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-   -   Carb depletion can shut down the body's ability to burn fat? (http://forum.lowcarber.org/showthread.php?t=459291)

Molly B Wed, Apr-02-14 11:13

Carb depletion can shut down the body's ability to burn fat?
 
A website I am looking at suggest that you CAN eat carbs before exercising and still lose weight. But I am confused. What does this mean--- it says that "if you are constantly carb depleted due to 0 calories of glucose intake, you can shut down your body's natural fat burning capabilities."


I know I can't/shouldn't believe everything I read, esp online, but I want to hear what you guys say about this. Here is an excerpt from the page:


****************
So if you are on a low carbohydrate diet, I highly recommend carbohydrate intake for exercise sessions that are 1) intense; 2) involve weight training; 3) are longer than 2 hours in duration.

Although many folks use this as an excuse to eat more carbs than they should there is certainly truth to the fact that “fat burns in the flame of carbohydrate” – meaning if you are constantly carb depleted due to zero calories of glucose intake, you can shut down your body’s natural fat burning capabilities.

So if you’re planning on exercising, try get at least 500-600 calories of carbohydrate per day, and eat them before, during or after your exercise session if you want them to not affect your blood sugars levels in a potentially damaging way.
***************************

What does that mean, that carb depletion can stop our ability to burn fat? I am confused! I cut out most carbs, limiting them to about 30 a day (net carbs), and I have lost weight. Does the statement have something to do more with glucose? (But don't simple carbs turn into glucose?)

PS--I'm not trying to find a good excuse to eat simple carbs, I'm just confused about how/why the statement says carb depletion can shut down our body's ability to burn fat.

Here's the link to the page, if anyone wants to read it. It is called '10 ways to do a LC diet the right way." http://www.bengreenfieldfitness.com...-the-right-way/

ojoj Wed, Apr-02-14 11:29

I've not heard that before - well I've heard of people "carbing up" prior to exercise, but not that without carbs our bodies cant burn fat - thats just plain wrong - Mine did!

Jo xx

Seejay Wed, Apr-02-14 11:48

Carb depletion stopping the burning of fat? Well maybe sort of sometimes. Your author might be assuming everyone's a sugar burner. which many high volume fitness people are.

Imagine a person who has been a sugar-burner. If they go suddenly VLC, there's no sugar any more, and their body is not set up yet to burn fat. it needs different enzymes and mitochondria and what not. They aren't burning much of anything. This is the famous adaptation period.

Even a VLC person gets glucose from the extra protein so they're never zero glucose as this writer talks about. He might be assuming people are NOT adding extra protein for exercise, or that people aren't VLC or something. Notice he's talking about the ability to exercise intensely and long. Both of those require glucose.

A good source for understanding carb, fat for exercise is Mark Sisson

Why Fat, Not Sugar, is the Preferred Fuel

What Does It Mean to Be Fat-Adapted

Elizellen Wed, Apr-02-14 12:04

I did intense exercise for several years while on my weightloss journey without needing to "carb up".

I just had to make sure I kept drinking water.

Nancy LC Wed, Apr-02-14 12:38

You know, if you go around looking for all the anti-LC stuff spouted over the years--most of which are either wrong or totally made up--you'll spend all your time posting them here.

Why not take some time to read some good books and get all those questions answered ahead of time. Then when you encounter BS like this you'll recognize it for what it is.

ojoj Wed, Apr-02-14 13:23

Quote:
Originally Posted by Nancy LC
You know, if you go around looking for all the anti-LC stuff spouted over the years--most of which are either wrong or totally made up--you'll spend all your time posting them here.

Why not take some time to read some good books and get all those questions answered ahead of time. Then when you encounter BS like this you'll recognize it for what it is.



...... or just try it and see!

Jo xxx

Molly B Wed, Apr-02-14 13:36

I've read Wheat Belly, that was great! And I wasn't looking for anti-LC stuff; in fact, I was looking for proof that high fat IS what is required for a LC diet.... because my mom doesn't understand why I am adding back in butter and heavy cream, and other high fat foods.

And so when I came across that author's page, it really had me confused. I thought maybe I had missed something...

Thanks for the help!

ojoj Wed, Apr-02-14 13:43

Quote:
Originally Posted by Molly B
I've read Wheat Belly, that was great! And I wasn't looking for anti-LC stuff; in fact, I was looking for proof that high fat IS what is required for a LC diet.... because my mom doesn't understand why I am adding back in butter and heavy cream, and other high fat foods.

And so when I came across that author's page, it really had me confused. I thought maybe I had missed something...

Thanks for the help!



It is difficult I know! So much conflicting information. In the end, you have to try things and decide for yourself. When I started atkins 11 years ago, I thought it was nonsense it was known that "fat makes us fat" How could this silly diet work??? But I thought I'd try it for a couple of weeks - well, nothing else had worked and I was just getting fatter, why not............ Now, I'm cross that I didnt try it sooner lol!!!! Even now tho, I still get people who think I'll get fat cos I eat so much fat and I must be unhealthy..... I should stop....duh!

Jo xxx

M Levac Wed, Apr-02-14 14:37

It's the other way around. Carb intake can disrupt our ability to first release fat from fat cells, and then to metabolize that fat into ketones at the liver, and finally to metabolize those ketones in every other cell for energy. It works this way. Insulin regulates fat tissue such that when it rises, it inhibits the release of fat. Then, insulin regulates liver metabolism such that when it rises, it inhibits ketogenesis. Finally, insulin regulates glucose/ketone metabolism in every cell such that when it rises, it shifts metabolism toward glucose and away from ketones in an either/or fashion, but that point is moot as there's fewer ketones already from the lower ketogenesis at the liver and from the lower release of fat at the fat tissue. Actually, when insulin rises, all other cells will shift toward glycogenesis - the storage of glucose through conversion into glycogen, since insulin inhibits glycogenolysis - the breakdown of glycogen into glucose, and this occurs primarily in the liver as well, which is how the liver regulates blood glucose.

Additionally, if we use my paradigm (you can read it on my blog), ketones directly regulate insulin through insulin receptors at the liver, since the liver is the primary site of insulin degradation. And this in turn allows insulin to drop and then to continue to provide the substrate - fat - for the ongoing ketogenesis at the liver. It's a brilliant system.

Bear in mind this is just my opinion, not necessarily how it actually works. But again in my opinion, it's the best hypothesis I could come up with so far.

DeannaK Wed, Apr-02-14 14:47

Wow...MLevac...that's awesome.

MollyB...Wheat Belly was good but try also Gary Taubes, "Why We Get Fat.."...outstanding for me and really drove home all the horrors we do to our bodies. We were not meant to process all the crap we feed ourselves.

Eating this way to live a healthy, happy, inflammation-free life works for me and whole host of others.

Like Nancy and others said, best to try for yourself. Eating fat does not make you fat...in fact, it probably makes your bodily systems work better than ever!

Deanna

Molly B Wed, Apr-02-14 15:00

Yes, MLevac, that WAS awesome! I spent a good amount of time this morning trying to find just that info you posted! I should have waited for your post instead, haha! My head was swimming...

I have Taubes' other book in my cart at amazon--just waiting for a paypal payment first so I can then check out. I had forgotten he wrote more than 1 book-- and I want to get all of them! I do so much better if I have books I can read and use for reference. Sometimes all of this info online makes me so confused, esp when a lot of it is opposite of what I thought was correct. How many times today did I read that a LC diet is dangerous? TOO many times! I've lost almost 50lbs by eating LC. My spine pain is so much better, and so is my BP and blood work! How can that be dangerous?!!!! PLUS-- I get to buy new clothes, SMALLER clothes!!! Now tell me how that is dangerous!! :-D

M Levac Wed, Apr-02-14 15:09

Here's some anecdotal data that might clear things up about glucose. Steve Cooksey - that Diabetes Warrior guy - did an experiment with a continuous BG meter during bouts of exercise. As we can see, BG rises on its own during exercise. So if we believe we need glucose for exercise, we don't actually need dietary glucose, the liver gives us all the glucose we actually need, and does it without all the problems associated with the rise of insulin that accompanies dietary glucose.

http://www.diabetes-warrior.net/201...d-diabetes-cgm/

To summarize, we don't need dietary glucose, but more than that, and if we do eat glucose, it disrupts our ability to burn fat.

M Levac Wed, Apr-02-14 15:24

Personally, when I went all-meat, I was still going to the gym and lifting heavy weights. Didn't affect my ability none. In fact, I retained my strength and could lift just as heavy as I did when I weighed 220lbs at my peak (300lbs deadlift was my max at the time). More than that, I even increased the intensity of my workouts, i.e. HITT, more intense drills, quicker motion with same weight, etc.

teaser Wed, Apr-02-14 16:30

I've been working out for almost thirty years, and low carb for almost ten. I didn't notice any real difference, in the long run, with or without carbs.

Ben Greenfield is a triathlete, and that's skewed his perception some. If a person is keto-adapted they might be less prone to bonking--but there are limits to what the human body was meant to be put through on a regular basis. He ran into thyroid problems (pun unintended), so now he buys into the theory that a certain minimal amount of carbohydrate is necessary to maintain proper thyroid function. Maybe that's what he's talking about.

During total starvation, a human being will manage to burn a fair amount of fat--but total oxidation of glucose will only be somewhere around twenty to thirty grams. If fat burns in the fire of carbohydrate, it sure doesn't take much.

In that state, almost half the glucose that's oxidized is replaced by synthesis from glycerol that's released during lipolysis.

He's right about more glucose being used during weightlifting type activities, but not necessarily about this having anything to do with needing to eat carbohydrate. Lifting weights doesn't completely oxidize glucose--it breaks it down to pyruvate and lactate, this releases energy faster than you can get it from fat. Pyruvate can feed into the mitochondria as Acetyl-CoA, and that's an irreversible step--glucose carbon is lost to the body. But if you're fat/keto-adapted, your body will have lots of Acetyl-CoA available from breaking down fat, so production of Acetyl-CoA from pyruvate is greatly downregulated--so a more likely fate of the pyruvate or lactate is that it will be used in the process of gluconeogenesis to replace the glucose that was broken down. During starvation, hundreds of grams of glucose are normally broken down to pyruvate--this is how red blood cells get all their energy, they have no mitochondria--but only that twenty to thirty grams or so of glucose is permanently lost to the system.

I've pushed this thing so far as doing my usual workouts while doing a fat fast. Long term, I'm sure the low protein would hurt--but short term, my workouts got better, not worse. Although I put that under the do-not-try-this-at-home category. :lol:


There are mouse studies where a ketogenic diet of 95 percent fat and 5 percent protein calories resulted in mice with a higher percent body fat. When researchers tried putting a running wheel in their cages, suddenly the diet wasn't fattening anymore. The ketogenic diet didn't make them fat unless it was paired with a particularly unstimulating environment that kept the mice from being their naturally active selves. If you've ever seen a rodent in a cage or in a field, the difference in activity is pretty obvious.

Point is--these mice managed to burn fat with no carbs, and with so little protein that they didn't dare make much of it into carbs. More evidence that "fat burns in the flame of carbohydrate" might be true to a certain extent--but we really aren't talking much carbohydrate here.

rgrandy Fri, Apr-04-14 07:59

Good post
 
I like TEASERS blurb
Quote:
Ben Greenfield is a triathlete, and that's skewed his perception some. If a person is keto-adapted they might be less prone to bonking--but there are limits to what the human body was meant to be put through on a regular basis


I couldn't imagine being and endurance athlete and being ultra low carb. Maybe he found that being ultra low carb and trying to compete really limited performance? IDK.. Seems like most people that go low carb are for weight issues. I haven't seen any professional triathletes that are having weight issues. Most of them tinker with diets for the sake of maximizing performance.


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