Keto diets have become a popular diet trend not only because they have the potential to target fat cells when done properly, but allows for one to eat a higher fat diet. This is because the "keto" diet focuses on shifting your bodies primary energy source from glucose, the monomer of carbohydrates, to using ketones which are derived from fat. We have a great article that breaks down cellular respiration and explains why glucose is used as the bodies primary energy source which you can access here, but for this article we're going to be focusing on the use of fats to fuel the body in the keto diet and how this is achieved. The keto diet is not the best for those looking to improve strength and build muscle as it is a very low carb diet which affects vital glycogen levels, however it is highly beneficial for those looking to lose fat in the most efficient manner. Below we'll go over the idea behind it, what it achieves, and expected results!
Where the "Keto" Comes From
Our bodies typically use glucose as it's energy source however that is not the only option it has, just the preferred one. However, when your body shifts to using fats for energy, it produces what are known as ketone bodies as the byproducts. These ketone bodies are produced in the liver, where your body metabolizes the fat, and then the ketones are then circulated for your other organs such as your brain and muscles to use as energy. The breakdown of fat and production of ketone bodies occurs when:
- There is not sufficient amounts of bioavailable glucose circulating and your glycogen levels are depleted. Glycogen is the storage form of glucose that is stored in your muscle cells and liver as an energy reserve. When these levels are low resulting from a lack of replenishment from a low carb diet, along with low blood sugar and insulin levels, the body looks for another energy source; which next up is fat
- The above symptoms typically occur when a person has undergone prolonged aerobic exercise, has been fasting, or is engaging in a low-carb (ketogenic) diet
- This leads the body to begin to breakdown fat for energy as it is pushed into what is known as ketosis; this involves a process known as beta-oxidation which allows the ketone bodies produced to generate energy for your celss
- When people are following a ketogenic diet they are purposely pushing their bodies into ketosis to burn existing fat as a result from an extremely low-carb diet (typically between 20-50 grams of carbs a day).
Types of Ketones Your Body Uses and The Process
In order for your body to use fats as energy a specific process involving ketone bodies and beta-oxidation must occur.
When blood glucose and insulin levels are low from a lack of carbs, resulting in elevated glucagon levels (hormone that triggers release of glucose or fatty acids into the blood) fatty-acids are released from adipose tissue(as glucose levels are depleted from the keto diet) or are metabolized directly from your food source in the liver to produce ketone bodies as a result from the breakdown of fatty acids. There are three ketone bodies that your body synthesizes, acetoacetate is the first as it is the direct product of the breakdown of fatty acids:
Acetoacetate results from the direct breakdown of fatty acids causing this molecule to be a derivative of two acetyl-CoA molecules that have lost their CoA (cozyme A) molecules. This allows the two molecules left to form a covalently bonded dimer with two ketone groups ( double bonded oxygen pictured above). This molecule is responsible for transporting energy from the liver to other organs, along with the next ketone body; Beta-Hydroxybutyric-Acid.
2. Beta-Hydroxybutyric Acid (BHB)
Beta-Hydroxybutyric acid is also responsible for transporting energy to other cells from the site of ketone body production in the liver. Unlike Acetoacetate, it is not form directly from the breakdown of fatty acids, however it is formed from the reduction of Acetoacetate (the negatively charged atom on the acetoacetate molecule gains an electron in the form of a hydrogen to form a hydroxy group (OH)). It is important to note that the entire structure of Beta-Hydroxybutyric Acid is not a ketone as it does contain only a single-bonded oxygen as a result from the reduction reaction it undergoes from acetoacetate, but it still contains 1 ketone group and functions as a ketone body.
Both of these above mentioned ketone bodies are energy transporters due to their ability to be converted into Acetyl-CoA by every cell in the body with the exception of the liver. The conversion of these molecules into Acetyl-CoA allows the cells to undergo cellular respiration starting at the citric-acid cycle (TCA) in the mitochondria. The aceytl group is oxidized during TCA to produce ATP and the byproducts needed to enter the Final step of the cellular respiration and the most energy efficient one; the Electron Transport Chain. If you don't know what cellular respiration is or want more info check out our article here!
Acetone is the third ketone body that is produced spontaneously as a byproduct of the enzymatic breakdown of Acetoacetate. This ketone body is pretty unstable and is typically removed either in urine or through breath quickly after formation. It is the decarboxylated version of acetoacetate so it is not an energy transporter as it cannot be turned into acetyl-CoA directly to be used in cellular respiration. It must first be converted into lactic acid by detoxification in the liver, where it can be oxidized into pyruvic acid, and then acetyl-CoA. Since this is an extensive process, your body typically rids of acetone and relies on Acetoacetate and BHB to produce the Acetyl-CoA to generate energy for the body.
The Keto Diet; Requirements and Food Sources
Now that we have the background info on ketone bodies and where and how they're formed, we can address the actual diet. The goal of this diet is to eat a one high in fats, while being extremely low in carbohydrates and moderately low in protein. However, what must be understood is that in order for the diet to be effective in burning fat you currently have, you must still eat fewer calories then you are burning to drop the fat. While you are pushing your body to burn fat as energy, if you are consuming too much fat you're body will use the ingested fat sources to produce energy and not tap into your "reserves", aka your fat tissue. In order to understand the recommended portions of macros you should be ingesting, we recommended using our Total Daily Energy Expenditure (TDEE) under our macro calculator! In order to figure out your daily totals:
- Answer the 4 simple questions to find out your TDEE.
- Go To Keto Calculator Below and Enter Your TDEE and Whether You Want To Lose Fat or Maintain
- Receive grams of each macro you need to be in Ketosis
(Please type in answers, copy and pasting your tdee number won't work correctly in some browsers)
Once you have calculated your breakdown of Fats, Proteins, and Carbs you can plan your daily meals by fitting that macro breakdown by portioning your food to meat the nutrition facts on all the food you eat!
If You Need Help Finding Food To Reach Your Daily Goals, Check Out Some of our favorite Keto Foods Below or Contact Us:
- Low Carb Vegetables: Brussel Sprouts, Broccoli, Cauliflower
- Red Meats/Lean Meats (lean meats are lower in fat and higher in protein)