Keto 101

The ketogenic or keto diet is not new. It is not a fad. If your goal is reversal of chronic disease,  restoration of metabolic health, and/or weight loss, the ketogenic diet is your best option.

Spoiler: there are no definitive studies in the scientific literature that prove that a particular diet is the best. My reason for backing this dietary approach is based on extensive review of the available scientific literature,  personal medical experience and belief in the diet’s physiologic mechanism of action. The ketogenic diet relies on extreme carbohydrate restriction to facilitate a metabolic shift from burning glucose for energy to burning fat.

Energy

Your body needs fuel. Humans are like a hybrid vehicle; they can run on glucose or fat. The vast majority of Americans run on glucose. Glucose is a simple sugar. Table sugar (sucrose), for example is one molecule of glucose and one of fructose (fruit sugar) bound together. Once ingested sucrose is quickly broken down into these two components.  Carbohydrates are simply longer chains of glucose. When digested, they break down into individual sugar molecules. The glucose is quickly absorbed into the bloodstream and can be used directly as fuel, or stored either as glycogen or converted into fat. 

Under normal circumstances blood glucose levels are tightly regulated. Turns out that there’s only 1 teaspoon (5 grams) of glucose dissolved in your entire blood volume.  Blood sugar that is too high (hyperglycemia) for too long is toxic to a variety of tissues. This is diabetes. Blood sugar that is too low (hypoglycemia) can result in coma, seizures or even death. Insulin functions as the traffic cop. When you ingest a meal with a large load of carbohydrates your blood sugar spikes which in turn causes your pancreas to secrete insulin. Insulin drives the glucose into your cells for direct use or storage. Since there is an abundance of fuel, insulin also signals your fat tissue (adipose) to shut down the fat burning process. No need to burn precious fat stores in the presence of excess glucose.

This is the key to understanding how the ketogenic diet works. Carbohydrate ingestion spikes blood glucose, which spikes insulin, causing  the body to function in fuel storage mode.

By limiting carbohydrate intake, your blood sugar levels remain stable and insulin levels are low. In doing so your body shifts to burn fat for fuel. Low insulin levels signal the adipose tissue that it’s “ok” to burn fat for fuel. It takes a little while for the metabolic machinery to get fully ramped up to do this efficiently which is why people don’t feel well during the first week or so of the diet. Once you are “fat adapted” your body can easily derive all of its needed energy from existing fat stores or ingested fat.

Ketones

Ketones  are small molecules that are a by product of fat metabolism (oxidation). If you’re burning fat for fuel, you’re making ketones hence the name of the diet. This results in a unique circumstance in that you can prove you’re doing the diet correctly by measuring your ketones. Urine test strips are readily available at any pharmacy. If your urine turns the strips purple - you’re burning fat for fuel and making ketones. There are also simple ways to test for ketones in the blood or breath. It is certainly not a requirement to test for ketones but it is an option if you’re not making headway.

Ketogenic Diet

Limit carbohydrate intake to 20 grams or less per day. Protein intake is moderate. Fat intake is high. To do this you need a clear understanding of the macronutrient content of different foods. Macronutrients are carbohydrates, protein and fat. 

Carbohydrates

Carbohydrates are foods that are digested into sugars. Table sugar, bread, rice, pasta, potatoes, beans, baked goods, fruit, the list goes on. From the neck down all of these foods are the same: glucose. Take a look at the included chart to get an idea of the carb content of common foods. Carbohydrate is the only macronutrient that is not essential. There are essential amino acids (building blocks of proteins) and there are essential fats. There are no essential carbohydrates. A brief word about fruit. Nearly everyone considers fruit healthy and natural. However, if your goal is to eliminate carbs, you have to get rid of the fruit too.

You might ask “why don’t you get hypoglycemia (low blood sugar) if you’re not eating carbs?” Your body easily manufactures glucose in the liver in times of need. This is called gluconeogenesis. It is a process driven by demand. Furthermore, in the presence of circulating ketones, the body tolerates lower blood glucose levels because the ketones serve as an alternate fuel source.

I’ve included a link to a printer friendly carbohydrate chart to see the carb content of various foods.

Protein

Proteins are chains of amino acids. Some essential amino acids must be obtained in the diet since they can’t be manufactured in the body. Muscle and bone are the most prominent forms of protein. Protein intake on a ketogenic diet is considered “moderate”. You’ll see various recommendations about the exact quantity. Roughly 1 to 1.5 grams of protein per pound of lean body weight. There’s a claim in the keto community that too much protein will “kick you out” of ketosis because it promotes gluconeogenesis. Again, I believe this process is driven by demand.

The good news is that your options for protein are wide open. Beef, chicken, pork, seafood, eggs, cheese, bacon, sausage, game, among others.

Myth busters: Eggs don’t raise your cholesterol. Red meat doesn’t cause heart disease or cancer. Bacon won’t “clog” your arteries.

These protein sources, together with an appropriate amount of fat are uniquely satiating. They satisfy hunger and keep you feeling full.

Fat

Fat gets a bad rap. Unfortunately the same word to describe a type of body tissue is also used to describe a macronutrient. In addition, it is known that fat is more calorie dense than either carbs or protein. 9 calories per gram of fat and 4 calories per gram or protein or carbohydrate. Because of this the calorie counters have told us to avoid fat because it will make us fat. Worse still is that we’ve been told that fat will “clog our arteries” and lead to a heart attack. There isn’t good evidence that dietary fat leads to heart disease. This “diet-heart” hypothesis was proposed in the late 1950’s based on weak, poorly done science. Unfortunately it has become such a well accepted belief that it is extremely difficult to convince people otherwise.

Fat intake on a ketogenic diet is high. Roughly 80% of calories should be from fat. It is important to choose “healthy” fats. For years we’ve been told that the various vegetable oils (seed oils) which are high in polyunsaturated fats that are “heart healthy”.  Margarine is better than butter. Really?! Fake butter made in a chemistry lab is better? This is a topic for another day but suffice it to say - avoid seed/vegetable oils: corn, soy, peanut, canola, vegetable, etc… Choose olive, coconut, avocado oils. Butter, ghee, lard and tallow are back on the menu.