Hi all,

I'm writing an article about weight loss for a national Canadian magazine and have been reading about carb sensitivity. I'll be interviewing a few obesity experts for the piece, but in the meantime, can anyone help me understand how the following process [quoted from a blurb about a book] might work? "People with carb sensitivity can't lose weight just by restricting calories, because eating carbs leads to an insulin spike, which opens up fat cells."

My question is: If you're eating fewer calories than your body requires to sustain itself, how can you not lose weight? Insulin spike or no spike, isn't the body FORCED to dip into its fat stores to release energy? Or am I misunderstanding the whole carb sensitivity thing?

TIA Freelance

I am trying to do some research to be able to help you out. From what I see, carb sensitive individuals have a spike in blood glucose after consuming carbs, this in turn causes them to release more insulin than a non carb sensitive person. Insulin is a transporter that allows things into the cell, such as glucose, potassium, etc. It has lots of roles in carb and lipid metabolism. More insulin would cause the larger amount of glucose in the blood access into the cells. Additionally, Insulin inhibits breakdown of fats in adipose tissue and promotes synthesis of fats in the liver. This would cause the person to have a very difficult time burning off any stored fat while consuming carbs. Their energy usage would come from the glucose and they would store fat. Insulin Article NIH Insulin Article

Aside from that argument, I also found an article that discussed the other adverse affect of carb (or insulin) sensitivity. This article does say that with alternating amounts of sugar intake the subjects maintained their weight - not gained, but they don't explain if they altered the caloric intake or not. Article

I hope this helped in some way...

This is what I know, from my experiment/research of one (me!).

Actually, in an NPR segment, I heard that the IR (or carb sensitivity) is actually not a maladaptation, but rather a survival mechanism that humans have developed, so that lower calories would not equal losing weight (in the past, that would have lead to death, rather than thinness).

So, no, it is not a perfect math equation.

The body's ability to turn excess calories, in particular carbs, into fat storage is what makes the "carb sensitivity" possible. This helped humans in the past not die of starvation (low caloric intake) because the fat stores were there to keep them alive.

Obviously, nowadays, it's a problem, rather than an advantage!

To convert fat into usable energy is difficult. It's easier to use the existing energy in your blood (glucose) or protein (i.e. muscle).

If you control the insulin levels in your blood, you control how much of it is put into "fat" storage.

What does this mean for calories? Well, if you starve yourself enough -- my endo recommended at MOST 1200 for my weight loss -- you can lose weight. But it also has to be low-carb. Otherwise, my body will take all those carb calories and convert them into fat. Someone else might take those calories and simply store them as glucose in their muscles or whatever else.

My body is structured to survive famine. Yay!

But, also -- and it might not be for your article -- the carb sensitivity isn't something that can be taken out of the context of other metabolic processes that our bodies goes through. This is just one piece of the puzzle.

The pancreas (insulin) also has other functions that affect your hunger levels and all of that is controlled by your overall body in terms of metabolism -- for example, studies have shown that PCOS women have lower metabolisms than "regular" women, even adjusted for weight/eating patterns. That means that as a PCOS woman, my metabolism will be lower, which means I have to eat lower calories. (Again, saving me from famine, gotta love my body!)

With that, you have to take into account as well the effects of your environment -- endocrine disruptors in our environment can affect all these systems and how they interact with our appetite (satiety cues in our brains and bellies), the speed of our metabolism, and how our bodies convert food (energy) or spend it (the spending part is important too).

Because of my hormone wackiness, I can develop muscle pretty quickly -- I won't look like a body builder, though! -- but I also become very efficient in my workouts. So, I start burning less calories even in an intense workout. So, I have to increase the level of intensity or change it.

Sorry, going off on a tangent now.

I hope that helps!

This is largely what Gary Taubes speaks about in his books. I would recommend looking him up, as he has a slew of references cited in his works.

I am not gifted with the ability to accurately quote studies from memory, but he has some very interesting references in his book "Why We Get Fat".

Thanks for your detailed explanation, Rana. The above was especially helpful.

F.

I agree that Gary Taubes book is one of the better resources for understanding Insulin Resistance. I'd suggest reading both Good Calories, Bad Calories - and Why We Get Fat (I haven't read the latter, but I understand it's much less technical). If yo're going to write an article on Insulin Resistance in any way, I'd recommend reading at the barest of minimum these two books. Though you might also consider reading books written specifically on insulin resistance and also on diseases linked to insulin resistance such as autoimmune disease, and other books on low-carb eating (which Taubes explains very well, as to why low-carb eating is one of the best tools against insulin resistance).


What you're misunderstanding is that you're assuming that the IR person is eating fewer calories than their body requires to sustain itself, and you're assuming (falsely) that their bodies are burning the same number of calories than an average person (often they're not).

If you don't allow an IR person to eat anything, they will eventually starve to death (losing weight in the process) just like everyone else - it will just take them much longer to do it (in a famine, I have the natural advantage - but sincde the odds of famine are pretty low in the USA, it's not much of an advanatage).


IR folks have difficulty losing for two main reasons (and the degree to which a person experiences one or both probably depends on a lot of factors).


1. they're eating more calories than they need to sustain their body's function, but it's much less than a normal body needs to function - and in fact the less they eat, the more their bodies misfunctions. They're metabolism can shut down to the point that they have to eat ridiculously little to lose (often despite being hungry all of the time).

The IR body is like a big company that's having cash flow problems. When "funds are low" the company starts "cutting the funding" to nonessential processes (unfortunately in the body, one of the first departments to be cut is the immune system).

And the second reason that IR folks have difficulty losing weight

2. Insulin is a hormone, and it's one of the growth hormones, and before other hunger hormones were discovered it was often called "the hunger hormone." The insulin spikes don't just trigger hunger, they can trigger intense hunger that can be extremely difficult to ignore.

I always wondered how I could feel not just hungry, but "starving" when my stomach was full to the point of pain. One of the answers is insulin. Insulin hunger can be so bad that for years (before I knew it was from insulin), I would refer to it as "rabid hunger."

I suspect I was IR most if not all of my life. When I tried Atkins as a teen (at around 225 lbs) , I actually passed out twice and almost passed out on several occasions. From the time I was a small child, I couldn't eat sweet foods for breakfast because I'd get incredibly sick about 40 minutes after.

I recognize both these symptoms now as a result of insulin-triggered hypoglycemia. The insulin spike causes a blood sugar crash that causes these symptoms.

In my own case, I believe that for most of my life I couldn't lose primarily because of reason #2. I don't think I burned fewer calories than non-IR folks, but I ate a lot more TONS more, but not because I was lazy or greedy but because of the insulin hunger.

However, reason #1 has become a much larger factor. The calories that it now takes to maintain my weight (all 290 lbs - and all 394 lbs of it when I was that size) is a calorie level that earlier in life would net me 5 - 8 lbs loss each and every week for months (I'm not just talking the first week of a weight loss program here).

As I said earlier, when the body begins "cutting funding" immunity is one of the first to go. I have immune system problems (my immune system is wonky in several ways - reduced immunity, hypervigilant immunity, and autoimmunity). My body temperature is also much lower than normal on a high-carb diet.

A low-carb diet can reduce insulin resistance (or reduce the impacts of insulin resistance). For me, it's been an absolute godsend (rabid hunger has virtually disappeared).

I can explain that quote very simply - it is not true.

The simple fact is that regardless of insulin sensativity a person on a caloric deficit will lose fat. Plenty of studies have been done on this and even older obese women who are strongly "carb sensative" lose weight on a high carb diet. To boot when these are ward studies meaning the people are on 24/7 lock down the weight difference between different diets is very similar. When they are not a ward study the low carb diet with similar groups has an advantage and I believe there are two major reasons.

1) Insulin sensativity can affect the output side of the energy equation which means that an insulin resistant person will likely be lethargic after consuming carbs and which will reduce NEAT and SPA.

2) Compliance can be affected heavily by macronutrient composition. In otherwords a low carb, high protein diet might be easier for an insulin sensative person to follow. (Self reporting food intake makes it easy to cheat)

As always, John can explain in few words what takes me pages and pages to accomplish. Yeah! John

I think it's also important to realize that there are far more than 2 reasons why it's difficult for insulin resistant folks to lose weight, but many of them boil down to hunger, fatigue, and metabolism (and metabolism incorporating all of the ways in which the body "spends" calories).

One thing I've noticed since I've been on a lower carb diet, my body temperature is higher (suggesting my metabolism is "burning hotter") and my hair is growing again.

For a long while I was losing a lot of hair around my crown, and all my body hair (head and elsewhere) had virtually stopped growing (I had NO hair on my lower legs for over two years - now I'm having to shave regularly again).

It's amazing to me how much the body can do to conserve energy.

Whether it's all related to insulin resistance or not, I can't tell you.

Thanks for your detailed and (as usual) logical explanations, Kaplods. Re: the above, I have the opposite problem: an ability to ingest large quantities of sweets at any time of day without feeling any ill-effects. It's what has gotten me into trouble, weight-wise. When I was four, I ate a whole box of chocolates in one sitting. My dad apparently told my mom, "Good, she'll get sick and go off chocolates." Never happened. I've been known to eat a 400g jar of Nutella for breakfast -- that's 2,000 calories of sugar and fat. I never felt sick or lethargic afterwards. On the contrary, I had more energy than usual! So I've had to learn to moderate these tendencies.

F.

p.s. I actually know quite a bit about insulin resistance, having written a lot about diabetes. What I didn't know, until you informed me, was how insulin resistance can affect caloric needs.