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Let's say based on my level of activity I "burn" 3500 calories worth of energy each day.

Let's say I only eat 1750 calories of low-carb paleo chow.

Does that mean I'm "burning" 1/2 pound of body fat to make up the difference?

Now consider what would happen if I ate 1750 calories of high carb chow: I would not be in ketosis. I would have elevated insulin levels (a storage hormone).

Would my high carb food choices prevent me from burning stored body fat, even though I only ate about half my energy requirements?

From reading the Taubes book, I have the impression that the first priority be to sweep the 1750 of carbs into my fat cells? What happens next confuses me: if I still had energy demands (above and beyond what I ate), would I be burning stored body fat, despite the elevated insulin?

Or, would my metabolism slow down so my new daily energy needs is about 1750 calories?

Any thoughts would be appreciated.

Thanks, Mike

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You lose 1/2 a pound of fat either way. (+/- a little glycogen/protein). Firstly, if you are eating fewer carbs than you are burning, you're glycogen would be replenished first prior to any carbs being stored as fat. Secondly, fat is ALWAYS being released by adipocytes - even in the presence of insulin. Don't be misled by a theoretical discussion of what's happenning in the fat cell. It's what's being burned in cells/mitochondria all over the body that really counts. And (as much as I hate to admit it) Carbsane is usually correct. The Taubes theory sounds good, but is probably incorrect. – Dave S. Apr 13 2012 at 14:13
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However, low carb IS useful for two reasons. Protein reduces hunger (many studies show this effect). Low carb is usually higher protein and therefore blunts hunger. Low carb diets can be ketogenic. Ketogenic diets also reduce hunger in study after study. It is also theorized that low carb diets have less 'food reward' value and therefore do not stimulate overeating and are thus helpful in weight loss. While it may be possible that insulin (or the lack of insulin on a low carb diet) plays into some of these effects, such as reduced hunger, the "locking fat away" idea has little merit. – Dave S. Apr 13 2012 at 14:20
The answer to your question is yes. Assuming you are relatively normal and healthy. I'm not sure the same rules apply for a type 2 diabetic. – Dave S. Apr 13 2012 at 14:23

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You're on the right track. The short answer is: insulin moves energy into fat; lack of insulin allows energy to move out of fat.

In a healthy individual, this isn't a problem, like kenckar says, between meals, your insulin will come down and you'll burn that fat you stored. What Taubes is most concerned with is in the metabolically deranged / insulin resistant person. In these people their insulin is chronically elevated so basically they never get that energy back out of their fat cells and just keep putting on weight. That's also why someone who's insulin resistant can be ravenously hungry and feel like they're starving even if they have the fat; they can't use it, so their brain is panicking and telling them to eat more.

This is why Taubes has come to the conclusion that insulin is the one hormone to rule them all (for fat loss). If you can control the insulin, you can control your available energy. That's a hot topic on PH, so I'm not going to argue either way.

On to your example, If you need 3500 cals to be as active as you are and you ate 1750 as low carb: you're right, you'd just pull the extra out of your fat for the day, losing about 1/2 a pound.

But if you ate 1750 of carbs, some of gets used for fuel right away, the other part gets shunted to your fat cells because your insulin goes up. What happens next is the question. If you're a healthy individual, your insulin will come back down and you'll pull what you need out of fat and essentially lose another 1/2 pound or so. If you're insulin resistant, then you're out of luck. You can't pull that energy out, so now you get crazy hungry. If you don't ever get around to eating, then your body has no other choice but to slow its metabolism because there's no energy around to use. This is where Taubes says "you're not fat because you're lazy, you're lazy because you're fat". I.e., you just can't move because the energy isn't available for you to use.

You'll also notice something in that example above with the insulin resistant person:

  • They need 3500 calories
  • They eat 1750 calories
  • They use (say) 875 calories immediately from blood sugar; the other 875 gets stored because insulin was/went up

That means, they took in what they thought was 1/2 of their caloric need, hoping to lose 1/2 of a pound, but they ended up storing 1/4 of a pound worth of energy and only getting 1/4 of their need for the day actually used. That's the kind of thing you see when insulin resistant people try to diet (by cutting calories but keeping the carbs up). In this case, they effectively only got 1/4 of their daily need for energy from their food, they gained some weight, and they had to slow (sometimes irreversibly) their metabolism down. I think that's why the food quality matters more than food quantity when losing weight (of course, you do have to know the difference between your mouth and vacuum cleaner).

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Unfortunately, there's no evidence that supports this scenario. – Evelyn aka CarbSane Apr 13 2012 at 12:27
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Uh, no evidence? Go read (and I mean read, no skim) Good Calories, Bad Calories. Taubes spends about 1000 pages showing evidence of this. – miked Apr 13 2012 at 13:36
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Oh please don't tell Evelyn to read Taubes! I much prefer her focused on Dr. Kruse. @Evelyn, ever tried looking at Ray Peat's stuff? (There's at least 6 month's worth of blogging right there.) – Dave S. Apr 13 2012 at 13:57
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I gave a simplistic view on insulin because it was all that was needed to illustrate the answer to the original question. There's no need to go into all the details here. Sometimes, to be clear you have to be simple and then hit the details later. Taubes covers all of the details of insulin in GCBC, I'm not going to rewrite 1000 pages here to answer a simple question. I understand that insulin is a signalling hormone to get sugar in lots of different cells, not just fat cells. But it still doesn't change the fact that you can't get energy OUT of fat when insulin is around. – miked Apr 13 2012 at 14:44
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Again...simple physical picture...KGH does a great job of explaining dynamic equilibrium (I have a chemical kinetics background, so I understand this very well), and how it applies to insulin and fat. But I simplified the story so that I could describe the big picture. If you want every answer on PH to be a 15,000 word essay covering all possible nuances, then PH will become as useless to the average person as reading a scientific journal. We have to become more lenient with levels of abstraction that cover the topic at hand. – miked Apr 13 2012 at 15:57
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In between meals your insulin would go down and you could release the fat. Also, your metabolism would drop, but probably not so much that 1750 would be maintenance.

Even if you had a slow steady 24 hour drip of carbs going into your system, presumably your insulin would not raise so much beause you would be in a continual caloric deficit with the calories going to fuel your body.

You have to think through what happens through the cycles, not simply taking a day as a unit.

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Before you go buying into Taubes' theories, consider this. There's nothing like exercise to lower insulin levels, yet Taubes is adamant that exercise is useless for weight loss because it will only make you hungry.

I've not read WWGF in its entirety, but I'm aware that it contains a scenario whereby insulin makes you hungry and causes overeating (oh I know, that's inane!) starting on p. 122 (Google books). You think about carbs, secrete insulin, eat carbs, secrete more insulin that locks the fat away making you hungrier so you eat more and more. Yet insulin lowering exercise makes you hungry.

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If you are eating a low-calorie high-carb diet, you will be in deficit and your will eventually burn some body fat, although probably not as much as if you consumed the same amount of calories from a lower carb diet. Your insulin levels won't be as high if your calories are restricted.

The real question though is whether this is a sustainable approach in the long-term! Many studies have shown that a calorie-restricted diet rich in carbs (and therefore low in fat) is not satiating at all compared to a lower-carb higher-fat diet.

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Unless you are eating ultra-high levels of protein, fat will not be the only thing you are burning. That much of a deficit over more than a few days will put you into a muscle consuming state which consumes your muscles for the necessary amino acids your body requires. So looking at such a deficit as only fat-burning will ignore the effect of muscle loss, regardless of the effect of insulin. Personally, I think if you were that active and your metabolism was not deranged, none of those 1750 calories would be stored, since they would be used for your body's energy needs.

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miked linked this skeleton from the cave. It was interesting so I'll add my N=1 response.

The answer to your question is YES.

I was insulin resistant (A1C=8 fasting) and had no trouble losing 2-3 lbs/week for 3 months in this condition. I did not run % body fat, but the loss of visceral fat was obvious in my waistline, and in my thinning round face and thighs. I ate carbs during this period, but less in both dietary % and absolute level than I did before I started losing weight. Certainly nowhere near VLC level - at least 150 grams per day.

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