In What’s in a Carbohydrate? post, we looked at carbohydrate metabolism and how the human body efficiently uses sugars as a main source of energy. For the keto diet, the method is to train your body to use a different avenue for your energy source, often for the purpose of weight loss and health. By switching to a metabolic route that utilizes fat stores,
Ketones are another source of energy that are sourced in-house, as in via your liver. To understand this route, ketosis falls more under the realm of lipid or fat metabolism. In the keto diet, when carbohydrates and blood glucose levels don’t match the need of the body (or for a diabetic’s case, insufficient insulin to convert blood glucose to sugar), the body metabolizes fat stores instead. These fats are converted through a series of events such as beta-oxidation and ketogenesis, eventually creating acetyl CoA (which is the event called “ketosis”). This acetyl CoA enters the Citric Acid Cycle, just like the acetyl CoA did when it originated from carbohydrates.
From understanding that ketones are derivations of lipids, we can learn a lot. For one, just as lipids are composed of free fatty acids and glycerol, we can understand how ketones are a type of acid. Furthermore, we can understand why ketones might not be an immediate, quick energy source since blood glucose is the preferred energy source, and because lipids need to be broken down before the body can and will resort to ketosis. This is also why the keto diet is so relevant to weight loss and efforts to burn excess fat!
Simultaneously, this helps inform why a certain level of ketosis is the prime of burning fat stores at an efficient level. Urine tests and blood ketone tests help identify when you are in nutritional ketosis, having blood ketone levels of 0.5 to 3 millimoles per liter, with the best results occurring between 1 to 3 millimoles per liter.
On the other hand, when ketone levels are between 3 to 8 millimoles per liter, the body has entered the dangerous state of starvation ketosis. This can lead to dehydration, chemical imbalance in the blood, and acidic pH levels, even causing comas or being fatal. Common symptoms include thirstiness or dry mouth, frequent urination, fatigue, dry or flushed skin, nausea, vomiting, difficulty breathing, stomachaches, headaches, and changes to the smell of your breath, typically in a fruity odor.
Since symptoms and reactions to ketosis vary across the board and adjusting to the keto diet may also include withdrawal-like symptoms, it’s often easier to test your blood with OTC (over-the-counter) blood meters and strips to ensure that your ketosis levels are appropriately within range and adjusting your meal times and diet accordingly. As always, be sure to consult your doctor to be sure that a keto diet is right for you since everyone responds differently, and cases are especially different for diabetics or women that may be pregnant or breastfeeding.