutrition. SuperStarch is a complex carbohydrate (derived from non-GMO corn) that uniquely stabilizes blood sugar and causes virtually no reaction from the fat-storage hormone insulin) you mentioned in your book by Generation UCan.
Its a revolutionary sports drink?
Dr. Volek: Yeah, thats another fascinating discovery.
Dave: Based on the positive reports Ive read about it, it seems as though it would be more mainstream eventually.
Dr. Volek: Yeah, its getting there. UCan is a relatively small start-up company that launched about five years ago. They are a slow but continuously growing Connecticut based company.
Dave: Have there been studies with it? I saw the difference in how the drink affects insulin in a much slower, more subtle and longer lasting way than traditional sports drinks with sugar (glucose, sucrose, maltodextrin).
Dr. Volek: The product was developed initially to help manage kids with glycogen (stored carbohydrate) storage disease in which they lack the enzyme glucose-6-phosphatase in the liver so they struggling maintaining blood sugar levels. Its a rare, devastating disease for the kids and their families. These kids need to be fed every couple of hours because the risk going hypoglycemic (low blood sugar). This is day and night, everyday of a kids life and you can imagine what stress this causes to families to get up in the middle of the night to feed their kid. A lot of them have feeding tubes.
There was a researcher in Scotland who was interested in this disease and he was screening a large number of carbohydrate sources with various processing techniques to find one that would provide a sustained maintenance of blood sugar. He discovered superstarch and has the patent on technology. So that is how it was discovered. Its a waxy maize, high amylopectin (a soluble polysaccharide and highly branched polymer of glucose found in plants) corn starch. But thats not whats unique about it.
It goes through this meticulous 24-28 hour heat-moisture application that changes somehow, and we dont know exactly how), the way its exposed to enzymes in the GI tract so that it gets slowly absorbed. Its not a resistant starch, which would get stuck in the GI tract and not get absorbed. Instead, it is fully absorbed so it has 4 kcals/gram, but the absorption is slowed down considerably. Theres been two published studies in the glycogen storage disease literature showing the starch extends maintenance of blood sugar. This is validated by real-World clinical results that allow kids to now go 8-10 hours now in between meals.
And theres one clinical study with Type-1 diabetics who often have problems with nocturnal hypoglycemia (when they go hypoglycemic at night). The results showed that superstarch before bed resulted in less hypoglycemia.
And then theres one study in athletes that the company funded a couple of years ago at the University of Oklahoma, which is probably the one you may have heard about.
Dave: When I first learned about this product, I was surprised more athletes werent using it.
Dr. Volek: Well theres no doubt this starch gets absorbed very slowly and because of that it has distinct metabolic and hormonal effects.
Dave: So could you see it becoming more popular long term?
Dr. Volek: Its clearly a better choice than sugar, which is pretty much 99% of the other sports drinks out there. Whether its glucose, fructose, sucrose, maltodextrin, its all fast-acting carbs. I dont see a lot of benefit to spiking glucose and insulin levels, even if youre an athlete who can tolerate it to some extent compared to a person who has insulin resistance.
The sugar-based supplements are problematic in many of the ultra endurance runners who have to consume a lot of gels and drinks to complete their training and events. We are beginning to learn that over-emphasis on sugary fuels and carbohydrate oxidation can lead to GI complications, inflammation, oxidative stress (aconditionofincreasedoxidantproductionincells characterized by the release of free radicals andresultingincellular damage) and cell membrane damage. Its well known in that community (ultraendurance athletes) that a lot of them are known as vomiters because they just cant tolerate the carbs. They know they need the energy and theres no other alternative so they keep chucking it in, but then a lot of them just vomit multiple times during these races.
Anecdotally, when athletes switch to superstarch, they dont have that problem. Partly because I think superstarch is such a huge molecule it has an extremely low osmolality (concentration of a solution) and that is one of the big factors in palatability. The higher the osmolality, the longer it will sit in your stomach and potentially cause gastric problems. So the superstarch is extremely hypotonic and gentle on the stomach.
There are also a lot of the athletes restricting carbs that may not be using Ucans product. They also experience benefit from not taking all these gels in terms of GI symptoms and faster recovery. I did not appreciate that because Ive only been recently exposed to this elite group of endurance athletes. My background as an athlete and as a researcher has been in the strength and resistance training world.
(To learn more about SuperStarch bars, click here).
SuperStarch Snack Bars
Dave: Yeah, its interesting to see and learn how various athletes adapt to different types of extreme training and competition. So now some questions about supplements. I saw you produced over 200 something research papers and I did not research a lot of your work on supplements I saw creatine I think.
Dr. Volek (lightheartedly): You didnt want to read 200 papers (chuckle)?
Dave: (lightheartedly):I couldnt find them. (chuckle)
Dr. Volek: (lightheartedly): Im just kidding. (chuckle)
Dave: I know. (chuckle)
Dr. Volek: (lightheartedly): I cant even read a paper all the way through anyways.
Dave: (smile). OK so heres what Id like to do for the readers of our newsletter. Clearly you know a lot about supplements way more than the average person is going to know. And if you were to say, based on scientific research, what dietary supplement would you recommend to the public? Would there be one?
Dr. Volek: Theres a couple that I think have a place. I did a lot of work with creatine when it first became popular in the mid 90s. And theres a substantial amount of research showing creatine improves high intensity exercise performance and augments adaptations in strength and lean body mass when consumed as part of a resistance training program. And its perfectly safe.
Its an incredibly benign substance so I have no qualms about recommending creatine for strength and power athletes. And in fact, if I was training or training competitive athletes, I would say it would be pretty much mandatory that theyd be on it because it works and its legal and its safe.
Dave: OK, but just the general public, not the guy whos going to the gym. Maybe for somebody who is around 55 years old. I get a lot of questions about omega-3s, general multivitamins, coenzyme Q-10 (I worked for a cardiologist who wrote books about it).
Dr. Volek: Well, I think its prudent to get a good source of omega-3s. So if youre not eating fish once or twice a week, its probably prudent to take a supplement with omega-3s. You really want to try to aim for a better balance of omega-3 to omega-6 s as most people are completely out of proportion with regard to omega-6 to omega-3 intake because of the ubiquitous amount of soybean and corn oil in the food supply. (side note not from Dr. Volek: This dietary imbalance of omega-3 to omega-6 may explain the rise of such diseases as asthma, coronary heart disease, many forms of cancer, autoimmunity and neurodegenerative diseases, all of which are believed to stem from inflammation in the body. The imbalance between omega-3 and omega-6 fatty acids may also contribute to obesity, depression, dyslexia, hyperactivity and even a tendency toward violence.)
Dave: So youd recommend anomega-3 supplement then?
Dr. Volek: Yeah.
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