We recently sat down with Jeff Volek, Phd to discuss the ins and outs of low carbohydrate diets. Dr. Volek is an expert on low carbohydrate diets having conducted several research projects and co-authored several books on the subject too. His accomplishments are praised by low carbohydrate dieting experts too. Dr. Michael Eades, author of ‘Protein Power’ says that Dr. Volek’s book (co-authored with Dr. Stephen Phinney) ‘The Art And Science Of Low Carbohydrate Living’ is “the best low carb book in print.”
Whether you have been eating low carb for a long time or are just getting started with the diet you’ll learn something in this interview to make it more effective for improving your health, losing weight, and building muscle.
Stayfitcentral: How did you become interested in low carbohydrate diets?
Dr. Volek: For me it started in about 1991. I had just graduated with a degree in dietetics and thus was indoctrinated with the low fat dogma. However, after reading Dr. Atkins book I decided to try the diet even though I was not overweight. I experienced nothing short of an epiphany characterized by marked improvements in energy, well being and body composition. This information went against everything I learned in dietetics. After spending thousands of hours in the Penn State Library I came to the conclusion that most of the dietetic curriculum that resulted in my bachelor’s of science (B.S.) was in fact B.S. In grad school, I began conducting experiments on low carbohydrate diets publishing my first paper on the topic in 2001. I have been busy ever since working hard to understand low carbohydrate diets. In the process I have learned a lot and been fortunate to interact with some great minds on the topic like Dr. Stephen Phinney.
Stayfitcentral: Just how many grams of carbohydrates can you eat daily for your diet to be considered low carb?
Dr. Volek: There are many ways to lower carbohydrates. To get the full benefit in terms of maximizing fat oxidation requires people keto-adapt. Keto-adaptation is a term coined by Steve Phinney in 1980 to describe the process in which human metabolism switches over to using fat almost exclusively for fuel (i.e., a combination of fat burned directly and as ketones derived from fat). Inducing a state of nutritional ketosis and maintaining it long enough to complete keto-adaptation requires a conscientious effort to restrict carbohydrates for two or more weeks. The level of carbohydrate restriction required to optimize fat burning and fat loss varies from person to person, but the most consistent effects will be achieved at levels of carbohydrate below 50 grams per day. However some people may be able to consume 75 grams or even 100 and still remain keto-adapted whereas others may need to go as low as 30 grams per day.
Stayfitcentral: Can you eat too much protein on a low carbohydrate diet?
Dr. Volek: In addition to reducing dietary carbs, an important factor for getting into a state of nutritional ketosis is avoiding over-consumption of protein. For normal weight athletes, this translates into a significant increase in the right types of fat. Protein is necessary on a low carbohydrate diet but it should be consumed in moderation. Too little or too much protein can be problematic. A common mistake many people make when they restrict carbohydrates is they also restrict fat resulting in over-consumption of protein. Some of the amino acids in protein can be converted to glucose, and some increase insulin. The net effect is that too much protein is anti-ketogenic and can impair optimized fat burning. Thus rather than consume large portions of lean meats or other protein rich foods, we encourage athletes to focus on small to moderate protein portions and combine them with generous portions of good sources of fat (e.g., sauces, butter, olive oil).
Stayfitcentral: Do calories matter when you’re eating low carb?
Dr. Volek: Absolutely. But that doesn’t mean you have to be meticulous with counting calories. Most people find that switching over to burning predominately fat for fuel is satisfying and satiating. This prevents the fuel crisis which is common when you eat fast-absorbing carbohydrates that lock you into a dependence on them for fuel. Once keto-adapted, most people report that hunger and cravings are reduced. Thus, it’s much easier to regulate calories and the diet is more forgiving when you miss meals or go long periods without ingestion calories because it can easily tap into fat stores to cover fuel needs.
Stayfitcentral: What adjustments do athletes or fitness enthusiasts need to be make when following a low carb diet?
Dr. Volek: Compared to a person with significant weight to lose, a normal weight physically active athlete requires more calories to maintain weight and provide the additional fuel for exercise. Consumption of carbohydrates and protein remain fairly stable despite changes in goals and activity levels, whereas the amount of fat you consume will be dictated by your energy demands, body weight and composition goals, and satiety.
If you want to lose weight, the total amount of fat consumed will be reduced. If weight loss is not a goal, dietary fat needs to be maintained at a level that matches energy expenditure, thus holding body weight stable. This may sound like getting the right amount of fat could be complicated, but interestingly it’s usually not necessary to count fat calories.
If you want to reduce your percent body fat, the increased satiety gives you the freedom to cut back a bit on how much fat you consume. If you are happy with where you are, just track your body weight or composition and use that information as well as satiety as a guide.
Stayfitcentral: What about pre and post-workout nutrition when eating low carb? Should people eat or drink carbohydrates at these times? If so, what types are best?
Dr. Volek: After a hard workout or competition, it is commonly believed that consumption of quickly absorbed, insulin-stimulating carbohydrates are needed to promote glycogen synthesis. The argument that you need a high carbohydrate intake and high insulin levels to replete glycogen reserves is a moot point if you are keto-adapted, since your use of glycogen during exercise will be dramatically reduced. This would be like worrying about putting regular gasoline in your tank when your vehicle has a diesel engine. Furthermore, we are beginning to learn that there are other more subtle downsides associated with consuming insulin-stimulating carbohydrates after exercise. Consuming even small amounts of carbohydrate after exercise rapidly decreases the release of fatty acids from fat stores and oxidation of fat in the muscle, thereby interfering with keto-adaption, plus also diminishing the beneficial effects of exercise on insulin sensitivity and other cardio-metabolic risk markers. For some athletes, a carbohydrate-induced insulin surge results in a rebound low blood sugar and subsequent stress response characterized by increased counter-regulatory hormones (e.g., epinephrine and cortisol increase) that can manifest as carbohydrate cravings, lethargy, poor physical/mental performance and suboptimal recovery. Over-stimulation of insulin by fast-acting carbohydrates also can have a more insidious effect – diverting glucose into fat storage. This in turn is obviously not conducive to promoting favorable changes in body composition and metabolic health.
This is not to say that all carbohydrates should be avoided by all athletes, and that all athletes will experience these effects. Many athletes may do fine incorporating carbohydrates before during, and after their workout. What athletes need to realize is that consumption of carbohydrates after a workout has the potential to jeopardize some of the adaptations they have made in respect to optimizing fat burning. If athletes want to experiment with introducing carbohydrates strategically around workouts, I recommend they use slow absorbing ones that do not spike insulin. In this regard I recommend looking into SuperStarch by Generation UCAN. SuperStarch is a truly unique and revolutionary carbohydrate source with a low osmotic pressure in the gut, and slow absorption characteristics that significantly blunt spikes in blood sugar and insulin.
Stayfitcentral: Which do you feel is better for athletic performance and building muscle, eating low carb all of the time or occasionally going off to ‘carb up’ (i.e. weekends or every 4-5 days)?
Dr. Volek: There is not a lot of specific research on this topic, so most of what we know is generalized from other research, personal experience, and observation. Incorporating carb-up days intermittently into a low carbohydrate diet can work for some young healthy athletes who show no signs of insulin resistance or other metabolic problems. Some people have difficulty switching back and forth between carbohydrate metabolism and fat metabolism. If you have this sort of metabolically inflexible, and most people do to some extent, I’d encourage people to opt for a sustained low carb approach. As I’m middle-aged now I find I feel and function much better in an uninterrupted state of nutritional ketosis. I’m leaner and mentally sharper when running on ketones, and I prefer not to deviate from that state. If athletes do experiment with strategic use of carbs, again I think selecting those carb sources that do not spike insulin is warranted.
Stayfitcentral: What supplements help athletes on a low carbohydrate diet?
Dr. Volek: A well formulated low carbohydrate diet has adequate levels of all the essential nutrients. However, there may be instances where athletes could benefit from taking additional magnesium for muscle cramps and perhaps long chain omega 3 fatty acids from fish oil to help maintain healthy membranes. Use of creatine monohydrate to enhance anaerobic metabolism and power output during short burst activity is safe and effective (and legal) regardless of dietary carbohydrate level. It’s not really a supplement, but I’ll take this opportunity to mention that additional (supplemental) salt is critically important when consuming a very low carbohydrate diet. This is because the kidneys switch from retaining sodium to excreting a lot of sodium when carbs are reduced. If this extra salt loss is not replaced, plasma volume is contracted which can lead to fatigue and other unpleasant adverse effects.
Stayfitcentral: Should people worry about saturated fats when on a low carbohydrate diet?
Dr. Volek: Recent research results mandate a careful re-evaluation of the widespread belief that dietary saturated fat is harmful. Specifically, multiple recent reports find no association between dietary saturated fat intakes and cardiovascular disease (CVD). There is, however, a consistent pattern of increased risk for both CVD and type-2 diabetes associated with increased levels of saturated fatty acids (SFA) in circulating lipids. This raises the important question as to what contributes to increased levels of saturated fat in the blood. Whereas dietary intake of saturated fats and serum levels of SFA show virtually no correlation, an increased intake of carbohydrate is associated with higher levels of circulating SFA. This leads to the paradoxical conclusion that dietary saturated fat is not the problem; rather it’s the over-consumption of carbohydrate relative to the individual’s ability to metabolize glucose without resorting to de novo lipogenesis. From this perspective, insulin resistant states like metabolic syndrome and type-2 diabetes can be viewed as carbohydrate intolerance, in which a high carbohydrate intake translates to increased serum SFA and therefore increased risk.
In non-athletes we have shown in two studies that low carbohydrate diets containing more than two-fold higher levels of saturated fat actually decrease plasma level of saturated fat. For athletes especially, they are promptly converting dietary saturated fat into carbon dioxide and water (i.e., they are rapidly burning it for fuel). It’s hard to imagine that saturated fat could be harmful when it is not accumulating in the body because of its prompt oxidation.
Stayfitcentral: Tell us about your new book with Dr. Phinney.
Dr. Volek: Steve and I share a common interest in studying low carbohydrate diets. We have both conducted significant research and personally follow a low carbohydrate lifestyle. Steve has considerable clinical experience as well. In regard to clinical applications of low carbohydrate diets, we co-authored ‘The Art and Science of Low Carbohydrate Living’ which was aimed specifically at physicians and health care professionals. However, we are both extremely interested in the use of low carbohydrate diets for athletes as well. So after publishing that book last year we started working on a companion book ‘the Art and Science of Low Carbohydrate Performance’ that addresses the specific needs of athletes and physically active individuals. The key fact underlying this book is that you can train your body to burn fat by simply changing your diet over a period of a few weeks, thereby turning blood sugar and glycogen into secondary fuels. Once you make this transition, you can then train harder, perform longer, and recover faster. This strategy has worked for us and many people we know. More importantly, we have both conducted and published human research that supports this approach, adding to a growing body of literature that now points to the merits of reducing dietary carbohydrates to optimize fat metabolism. We have thus accumulated a unique knowledge base that we want to share so others can experience too.
Stayfitcentra: Thanks very much for your time. I learned a ton and am sure our readers will too.