As an increasing number of studies mount in favor of low carb high fat (LCHF) diets, Dr. Stephen Phinney has become renowned for his extensive research expertise on how and why these plans are so effective for weight loss. With an M.D. from Stanford University, PhD in Nutritional Biochemistry from MIT and post-doctoral training at the University of Vermont and Harvard, he's an acclaimed professor and best-selling co-author of books such as "The Art and Science of Low Carbohydrate Living: An Expert Guide to Making the Life-Saving Benefits of Carbohydrate Restriction Sustainable and Enjoyable."
In an exclusive interview on Monday, Dr. Phinney explained just how low carb diets work - and how you can benefit. He specializes in ketogenic diets, which involve restricting carbohydrates while boosting fat intake and keeping protein intake moderate. But are these diets for everyone?
"Obviously at this juncture, we are not recommending that everyone should go on a ketogenic diet," qualified Dr. Phinney. "But everyone should markedly reduce their intakes of sugars (sucrose, glucose, fructose) and refined carbs."
And in an era where obesity and associated conditions such as type 2 diabetes and metabolic syndrome now rank as epidemics, this physician believes LCHF diets can provide much-needed help. "Given both the healthcare costs and the medical risks associated with type 2 diabetes and metabolic syndrome, plus the immediate improvements (if not complete remission) in these diseases with a well-formulated ketogenic diet, this diet should be the primary (aka first) therapy that doctors and dietitians recommend," he stated.
In elementary school through college, students typically are taught that carbohydrates such as fruit juice and whole grains are essential for energy and health. But Dr. Phinney challenges that conventional wisdom.
"The concept that humans 'need a certain amount of dietary carbs for proper function of the body' has no basis in science," he told me. "It is a myth perpetuated by the USDA and the dietetic establishment."
In one study challenging that "myth," two individuals consumed no carbohydrates for a year with no negative consequences while closely observed in a hospital. In another study, researchers "infused insulin into obese humans in fasting ketosis and demonstrated that they had no symptoms of hypoglycemia despite blood sugar levels that should have caused them to be in a coma" noted Dr. Phinney.
That latter study demonstrated that our bodies function just fine on ketones no matter what your blood glucose level. But what precisely is a ketogenic diet, and how does it work for weight loss while enhancing parameters of health such as cholesterol level and reduced risk of type 2 diabetes?
Dr. Phinney defines a ketogenic diet as one with total carbohydrates between 10 to 50 grams daily. The rest of the diet consists of fats (example: avocado, nuts and olive oil) and protein (example: chicken, cheese. beef, eggs, pork and turkey). Add to that copious amounts (5 servings per day) of non-starchy vegetables to provide important minerals such as potassium and magnesium.
"People on a well-formulated ketogenic diet maintain normal blood sugar levels because their bodies' learn to use much, much less blood sugar," Dr. Phinney explained to me. Morever, as their bodies become keto-adapted and burn fat for energy, "the liver can make enough glucose via gluconeogenesis to supply that small amount of blood sugar that is actually consumed."
And for those who wonder why ketogenic diets haven't come to general attention until recent years, they actually have. But most consumers know them under a brand name: Atkins. It was Dr. Robert Atkins who is credited with focusing on high fat low carb ketogenic diets as the best approach to weight loss.
Dr. Phinney, along with co-authors Dr. Jeff Volek and Dr. Eric Westman, also co-authored "New Atkins for a New You: The Ultimate Diet for Shedding Weight and Feeling Great." He's conducted additional studies with Dr. Volek on the effects of keto-adaptation.
Their studies are extensively cited in the latest book documenting the benefits of low carb high fat diets: "The Big Fat Surprise: Why Butter, Meat and Cheese Belong in a Healthy Diet." In it, author Nina Teicholz compares their ketogenic discoveries about how the body shifts to burning fat stores to a hybrid car.
"As for the hybrid car analogy, I think what Nina was getting at was that when glucose is made into lactate (normally considered harmful) by red blood cells or intensely exercising muscle, the keto-adapted person's liver avidly takes it up and makes it back into glucose," clarifies Dr. Phinney. In turn, the glucose is released and recycled.
Critics of the Atkins diet and other high fat low carb ketogenic diets often complain about what has become known as "Atkins flu" symptoms: Headaches, fatigue, dizziness. The reason for these side-effects: The kidney's rate of sodium excretion is accelerated as a result of nutritional ketosis.
Although the increase in the rate of sodium excretion benefits those with high blood pressure or fluid retention, it "also tends to reduce the amount of sodium that is necessary to maintain normal circulation," explained Dr. Phinney. To compensate, in nutritional ketosis the body lowers the amount of fluid in the bloodstream.
Dizziness, fatigue and constipation sometimes result because of this reduced blood volume. However, the prescription for those symptoms is inexpensive and easy.
"The 'solution' (pun intended) is to add a modicum of sodium to that minimal level preached by the salt mavens," Dr. Phinney told me. That means sipping two cups of broth or bouillon which, combined with modest dietary salt intake, yields five grams of sodium daily.
That level of sodium helps to avoid side effects while dieters maintain nutritional ketosis. And for those who question how long it is safe to remain in ketosis, Dr. Phinney points to cultures which have based their well-being on maintaining this state for thousands of years .
"Whole cultures thrived for millennia in nutritional ketosis," says Dr. Phinney. Among them: The Inuit, the Massai and the nomadic Native Americans who hunted the buffalo." Both he and his colleague Dr. Volek have stayed in nutritional ketosis for years.
As for those who contend that it's risky to cut carbohydrates and boost fats for that long, Dr. Phinney asks the rhetorical question: "What risks?" He cites benefits including improved good (aka HDL) cholesterol levels, reduction in inflammation and lower levels of saturated fats in the blood.
In recent years, two very different additional uses of the ketogenic diet have surfaced. The first use focuses on easing the symptoms of conditions such as multiple sclerosis. The other purpose: Improving performance in athletes.
With regard to using a ketogenic diet to battle disease, Dr. Phinney explains that "many causes of seizures, many forms of cancer, and Alzheimer's disease are associated with or promoted by inflammation. I think that we will increasingly monitor blood or breath ketones to guide patients to their personalized carb intakes to achieve optimum anti-inflammatory results."
In particular, an increasing number of physicians are using ketogenic diets to combat epilepsy. In "Ketogenic Diets," four medical specialists from John Hopkins explore how to customize high fat low carb diets for seizure control as well as other conditions such as brain tumors, diabetes, autism, migraine and heart disease.
With regard to specialized uses of ketogenic diets, Dr. Phinney's research long ago demonstrated the potential for improved performance for keto-adapted athletes. In doing so, he challenged the standard convention of carb-loading for athletes.
Now his colleague Dr. Jeff Volek is conducting a study "of ultra-marathon runners who have chosen to follow either a high carb diet or a low carb diet." The study will be completed in upcoming months.
"Early data show that the keto-adapted runners are able to utilize mostly fat when running at up to 80% of their maximal aerobic power. This will completely re-write the 'rules' about fat use during exercise," predicted Dr. Phinney.
He and Dr. Volek have authored a book containing their research and studies on high fat low carb diets for athletes: "The Art and Science of Low Carbohydrate Performance." He notes that individual athletes continue to prove the merits of ketogenic diets. Example: "Low carb athlete Sami Inkinen at age 39 recently won the Wildflower Triathlon against a field of almost 1500."
In addition, four of the top six men and women at last year's Western States Endurance Run (100 miles on mountain trails from Lake Tahoe to Auburn) followed low-carb diets. Moreover, earlier this year at age 36, low carb dieter and bronze medalist winner Bode Miller became the oldest Olympic skiing medalist.
And to those who still fear consuming foods like butter cheese, pork, and beef, Dr. Phinney points to the laboratory results of those who eat saturated fats during a ketogenic diet. "If blood levels of saturated fats (which is the only place where saturated fat levels have been scientifically linked to heart disease and diabetes) go down on a well-formulated ketogenic diet independent of saturated fat intake, what is there to fear about eating saturated fats?"
His prediction: "Remember the folks back in the 1960s who used to argue that seat belts would kill people because they couldn't get out of burning cars? Looking back a few years from now, we'll find fear of saturated fats equally laughable."