6

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Why do we need to eat fat for Ketosis, if we already have bodily reserves?

Answered on August 19, 2014
Created October 13, 2012 at 11:38 PM

This is perhaps a stupid question, however it's something that's baffled me recently.

If we're burning fat for energy, then why do we need to consume fat if we already have reserves in our body that can be burned, assuming we already do?

Is our body fat a last resort? What then happens to the fat that is consumed and how is hunger then regulated?

Thanks!

D7f404b29047b12e2c2f528934b7b80b

(133)

on October 14, 2012
at 05:59 AM

Not minimal. If i'm not mistaken usually 20% and up. I log my meals with an app and when i'm in ketosis the fat % is sometimes up to 75%

E95023add40ea3d6c77620b82c3d5912

(45)

on October 14, 2012
at 03:48 AM

Thanks! This answer is very straight forward and to the point. Percentage wise, how much fat would you need in your diet then to stay in Ketosis. Would it be very minimal, assuming you were eating the perfect amount of protein to maintain repair?

E95023add40ea3d6c77620b82c3d5912

(45)

on October 14, 2012
at 03:08 AM

In other words, being a smart arse.

E95023add40ea3d6c77620b82c3d5912

(45)

on October 14, 2012
at 03:03 AM

He wasn't suggesting fasting. He said that I should eat absolutely nothing permanently. At least that was my interpretation.

3846a3b61bc9051e4baebdef62e58c52

(18635)

on October 14, 2012
at 01:04 AM

Nope you would totally be in ketosis if you just fasted....so Steve is right on.

64433a05384cd9717c1aa6bf7e98b661

(15236)

on October 14, 2012
at 01:04 AM

While not recommended, studies in the 50s have had obese men fasting for VERY long periods of time

543a65b3004bf5a51974fbdd60d666bb

(4493)

on October 14, 2012
at 12:43 AM

i think its a good question, tho i think the real answer is long & complex. after all, every one gets hungry, even if you are carrying excess body fat around. our bodies do not seem to like releasing "hard earned" body fat stores

2c2349bc7af0fedb59a5fe99dac9fae2

(2707)

on October 14, 2012
at 12:33 AM

I think proponents of eating a high fat diet would say that eating fat keeps your body in a primarily fat burning mode since chances are your insulin levels will be low due to the low carb intake. You have to something other than protein, if it's not carbs, then its fat, which should keep you burning fat. A meal that causes a large insulin spike will cause you to switch to glucose for energy which in turn suppresses fat oxidation.

E95023add40ea3d6c77620b82c3d5912

(45)

on October 14, 2012
at 12:28 AM

Are you being sarcastic, because this is exactly the dilemma I'm facing. I can understand that it would make sense to eat fat if all bodily reserves have been used up, but then it would seem impractical. But I'm just looking for some confirmation or clarification.

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6 Answers

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2
2c2349bc7af0fedb59a5fe99dac9fae2

(2707)

on October 14, 2012
at 12:35 AM

I think proponents of eating a high fat diet would say that eating fat keeps your body in a primarily fat burning mode since chances are your insulin levels will be low due to the low carb intake. You have to eat something other than protein, so if it's not carbs, then its fat.

A meal that causes a large insulin spike (carbs and even protein) will cause you to switch to glucose for energy which in turn suppresses fat oxidation.

best answer

2
77877f762c40637911396daa19b53094

(78467)

on October 14, 2012
at 02:10 AM

Because if you eat carbs you will inhibit ketosis. Also, if you eat lots of protein you may also inhibit ketosis due to gluconeogenesis. Therefore you eat fat because there's very little else to eat that doesn't inhibit ketosis.

The extra fat in the diet wont promote further adipogenesis due to the reduced glycerol availability which will inhibit triglyceride formation.

E95023add40ea3d6c77620b82c3d5912

(45)

on October 14, 2012
at 03:48 AM

Thanks! This answer is very straight forward and to the point. Percentage wise, how much fat would you need in your diet then to stay in Ketosis. Would it be very minimal, assuming you were eating the perfect amount of protein to maintain repair?

D7f404b29047b12e2c2f528934b7b80b

(133)

on October 14, 2012
at 05:59 AM

Not minimal. If i'm not mistaken usually 20% and up. I log my meals with an app and when i'm in ketosis the fat % is sometimes up to 75%

2
00cd3b6f51530a6832fcda1712edbec3

(2411)

on October 14, 2012
at 12:39 AM

The body uses the amount of food you eat as a sensor of the external environment. If you eat too much, your body's hormones will give you signals (usually) to eat less for awhile. If your body thinks you're eating too little, it takes measures to conserve energy. One of those measures is to hang on to your body's energy reserves, i.e., your fat, as tightly as it can for as long as it can. Other conservation measures include slowing your metabolism and making you hungry for your customary foods.

Your body won't release its energy reserves unless (a) you need just a bit more energy than you're eating and (b) you make more of the enzymes required to process the reserve form of energy, i.e., fat. Changing your dietary fuel source from carbs to fat accomplishes (b), among other benefits. Also, since fat and protein are usually more filling for longer than carbs, you're likely to eat less without being obsessed about how much you're eating.

There's a lot of individual variation with this idea, of course. Age, sex, race, ethnicity, thyroid health, hormonal balance, metabolic damage, genetics, epigenetics, birth control meds, exposure to dietary and environmental hormone disruptors and metabolic toxins all influence a person's reaction to eating a fat-based diet.

I was going to link to another discussion on this topic for more reading, but pbo beat me to it.

1
3846a3b61bc9051e4baebdef62e58c52

(18635)

on October 14, 2012
at 01:59 AM

You don't have to eat fat for ketosis at all. You need to not eat carbohydrates. So to get to ketosis you could fast (IF fans like me get into ketosis for several hours each day). You could eat thousands of calories in fat.....epileptic and other disease states that do not want to lose weight, but need to remain in ketosis benefit from this. You could eat sufficient protein and fat to satiety to stay in ketosis as a weight loss and lean mass saving strategy. So really its about your goals.

Hunger regulation happens via several mechanisms including several hormones. In trials protein has shown to have the highest satiety, but fat ....while not as satiating as protein has been shown to slow transit and release hormones that lead to reduced caloric consumption in future meals.

As to body fat its is always being used...at various rates. Fat from meals is easily stored, but also easily accessed when insulin is low.

If you want the actually metabolic mechanisms for any of this order something like this http://www.amazon.com/Metabolism-at-Glance-J-Salway/dp/1405107162/ref=sr_1_1?ie=UTF8&qid=1350180338&sr=8-1&keywords=metabolism+at+a+glance

I actually have this one and its quite useful at time for a reminder.

0
77877f762c40637911396daa19b53094

(78467)

on October 14, 2012
at 01:37 AM

I think, you need to introduce dietary fats to make liver to process fats as a fuel. As far as I know, high concentration of free fatty acids in blood makes liver process them and generate ketone bodies. Using MCT speeds up this process as they (MCT) are readily delivered to the liver via hepatic portal vein.

-1
59fa7cd87fb9d669adf21e5cf3e7ada5

on October 14, 2012
at 12:22 AM

You don't have to eat it, you could just eat nothing at all.

E95023add40ea3d6c77620b82c3d5912

(45)

on October 14, 2012
at 12:28 AM

Are you being sarcastic, because this is exactly the dilemma I'm facing. I can understand that it would make sense to eat fat if all bodily reserves have been used up, but then it would seem impractical. But I'm just looking for some confirmation or clarification.

3846a3b61bc9051e4baebdef62e58c52

(18635)

on October 14, 2012
at 01:04 AM

Nope you would totally be in ketosis if you just fasted....so Steve is right on.

64433a05384cd9717c1aa6bf7e98b661

(15236)

on October 14, 2012
at 01:04 AM

While not recommended, studies in the 50s have had obese men fasting for VERY long periods of time

E95023add40ea3d6c77620b82c3d5912

(45)

on October 14, 2012
at 03:08 AM

In other words, being a smart arse.

E95023add40ea3d6c77620b82c3d5912

(45)

on October 14, 2012
at 03:03 AM

He wasn't suggesting fasting. He said that I should eat absolutely nothing permanently. At least that was my interpretation.

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