Zone Living Articles
Q&A with Dr. Barry Sears
You have questions, Dr. Sears has answers. We know it's hard to stay current with everything in the news and what exactly to believe. Leave that to Dr. Sears! Whether its a question about a study in the news, health trend, or something that pertains to your own personal health, this section is devoted to answering these questions. Most likely if you have questions, someone else has them too! The New York Times Recently Published an article that fish oil doesn’t protect against heart disease. What are your thoughts on this? This article was based upon a meta-analysis looking at various studies using fish oil and markers of heart disease. The highest dose of fish oil used in any of these trials was 1,800 mg of EPA and DHA per day, with the majority using around 400 mg of EPA and DHA per day. What this study showed is that when you don't give therapeutic levels of fish oil, you won't see the benefits. You will see no effects on the resolution of inflammation, a driver of heart disease, until you reach about 5,000 mg of EPA and DHA per day. Kombucha is a fermented beverage that has a long tradition of being used in many cultures because of its nutritional benefits and is gaining popularity in the marketplace. It’s thought that its fermentation process results in the production of a large number of healthy bacteria? Do you feel it’s a good aid for gut health? The benefits of Kombucha are believed to come from their levels of probiotics. Probiotics are live bacteria. 99.99% of probiotics are destroyed in the stomach due to its high acidity. The few that survive only pass through the gut acting as target practice for the immune cells that line the gut to improve their recognition of more pathogenic bacteria. Probiotics do not colonize the gut. They have benefits, but those benefits are mild compared to fermentable fiber and polyphenols for gut health. What exactly are the differences between Prebiotics and Probiotics. Is it important to have both in the diet? Probiotics are live bacteria that are unable to colonize the interior of the gut. This means they lack the ability to change the microbial composition of the gut. Prebiotics are fermentable fiber that serve as the food source for the microbes in the gut. Fermentable fiber can significantly change the microbial composition within the gut, thus they are far more important for gut health. Non-starchy vegetables are an excellent source of fermentable fiber. What is bone broth and what are your thoughts on it as a protein supplement? Bone broth is essentially cooking stock. It is made by taking the bones from either chicken or beef, adding vegetables and spices for flavor, and then covering with water and simmering for anywhere from 24-48 hours. Using bone, beef, or chicken broth for cooking is better than using water, but the true nutrition for a meal will come from the protein, carbohydrates, and fermentable fiber that you are adding the broth to. When it comes to bone broth as a protein supplement, there are others that are vastly superior. Bone broth contains primarily collagen which is a poor source of quality protein as well as minerals. When choosing a protein supplement one with milk or whey protein isolates would be more ideal as they richer in essential amino acids whereas collagen is not. What have you been doing to protect yourself against the flu this season. Do you have tips for how to keep your immunity high the rest of the season? Whether you’ve had the chance to get vaccinated for the flu or not, there are things you can do to bump up your immunity. The first would be good hygiene with regards to keeping up on good handwashing, making sure you are getting plenty of rest, and ensuring a healthy diet that doesn't make your immune system have to work even harder. A diet balanced in lean proteins, good fats and colorful carbohydrates primarily from vegetables, is most ideal to avoid overloading your immune system. This is why I think it’s important to follow a strict Zone Diet, coupled with OmegaRx 2 to increase the resolution of existing inflammation and to provide your immune system further capacity to defend you again the flu virus. Let us know in the comments below if you have questions you'd like Dr. Sears to address in his next round of Q&A.{{cta('cd305230-6e34-42f6-9e2c-c2beda556f50')}}
The Importance of Polyphenols in Athletic Performance
Within every cell in our body are ancient bacterial fragments called mitochondria. Essentially, the role of mitochondria is to take the food we eat and turn it into energy (a.k.a ATP). For an athlete, without adequate levels of ATP, muscles can’t contract, nor can they repair the damage done by exercise. The only way to make enough ATP is to make sure that adequate levels of oxygen are getting to the muscle cell and at the same time making sure the mitochondria in the muscle cells are working at peak efficiency to generate as much ATP as possible. Anything that increases ATP production will give the athlete a significant advantage over their competitors. Polyphenols and Performance The role of polyphenols in athletic performance is only now beginning to emerge. Polyphenols operate at several levels including gene activation which leads to increased mitochondrial efficiency and increased blood flow to deliver more oxygen to the mitochondria. In particular, replacing damaged mitochondria while simultaneously replacing them with newly synthesized mitochondria is a key function of polyphenols. Since mitochondria supply 85-95% of the energy to a muscle cell, the more efficient the mitochondria are, the greater the athletic performance. The Impact of Polyphenols on Recovery Times Polyphenols are the chemicals that give fruits and vegetables their color. They are also key components for gut health as they function as the primary guardians of the gut to defend it against pathogenic microbes. However, small levels of polyphenols can also enter into the blood. Once in the blood, they can become gene activators (1). In particular, they activate the gene transcription factors that cause the increased synthesis of specialized proteins. One of these gene transcription factors is Nrf2 known to increase the expression of anti-oxidative enzymes that are a 1000 times more powerful than standard anti-oxidants such as Vitamin C or Vitamin E in reducing excess free radical production. This is important for reducing delayed onset muscle soreness (DOMS). DOMS is the extended muscle pain and soreness due to injury that reduces strength until the muscle is finally healed. That takes time, and that is why you need increased recovery times the more intense you workout. The other gene transcription factor activated by polyphenols is AMP kinase. AMP kinase is the master switch for your metabolism. In particular, it is the key to replacing damaged mitochondria (mitophagy) and simultaneously replacing them with new ones (biogenesis). Since the cells in the body need ATP on a constant basis, this is equivalent to changing tires on your car while driving 60 miles an hour. It is only possible if AMP kinase is working at full efficiency. Another benefit of adequate levels of polyphenols in the blood is to increase blood flow by increasing nitric oxide (NO) production which increases oxygen transfer to the mitochondria for still greater ATP production (2). The mechanism of polyphenol-induced vasodilation appears to be via the enhanced conversion of dietary nitrates (primarily found in green leafy vegetables) into NO. The greater the number of hydroxyl groups on the polyphenol, the more efficient the conversion of dietary nitrate into NO (3). Thus the benefits of taking nitrate supplements such as beetroot juice (4) can be greatly enhanced in the presence of high levels of polyphenols. Why You Need Adequate Intake of Polyphenols for Performance This is all great news for the athlete. The bad news is that the bioavailability of polyphenols into the blood is low, and even if they enter the blood they are rapidly removed making their lifetime in the blood very short. This means to get the full benefits of polyphenols for sports performance, they have to be taken at high concentrations on a continual basis to maintain improved blood flow and optimal ATP production. Since the levels of polyphenols in fruits and vegetables is low (0.1 to 0.2% by weight), you would have to consume a minimum of 10 servings of fruits and vegetables per day to obtain the minimum levels of polyphenols required for enhanced sports performance. For many athletes, that sounds like Mission Impossible. Purification of Polyphenols Fortunately, polyphenols can be purified to high concentrations as extracts. Supplementation with polyphenol extracts may potentially achieve adequate levels of polyphenols in the blood to increase ATP production and decrease delayed muscle soreness. Not All Polyphenols Are the Same There are more than 8,000 known polyphenols, all different in structure. The most effective polyphenols fall into a general classes known as flavonoids. These polyphenols have a fused phenol ring structure that provides a unique spatial configuration to enhance their action to activate gene transcription factors. Furthermore, the number of hydroxyl groups in its structure determines the bioavailability of the polyphenol. The one group of flavonoid polyphenols that have the greatest bioavailability is delphindins, and they appear to be the only type of polyphenol that can be absorbed intact by the body (5). A rich source of delphinidins is blueberries. In particular the Maqui berry grown in the Patagonia region of Chile has the highest known concentration of delphinidins. In addition, the most studied flavonoid polyphenol for increasing blood flow are those from cocoa (6-8). Thus, combinations of Maqui and cocoa polyphenol extracts may provide the greatest potential for maximum impact in sports performance. How Many Polyphenols Do You Need For Performance? A lot. You need probably at least 1,000 mg of polyphenol extract per day. Furthermore, that total amount should also be spread evenly throughout day to maintain adequate levels of polyphenols in the blood. Frankly, no one is going to be taking capsules all day long to achieve that goal. This is why the most realistic way is the use of food products (bars) that not only supply necessary nutrients (you have to eat) to maintain stable blood sugars levels, but also supply the necessary levels of proven polyphenol extracts to constantly activate the genes needed for optimal athletic performance.{{cta('a9e96fff-3523-4d72-b761-29f9ef2a1279')}}References: Sears B. The Mediterranean Zone. Ballantine Books. New York, NY (2014) Lundberg JO et al. “Strategies to increase nitric oxide signaling in cardiovascular disease.” Nat Rev Drug Dis 14: 623-641 (2015) Rocha SA et al. “Dietary nitrate in nitric oxide biology.” Curr Drug Targets 12: 1351-1363 (2011) Wylie LJ et al. “Beetroot juice and exercise: Pharmacodynamic and dose-response relationships.” J Appl Physiol 115: 325-336 (2103) Matsumoto H et al. “Orally administered delphinidin 3-rutinoside and cyanidin 3-rutinoside are directly absorbed in rats and humans and appear in the blood as the intact forms.” J Agric Food Chem 49: 1546-1551 (2001) Schroeter H et al. “(-)-Epicatechin mediates beneficial effects of flavanol-rich cocoa on vascular function in humans.” Proc Natl Acad Sci USA 103: 1024-1029 (2006) Heiss C et al. “Endothelial function, nitric oxide and cocoa flavanols.” J Cardiovasc Pharmacol 47 Suppl 2:S128-135 (2006) Desideri G et al. “Benefits in cognitive function, blood pressure, and insulin resistance through cocoa flavanol consumption in elderly subjects with mild cognitive impairment: the Cocoa, Cognition, and Aging (CoCoA) study.” Hypertension 60:794-801 (2012)
Gut Health Explained
Atrip down your local dairy aisle and you may be surprised to find the word prebiotic beginning to appear next to probiotic on several labels. Often these words or concepts are introduced to us in the marketplace and while they may become familiar sounding over time, chances are we’re still at a loss to explain how they improve our health (unless you read our blogs of course!). Here we’ll dive into the topic of gut health, defining some of the key terms and our recommendations for a healthy gut. What is Gut Health? When we hear the word “gut” we might initially think stomach or that butterfly feeling we get when we’re nervous or anxious, but the subject is incredibly complex and evolving each day. In the simplest form, gut health encompasses our entire digestive system starting with where food enters our mouth and where it exits. You can see why this topic doesn’t come up at dinner parties! We may not think much about the process of eating, unless of course it doesn’t agree with us, but so much happens within that 25-30 hour window from when we first smell and ingest a food to its excretion from the body. The gastrointestinal (GI) tract, or tube that runs from our mouth to large intestine, is lined with mucus and trillions of microorganisms (a.k.a microbes) that thrive and metabolize the foods we eat. The majority of these reside in our large intestine or colon. We now know that a strong link exists between the microbes (bacteria being a type of microbe) that inhabit our gut and our risk for disease. This is why gut health is such a hot topic. What are Probiotics? Probiotics are live bacteria or yeast found in food products that help to promote the maintenance of the beneficial bacteria in our gut1. They aid in keeping the balance between both the good and bad bacteria. This is one reason their use is suggested after we go on antibiotics. In an effort to get rid of the bacteria causing us to be ill, antibiotics can’t discriminate and wipe out both the good and bad. Probiotics such as those found in kefir or yogurt help to provide a stimulus to the immune cells that line the gut to prevent potentially bad bacteria from trying to get into the gut while good bacteria are being re-established. Think of them as immune boosters. What’s interesting to note, is that it can take almost eight weeks after antibiotic use for the number of bacteria to rebound to baseline2,3, but weeks to months for the diversity of that bacteria (meaning the different types) to return4. This just stresses the importance of not overusing antibiotics as we are still learning about how their use disrupts the balance of bacteria in the gut5 and the long-term implications on our health. Common Probiotics Found in Foods: Lactobacillus, Bifidobacterium, Lactococcus, Enterococcus, Bacillus, Saccharomyces. What are Prebiotics (a.k.a Fermentable Fiber)? Prebiotics are the food that stimulates the growth of good bacteria in our gut. They come from non-digestible carbohydrates and are found naturally in foods like leeks, asparagus, artichokes or additives such as inulin or oligosaccharides. Since these aren’t fully digested they are able to reach the colon where they are fermented by good bacteria. This is why you may hear them referred to as fermentable fiber. The result of this fermentation is that it produces beneficial changes in the composition or activity of the bacteria helping to improve our overall health and well-being1,5. All prebiotics are fiber, but not all fiber is a prebiotic5. One of the primary end products of fermentable fiber is short-chain fatty acids. These have a profound impact on our health including maintaining a strong barrier between the microbes in the gut and limiting their potential entry into our blood. If you don’t have enough fermentable fiber in the diet, you will have a deficiency in short-chain fatty acids. This can lead to a leaky gut, where you get holes in the lining of the gut barrier and bacteria begin to leak into the blood, creating an assortment of health problems. How to Optimize Gut Health Gut health requires two essential agents: fermentable fiber to supply energy to the microbes in the gut (primarily in the colon) as well as adequate levels of polyphenols. Think of the polyphenols as gardeners that help to promote good bacterial growth and inhibit the bad. Without adequate levels of either in the diet, the result is increased gut inflammation and an increase in leaky gut which can cause inflammation in the body. 3 Ways to Support a Healthy Gut 1. Eat Fermentable Fiber (Prebiotics) Not all fiber is fermentable by the bacteria in the gut. In fact, only about 10-15% of the stated fiber content of a food is fermentable. Since you need about 6 grams of fermentable fiber per day, this means you should be consuming about 40 grams of total fiber per day. Most Americans are nowhere close to that level, but following the Zone helps to get you there. The best sources of fermentable fiber include non-starchy vegetables (such as onions, garlic, asparagus, and artichokes, selected fruits (berries and apples), legumes (beans and lentils), and nuts (almonds, walnuts, etc.). These are all rich in both fermentable fiber and polyphenols necessary for optimal gut health. The vegetables are harder to digest if you don't have adequate diversity in your gut bacteria. 2. Take Your Polyphenols Polyphenols represent the primary defense mechanism to prevent bad bacteria from inhabiting the gut while increasing the production of the good bacteria. They also have gene activation properties that can increase the expression of anti-oxidative, anti-inflammatory, and anti-aging gene products. The more colorful the carbohydrates, the higher the levels of polyphenols. Most Americans get their polyphenols primarily from coffee. Unfortunately, the polyphenols in coffee or tea are not nearly as active as are the polyphenols found in vegetables or fruits. 3. Add Your Omega-3s The omega-3 fatty acids EPA and DHA are the starting point for the production of hormones that reduce inflammation in the gut and prevent the development of a "leaky gut". Gut-derived inflammation is a primary source of inflammation for the rest of the body. Ideally consuming a minimum of 2.5 grams of EPA and DHA per day can help maintain a healthy gut. The average American consumes about 5% of that suggested level. Buyer Beware Diets that strictly limit the amount of carbohydrates consumed can reduce the diversity of bacteria in the gut since they restrict fermentable fiber and polyphenols. When choosing foods it’s important to think about how the foods you eat help to nourish and support a healthy gut. By following the Zone Diet you’ll consume the right type and amount of carbohydrates to achieve the optimal levels of both fermentable fiber and polyphenols. {{cta('daffa570-1055-4766-af51-e09d66a17e47')}} References: 1. Markowiak P, Śliżewska K. Effects of Probiotics, Prebiotics, and Synbiotics on Human Health. Nutrients. 2017 Sep 15;9(9). pii: E1021. doi: 10.3390/nu9091021. Review. 2. F. Fouhy, C.M. Guinane, S. Hussey, R. Wall, C.A. Ryan, E.M. Dempsey, B. Murphy, R.P. Ross, G.F. Fitzgerald, C. Stanton, and P.D. Cotter, 2012. High-throughput sequencing reveals the incomplete, short-term recovery of infant gut microbiota following parenteral antibiotic treatment with ampicillin and gentamicin. Antim. Agents Chemother. 56:5811-5820 3. Grazul H, Kanda LL, Gondek D. Impact of probiotic supplements on microbiome diversity following antibiotic treatment of mice. Gut Microbes. 2016;7(2):101-14. 4. Langdon A, Crook N. The effects of antibiotics on the microbiome throughout development and alternative approaches for therapeutic modulation. Genome Med. 2016; 8: 39. 5. Gibson G.R., Probert H.M., van Loo J., Rastall R.A., Roberfroid M.B. Dietary modulation of the human colonic microbiota: Updating the concept of prebiotics. Nutr. Res. Rev. 2004;17:259–275.
What Is the Ketogenic Diet and How Does It Compare to the Zone Diet?
Over the past few months we’ve received a number of inquiries regarding Dr. Sears’ stance on the Ketogenic Diet and how it relates to the Zone in terms of health and weight loss. Is this just the next diet craze or is it as good for weight loss and health as it’s touted to be? What Is the Ketogenic Diet? The ketogenic diet is a high-fat, low carbohydrate diet consisting of approximately 75% fat, 20% protein and 5% carbohydrate. Compare this to the Zone which is moderate in these macronutrients and supplies 30% fat, 30% protein and 40% carbohydrate as total dietary calories. The Ketogenic Diet is based on getting the body into a state of ketosis (hence “keto”). Ketosis is a back-up metabolic system used to provide the brain with an energy source, called ketones, if glucose isn’t available or if blood levels fall too low. What’s the Buzz About? The popularity in the Ketogenic Diet stems from the quick weight loss it produces and its perceived health benefits. The diet is thought to increase the body’s ability to burn stored body fat and lower insulin levels. It’s important to note that the weight loss that stems from this diet isn’t necessarily fat loss, despite fat being the preferred/primary fuel on this eating plan. Weight Loss from the Ketogenic Is Not From Stored Body Fat In general, when we lose weight, it results from one of three factors: the loss of retained water, loss of muscle mass or loss of stored body fat. The ideal scenario would be to lose stored body fat. Ketogenic diets can promote an initial loss of retained water that comes with the depletion of glycogen (storage form of glucose). This is because stored glycogen retains significant levels of water. As the glycogen levels are reduced (due to limited carbohydrates in the diet), the retained water associated with that stored glycogen is also rapidly lost through increased urination. Although the loss of weight on a scale can be considerable in the first few days of a ketogenic diet, it will result in little loss of stored body fat. The loss of stored body fat only comes with significant calorie restriction as the body has many biological processes that help us to preserve it. Why You Don’t Lose Fat on the Ketogenic Diet Ketogenic diets are high in fat, which means the blood levels of fat will also be increased. As the availability of glucose in the blood decreases and the availability of fat increases, the metabolic flexibility (inherent in muscle cells) switches to using circulating fat as the preferred source of fuel for energy production (a.k.a. ATP), instead of glucose. This leads to the misconception that by getting into a state of ketosis you burn stored body fat. Instead, it is that the higher levels of dietary fat entering the blood stream are now becoming the preferred source of energy. Furthermore, a ketogenic diet being low in carbohydrates lowers insulin levels so less of that circulating fat can be stored in adipose tissue for long-term storage. Protein can also increase insulin levels resulting in circulating fat being transported into the adipose tissue for storage. This is why eating a high-fat diet containing excess calories, but with adequate levels of protein would not result in any fat loss, even though the carbohydrate content of such a diet can be very low. Hormonal and Physiological Changes that Take Place on Long-term Ketogenic Diets What is known from clinical studies is that significant hormonal changes take place on ketogenic diets and it’s not necessarily for the better. Here is a snap shot of the hormones impacted when following the diet long-term. Hormonal Changes Insulin1 Thyroid 2 Cortisol 2 Testosterone 3,4 Physiological Changes Immune Function 5 Mental and Physical Fatigue Due to Low Blood Sugar 6 Gut Dysbiosis 7,8 Since the ketogenic diet is limited in carbohydrates, it will not supply enough fermentable fiber for gut health. This lack of fermentable fiber will reduce the production of short-chain fatty acids (SCFA) that are required for maintaining the integrity of the mucus barrier and tight junction of the mucosa as well as increasing the production of T-regulatory cells. The end result is a greater likelihood of metabolic endotoxemia which can lead to weight regain. Loss of Muscle Mass 9 Stimulation of protein synthesis requires the combination of insulin (to drive amino acids into the muscle cell) and testosterone (to activate the receptors that signal for the stimulation of new muscle formation. Both hormones are decreased in ketogenic diets thus making it difficult to maintain muscle mass. Why the Zone Diet Is Preferable to the Ketogenic Diet A few years back, we set out to test how the Zone Diet compared to a Ketogenic Diet. This study kept both the protein and total calorie intake constant between a ketogenic diet and the non-ketogenic Zone Diet10. It controlled the diet for the first six weeks by supplying all the food to the subjects. These were calorie restricted diets (1,500 calories per day) to ensure that there was a sufficient calorie deficit to determine the effect of the two diets on loss of stored body fat, which can be only be achieved if a calorie deficient is maintained for long enough period of time. In the first three weeks of the study, the weight loss of the non-ketogenic Zone Diet and the ketogenic were essentially the same. However, in the second three-week period, the weight loss on the non-ketogenic Zone diet was greater than compared to the ketogenic diet. The same was true for fat loss. Even though it was a calorie restricted diet, there was no change in the fat-free (i.e. muscle mass) mass of either group during the six-week period indicating that the protein intake (which was equal in both diets) was sufficient to spare the loss of muscle mass. The AA/EPA ratio in the blood is indicative of inflammation. On the ketogenic diet, this inflammatory marker doubled during the six-week period of the study, whereas there was slight lowering on the non-ketogenic Zone Diet. Furthermore, mental state and exercise capacity of the subjects following the non-ketogenic Zone Diet improved during the study when compared to the subjects following the ketogenic diet. This study presented evidence that there were no advantages of a ketogenic diet compared to one with equal protein, calories, and higher carbohydrate and lower fat content such as the Zone Diet. In addition, the study suggested that a ketogenic diet significantly increases inflammation in a relatively short period of time compared to non-ketogenic Zone Diet. Summary Although initial weight loss (but not necessarily fat loss) on a ketogenic diet may be higher compared to a non-ketogenic diet, there are no long-term differences in overall weight loss. This may be due to the changes in hormonal responses induced by a ketogenic diet. Furthermore, the hormonal and inflammatory changes induced by a ketogenic diet may have significant adverse health consequences as suggested in epidemiological studies. Fat loss is only achieved by calorie restriction and can be maintained only if the diet used is one that is without hunger or fatigue so that the fat loss can be maintained for a lifetime. This can be achieved by a calorie-restricted diet that is adequate in protein to prevent the loss of lean muscle mass, supplies adequate levels of carbohydrates to reduce the generation of ketone bodies and promote gut health, maintains adequate levels of blood glucose for the brain, and finally contains a low level of dietary fat to encourage the use of stored fat for energy by the rest of the body. That’s the promise of the Zone Diet.{{cta('cd305230-6e34-42f6-9e2c-c2beda556f50')}}References: Foster GD, Wyatt HR, Hill JO, Makris AP, Rosenbaum DL, Brill C, Stein RI, Mohammed BS, Miller B, Rader DJ, Zemel B, Wadden TA, Tenhave T, Newcomb CW, and Klein S. “Weight and metabolic outcomes after 2 years on a low-carbohydrate versus low-fat diet: a randomized trial.” Ann Intern Med 2010 153:147-57 Ebbeling CB, Swain JF, Feldman HA, Wong WW, Hachey DL, Garcia-Lago E, and Ludwig DS. “Effects of dietary composition on energy expenditure during weight-loss maintenance.” JAMA 2012 307:2627-2634 Anderson KE, Rosner W, Khan MS, New MI, Pang SY, Wissel PS, and Kappas A. “Diet-hormone interactions: protein/carbohydrate ratio alters reciprocally the plasma levels of testosterone and cortisol and their respective binding globulins in man.” Life Sci. 1987 40:1761-1788. Lane AR, Duke JW, and Hackney AC. “Influence of dietary carbohydrate intake on the free testosterone: cortisol ratio responses to short-term intensive exercise training.” Eur J Appl Physiol 2010 108:1125-1131. Sephton SE, Dhabhar FS, Keuroghlian AS, Giese-Davis J, McEwen BS, Ionan AC, and Spiegel D. “Depression, cortisol, and suppressed cell-mediated immunity in metastatic breast cancer.” Brain Behav Immun 2009 23:1148-1155. White AM, Johnston CS, Swan PD, Tjonn SL, and Sears B. “Blood ketones are directly related to fatigue and perceived effort during exercise in overweight adults adhering to low-carbohydrate diets for weight loss: a pilot study.” J Am Diet Assoc. 2007 107:1792-1796. Duncan SH, Belenguer A, Holtrop G, Johnstone AM, Flint HJ, and Lobley GE. “Reduced dietary intake of carbohydrates by obese subjects results in decreased concentrations of butyrate and butyrate-producing bacteria in feces.” Appl Environ Microbiol 2007 73:1073-1078. Cani PD, Amar J, Iglesias MA, Poggi M, Knauf C, Bastelica D, Neyrinck AM, Fava F, Tuohy KM, Chabo C, Waget A, Delmée E, Cousin B, Sulpice T, Chamontin B, Ferrières J, Tanti JF, Gibson GR, Casteilla L, Delzenne NM, Alessi MC, and Burcelin R. “Metabolic endotoxemia initiates obesity and insulin resistance.” Diabetes. 2007 56:1761-1772. Fujita S, Rasmussen BB, Cadenas JG, Grady JJ, and Volpi E. “Effect of insulin on human skeletal muscle protein synthesis is modulated by insulin-induced changes in muscle blood flow and amino acid availability.” Am J Physiol Endocrinol Metab 2006 291: E745–E754. Johnston CS, Tjonn SL, Swan PD, White A, Hutchins H, and Sears B. “Ketogenic low-carbohydrate diets have no metabolic advantage over nonketogenic low-carbohydrate diets.” Am J Clin Nutr 2006 83:1055-61.