Just How Does KETOSIS Work?

[hesselite]

I've heard a few different stories. After hearing about the Atkins diet from my brother, I always understood ketosis as reducing the amount of sugars/carbohydrates to next to nothing causing ketones to be produced. These ketones, in turn would then begin to break down fatty acids (in the form of triglycerides) as a source of energy. If you eat more fats, you will go into ketosis faster and begin to break these down. Net result: your body begins to rely on fats (triglycerides) as a source of energy.

My physiology prof, who incidently wrote the textbook we are using explained the production of ketones as a result of low blood sugar levels. The ketones do not actually facilitate in the breakdown of fatty acids. In fact, they are simply the RESULT of the breaking down of triglycerides into fatty acids and glycerol.

If this is true, then it only makes sense that when you begin to consume sugars/carbs (glucose) your body stops relying on fats for energy, and the ketones are then converted back into Acetyl-CoA, and your body begins to rely on glucose as a source of energy.

He also said, that if you wanted to burn more fats, if you were to somehow rid yourself of ketones in your system, your body would incidently want to produce more (to achieve a balance) so you would begin to break down fats to produce more ketones. Get rid of those, you break down MORE fats to produce ketones to replace those... get rid of those.... etc.

Is this the truth about ketosis? Do ketones actually do anything?

I think this would make an interesting research project... finding out how to remove ketones from the body and if this hypothesis is in fact correct.

Any input would be appreciated.

--Hess

 

[Burning_Inside]

do some searches on google.com about lyle mcdonald and ketogenic diet and bodyopus.

 

[Kid Dynamite]

Ketones are partially broken down fatty acids. Your body will rely on them as energy when you have no glucose in your system for 2 or 3 days, and adaption takes up to 8 days in some people.
Ketones are excreted through the urine, so if you wanna try your experiment, drink a ton of water every day while in ketosis and see how your fatloss is.

 

[AMBB4L]

Ketosis is just too complicated to explain in one reply -- Read Duchaine's "Body Opus", or follow the advice given by Burning Inside

 

[PwB]

Ketosis is when whole body energy utilization goes away from using glucose as a primary energy source and instead towards using free fatty acids and ketones as an energy source. To achieve ketosis, one does not nead to eat next to no carbs, technically, anything under 100g of carbohydrate a day is ketogenic, causing blood ketone levels (ketonemia) to increase. (BTW, ketones are ALWAYS present to some degree, just much less than when in ketosis)

The idea that as one eats more fat they get into ketosis faster is a long believed myth but completely false. Ketosis develops just as readily on a low fat, low carb diet as it does on a high fat/low carb diet. Its not the presence of fat that causes ketosis but the absence of carbs/sugar (as well as keeping protein reasonable, as too much may prevent ketosis from excess converting into glucose via gluconeogenesis). Many believe this since it was written in the outdated bodyopus, and b/c they show deeper ketosis (purple) when testing ketosis on ketostix. Understand ketostix are useless for dieters and only show ketonuria (ketones excreted from the urine), not ketonemia (ketones in the blood) which is what counts. As one adapts to ketosis, less ketonuria b/c the body excretes less ketones and instead becomes more efficient at using them for fuel (mainly for the brain since free fatty acids cant be used since they can't cross the blood brain barrier)

Your professor is correct as ketones cause no fat loss but are the result of it, when ffa are partially broken down in the liver, ketones are produced.

There is some lag time between ingesting carbs and still using ffa/ketones for fuel, and one may eat carbs for several hours and will still be burning ketones and fats for energy.

Your professors philosophy is flawed and he doesnt seem to undertand the adaptions that are taking place over several weeks in ketosis. It seems he is saying you rely of fats and ketones during ketosis. Get rid of ketones and you need to use more fat as energy b/c ketones are present. Well, understand that only during the 1st 3 weeks of a ketogenic diet, ketones are being used by most tissue of the body. By the 3rd week almost all ketones are being used to fuel the brain (75% of energy for the brain can be fueled by ketones), the rest of the body is relying mostly on free fatty acids as an energy source. So to burn more fat, cut calories or exercise more. It would NOT be desirable to remove ketones b/c w/out glucose, the brain relies on ketones as its primary energy source and there is even evidence it PREFERS ketones. If you want to get rid of them the only option is eat carbs/sugar but this defeats the purpose of the diet. So once adapted to ketosis, the body IS relying mostly on free fatty acids (up to 90% of energy is being provided from fat at rest and low intensity activity), since most tissue by the 3rd week uses the ffa and only the brain uses the ketones.

 

[PwB]

Just to clear things up, the brain normally requires 100g glucose a day on a "balanced" diet. When in ketosis 75% of its energy can be provided from ketones since it can't use ffa since they cannot cross the BBB (blood brain barrier). The remaining 25% energy can be met from a small amt. of carbs eaten each day or conversion of amino acids (mainly glutamine and alanine) into glucose via gluconeogenesis. So w/out glucose to fuel the brain, and no ketones if they could be somehow removed, then the brain has no fuel source. No fuel source for the brain, and I would theorize death would soon follow. If you look at the adaptions that occur over time in ketosis, the main one is to fuel the brain during ketosis. No ketones, no brain fuel. So if you don't "feed your head", you'll be dead. LOL

 

[Kid Dynamite]

Adding something to PwB's last post, brain adaption to ketones can take up to 8 days for some people. That's why you'll generally feel shitty for the first few days.