How does Ketosis Blunt Appetite?

[HairOnFire]

Can someone explain the mechanism behind why ketosis acts as an appetite suppressant? What is actually going on that causes the lack of desire to eat? Is it something about fats circulating around, being released?

[Citruskiss]

Not sure if this is precisely what you're looking for, but I found the following:

After a couple of days you will find you are in control of your appetite. That's because once your body's two-day supply of glycogen (stored glucose) diminishes and you make the switch to primarily burning fat, lipolysis suppresses your appetite. - Dr. Robert Atkins, in "Dr. Atkins New Diet Revolution" p. 139

and..

in the section on Pre-Maintenance, on page 199:

But be careful! There are a couple of reasons why peopls sometimes get into trouble:

1. They don't recognize that this phase is still relatively restrictive of carbohydrates, compared to the way they were eating before they were doing Atkins.

2. They're startled to discover that without the wonderful advantage of deep lipolysis, appetite suppression has diminished. ~ Dr. Robert Atkins in "Dr. Atkins New Diet Revolution" on page 199

[dane]

From Lyle McDonald's "The Ketogenic Diet: A Complete Guide for the Dieter and Practitioner":

Several studies have compared appetite on a very low calorie (below 800 calories/day) ketogenic diet versus appetite on a balanced diet with the same calories (14,15). In general, no difference was seen in appetite between the two diets. This leads researchers to think that ketones do not blunt appetite in and of themselves. Rather two possible mechanisms seem a more likely explanation for the appetite blunting seen with a ketogenic diet.

First, is the relatively higher fat content of the ketogenic diet compared to other diets. Fat tends to slow digestion, meaning that food stays in the stomach longer, providing a sense of fullness. The same has been shown to for protein (14). Additionally, protein stimulates the release of the hormone cholecystokinin (CCK) which is thought to help regulate appetite.

However, studies using very-low-calorie intake (and hence low dietary fat intakes) have documented this same blunting of appetite, suggesting a different mechanism. Rather than the effects of dietary fat, the researchers argue that what is perceived as a blunting of appetite is simply a return to baseline hunger levels. That is, during the initial stages of a diet, there is an increase in appetite, which is followed by a decrease over time. It is this decrease which is being interpreted by dieter’s as a blunting of appetite (14,15).

Overall, the data supporting an appetite suppressing effect of ketogenic diets points to a mechanism other than ketones. This is not to say that appetite may not be suppressed on a ketogenic diet, only that it is most likely not ketones or metabolic ketosis which are the cause of the suppression.

Anecdotally, some individuals have a strong suppression of appetite while others do not. This discrepancy can probably be ascribed to individual differences. If a dieter’s appetite is suppressed substantially on a ketogenic diet, it may be difficult for them to consume the necessary calories. In this case, the use of calorically dense foods such as mayonnaise and vegetable oils can be used to increase caloric intake. If appetite is not suppressed on a ketogenic diet, less calorically dense foods can be consumed.

[mike_d]

Critics claim its due to toxins created by eating too much protein which makes your blood turn acidic. I find the effect, whatever its due to, lessens over time-- I hardly notice it now, but I am not always hungry like I was on HC.

[HairOnFire]

Critics claim its due to toxins created by eating too much protein which makes your blood turn acidic. I find the effect, whatever its due to, lessens over time-- I hardly notice it now, but I am not always hungry like I was on HC.

Do you buy this claim? :)

BTW, I feel the same as you - the blunting effect has decreased considerably but I also don't get the wild hunger pangs I used to have on high carb. I'm doing IF, so I can go long periods without eating and be fine.

I liked the Lyle McDonald quotes, but every time I've seen studies cited by him, they appear to be outdated, and I wonder if these are recent, or if it matters in this area of research?

[pennink]

Ketosis should NOT be confused with ketoacidosis... this from Wikipedia (not my usual source, but it's clear) describes the difference.

"Ketoacidosis is a type of metabolic acidosis which is caused by high concentrations of ketone bodies, formed by the deamination of amino acids, and the breakdown of fatty acids. This is most common in untreated type 1 diabetes mellitus, when the liver breaks down fat and proteins in response to a perceived need for respiratory substrate. It can also occur with people undergoing hunger strikes, fasting over 3 days, or people starving to death as the body is forced to break down fat for sustenance due to their lack of outside nutrition.

Ketoacidosis should not be confused with ketosis, which is one of the body's normal processes for the metabolism of body fat. In ketoacidosis, the accumulation of keto acids is so severe that the pH of the blood is substantially decreased."

[HairOnFire]

Pennink, you just answered another question I've had about acidity of the blood. Thanks! :agree:

Do you have any opinions on how ketosis affects appetite? :wave:

[pennink]

Pennink, you just answered another question I've had about acidity of the blood. Thanks! :agree:

Do you have any opinions on how ketosis affects appetite? :wave:


I like to read Dr Eades about all this... try here, and search around to find out anything you might like to know.

http://www.proteinpower.com/drmike/?p=761

[AceofCarbs]

i'm fairly new to ketosis... can someone help explain what it is?

[HairOnFire]

i'm fairly new to ketosis... can someone help explain what it is?

It's when you use up your glycogen stores and start running on body fat. Ketones are the byproduct of fat utilization.

Like pennink, I recommend the Eades blog she linked to. You will learn tons there! :agree:

[pennink]

i'm fairly new to ketosis... can someone help explain what it is?

Your brain needs glycogen ('sugar') so your body when it sees there isn't anything from your food, starts looking around for a source. It finds your fat. It turns your fat into ketones and your body burns its own fuel and you lose the fat. Dr Eades also explains that your heart for one and other organs actually run better on ketones. A heart 'runs' 28% better than on sugar.

I love his analogy to cavemen... go read, it's "food for thought" :lol: