It goes by a many different names – keto, ketosis, Atkins, HFLC (high fat, low carb), paleo (to a certain extent) – but they all refer to the same thing. It’s a way of eating that implies that eating fat is not only healthy for you, but far more so than the conventional “wisdom” that eating tons of grains and starchy foods.
As a society we’re warned against the dangers of ingesting too much fat, too much sugar, etc. It wasn’t until recently that modern research caught up with the nonsense of the past and has shown us that butter, fat, and animal proteins are healthy and should make up the bulk of our diet, rather than the highly processed breads, sugars, and grains we’ve had pushed onto us from the government and antiquated nutrition science.
Right, so preamble out of the way – what is ketosis?
Strictly speaking, your body has two different types of metabolism. One is glycolysis, in which carbs are broken down into energy for your body to use. In this model, excess carbohydrate is stored in muscle and in the liver as glycogen, to be used primarily in energetic activity, like biking or simply moving around the office. Your brain uses about 100 grams worth of carbohydrate a day, just by itself, and as I said before, your body can store a certain amount, based on body size and muscle density. The rest is converted into fat, which is bad. In addition, the more you flood your bloodstream with glucose, the more insulin is needed to shuttle the sugar where it needs to go. As insulin tries to do its job, your body becomes resistant, meaning more insulin is needed each time you eat sugar. This chronic state of high insulin and high insulin resistance is called diabetes (well, type 2 diabetes), and is a state that causes problems in very nearly every facet of your biological and mental functioning.
Ketosis is the metabolic state in which your body burns fat instead of carbs, essentially. The process is, in a nutshell, that when your body is out of stored glycogen and has scoured dietary glucose from your bloodstream, the breakdown of triglycerides begins. The fats break down into ketone bodies, which become the primary source of energy for most of your functioning (again, the brain will ALWAYS need glucose, but your body can create enough through a process called gluconeogenesis, which is to say it creates glucose from fat or protein).
Any diet that is under 100 grams of carbs a day will be ketogenic, that is, ketone-creating, but for most people to truly see results from low carb eating, a restriction to under 30 grams a day is generally necessary, at least for the first two weeks to a month. During this time, the body switches its metabolism to one that functions primarily on fat, both stored and dietary, and for at least some of this time, it’s a drag. Reduced mental clarity, significantly reduced ability to perform athletic activity, stomach issues, headaches, and irritability are all likely symptoms, and can last anywhere from 1 week to a month, dependent on how heavily you have used sugar in the past. Despite what anyone says about this being “toxins leaving the body”, it breaks down to the simple truth that sugar is an addictive substance, and reducing the amount you eat causes withdrawal and all the wonderful glitches with which it comes. Anecdotally, friends who have cut carbs and also at one point stopped smoking have said that it can be very similar.
This is essentially the most basic science behind ketosis. When your body is in glycolysis, extra blood sugar is shuttled into fat cells and stored, which is awful, creates insulin resistance, and ugly fat. There’s nothing essentially wrong with glycolysis – plenty of healthy people have metabolisms that are glucose-driven, particularly athletes. From a starting point of ill health, though, getting control of your carb intake is crucial, and most people succeed in losing weight and keeping it off, once they know the actual reasoning behind low carb dieting. Ketosis encourages the body to burn fat preferentially, increases insulin sensitivity (particularly in conjunction with muscle-building strength training, but that’s another post), and keeps you sated longer. This is because fat and protein take far longer to digest than carbs, particularly empty carbs like highly refined sugar and flour, and that’s without even beginning to get into the hormonal rampage that is high fructose corn syrup or processed fruit syrups like agave.
How to start? Well, again, another post, but the most basic macro nutrient (that is, protein, carbs, and fat) breakdown is something like 5% carbs, 35% protein, 60% fat. My next post will deal with healthfully entering ketosis and how to maintain that metabolism.