I wrote this basic tutorial on ketosis after I received a call from a friend yesterday who told me he was having a debate with a guy on ketosis and it's magic properties. His stance was ketosis is not some magic condition that enhances fat loss independent of cal restriction. He was right the primary ingredient in any weight loss regimen is calorie deficit
How many people can actually define ketosis? Not many that I have spoken with. How can you argue a position if you can't even define what you are talking about?
From Low Carb Dieting the Truth
Before we move any further let me introduce the word ketogenic. Must of you reading this article are probably familiar with the world as it implies low carb or restriction of carb intake. Simply put for our purposes the words ketogenic and low carb are synonymous.
What is a ketogenic diet? A diet that causes ketone bodies to be produced by the liver, and shifts the body’s metabolism away from glucose in favor of fat burning. A ketogenic diet restricts carbohydrates below a certain level (generally 100 per day). The ultimate determinant of whether a diet is ketogenic or not is the presence or absence of carbohydrate. Protein and fat intake vary. Contrary to popular belief eating fat is not what causes ketosis. In the past starvation diets were used often to induce ketosis. I will repeat myself again and say lack of carbohydrate or presence of ultimately determines if the diet is ketogenic.
In most eating plans the body runs on a mixture of protein, fats and carbohydrates. When carbohydrates are severely restricted and glycogen storage (glucose in muscle and liver) is depleted the body begins to utilize other means to provide energy. FFA (free fatty acids) can be used to provide energy, but the brain and nervous system are unable to use FFA’s. Although the brain can use ketone bodies for energy.
Ketone bodies are by products of incomplete FFA breakdown in the liver. Once they begin to accumulate fast and reach a certain level they are released , accumulated in the bloodstream and cause a state called ketosis. As this occurs there is a decrease in glucose production and utilization. There is also less reliance on protein to meet energy requirements by the body. Ketogenic diets are often referred to as protein sparing as they help to spare LBM whiled dropping body fat.
In regards to ketogenic diets there are two primary hormones- insulin, glucagon that need to be considered. Insulin can be described as a storage hormone as it’s job is to take nutrients out of the bloodstream and carry them to target tissues. Insulin carries glucose from the blood to the liver and muscles, and it carries FFA from the blood into adipose tissue (stored fat triglyceride). On the other hand glucagon breaks down glycogen stores (especially in the liver) and releases them into the blood.
When carbs are restricted or removed insulin levels drop while glucagon levels rise. This causes enhanced FFA release from fat cells, and increased FFA burning in the liver. This accelerated burning of FFA in the liver is what leads to ketosis. There are a number of other hormones involved with this process as well.
In general we refer to three different types of ketogenic diets.
1. STANDARD KETOGENIC DIET- A diet containing l00 or less grams of carbohydrates is referred to as STANDARD KETOGENIC DIET
2. TARGETED KETOGENIC DIET- consuming carbohydrates around exercise, to sustain performance without affecting ketosis.
3. CYCLICAL KETOGENIC DIET- alternates periods of ketogenic dieting with periods of high carbohydrate intake
from
Knowledge and Nonsense (Hale 2007):
Ketosis means body fat loss?
This statement is incorrect. Though ketosis represents fat oxidation, the important question is where is the fat comingfrom? If you are consuming high levels of dietary fat (with low dietary carb intake), you can expect increased fat oxidation (primarily coming from dietary fat if you’re in calorie balance or in positive calorie balance). This means that body fat is spared. Ketosis is technically defined as blood levels of ketone bodies reaching 0.2 mmol/dl (even during a mixed diet there are some levels of blood ketone bodies, approximately 0.1 mmol/dl). Commonsense and primary research data tell us there are various nutritional protocols that result in weight loss. Some of the people on the ketosis boards and those who sell low carb foods and supplements may have discovered some new magical scientific data that we haven’t seen yet (ha ha) that says differently.
Technical Note ketone body formation
The primary regulator of ketogenesis in the liver is malonyl-CoA (intermediate in fat synthesis). When liver glycogen is high malonyl-CoA is high. When malonyl-CoA levels drop CPT-1 (transports FFA into mitochondria to be burned) becomes active. This condition increases FFA transport to the mitochondria which increase acetyl-CoA to high concentrations which are condensed into acetoacetic acid, which is further broken down into beta-hydroxybutyrate and acetone the three major ketone bodies.
thanks,
Coach Hale
www.maxcondition.com
ketosis (low carb) tutorial
Linear Mode
