Impact of insulin resistance on the CICO law


I used to think weight loss was pretty simple – calories in vs calories out. No matter what you consume, the total number of calories are what make you gain/lose/maintain weight, right? I was recently diagnosed with PCOS and mild insulin resistance. Everybody’s saying that IR makes losing weight incredibly difficult, which is quite a bummer as I’m currently trying to drop several pounds. What I’m wondering is: How does insulin resistance affect the whole CICO rule (the law of conservation of energy, nonetheless!)? It seems sort of unrealistic for IR to make you an exception to the laws of physics. Is it more related to appetite and increased food intake or does it actually alter the way your body uses energy?

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You have it about right. insulin resistance does not violates any basic principles of physics or chemistry. Instead, it just profoundly messes up a great many normal body functions, thus making normal weight loss approaches that much more difficult.

Insulin resistance messes up all kinds of normal functions beyond just promoting inflammation, stimulating growth of body fat, and causing Type II diabetes. It interferes with multiple signaling channels that affect satiety and fat reduction, and it affects the organisms living in the human gut that are critical to proper digestion and metabolic balance.

Biochemist here. I’m not intimately familiar with insulin resistance, but insulin is the signaling molecule your body uses to tell your cells if they should be taking up sugar from the bloodstream, or if they should be using alternate methods of making energy. This is why insulin is so closely tied to blood glucose levels, because it’s essentially telling your cells “its feeding time!”. Type 1 diabetes is characterized by low natural levels of insulin, so even when sugar is available the cells don’t take it up. Also, the same type 1 diabetics don’t respond to low insulin levels by switching over to catabolic energy pathways, and so low blood sugar levels can be very dangerous for them.

This all being said, yes having a disruption to your response pathways to insulin can easily disrupt normal metabolic pathways. It’s not about violating physics; I used to think similarly until I took biochemistry classes. The different energy production pathways in your body all have different relative efficiencies, so the same number of calories can produce different numbers of ATP molecules depending on how they are utilized. To use a poor but adequate analogy, a gallon of gas has a set amount of chemical energy but you’ll get father with a gallon of gas in a Prius than you would with the same gallon of gasoline in a pickup truck

Ultimately, calories in vs calories out is inescapable. If you’re not getting energy from food, and for whatever reason it can’t be released from your various reserves either, you’ll just stop working and die.

Now, this is by no means my expertise, but I don’t think mild insulin resistance should really prevent you from dropping a couple pounds. Insulin is mostly involved in processing glucose that enters the blood, allowing it to be taken up by cells. Other hormones regulate the release of existing reserves like fat and glycogen. In fact, pre-diabetes is often reversible through *weight loss*. The IR might still be messing with normal metabolism and make things more difficult to some degree, though.

How PCOS ties into that is a different story, and not something I know enough about to comment on.

Source: general knowledge of human physiology from MSc in biomedical sciences

These 2 videos both explain very well the effects Insulin, CICO, and fasting(which can fix insulin resistance problems) have on your body. Worth watching and quite entertaining. []( [](

I’ll point out that conservation of energy really isn’t the right way to think of metabolism and weight. We aren’t performing exotic nuclear physics on food. Why we have is conservation of matter: everything we eat has to come out, either undigested or digested and then somehow excreted.

Various metabolic diseases, including PCOS, change both sides of CICO. Your body can absorb more or fewer calories from what you eat, and it can either more readily use those calories to do things (and then excrete the waste products) or try to reduce expenditures.

CICO is always true, but calculating the in and out is not fixed and not trivial!

CICO doesn’t mean what most people think it means…

There are two things that people miss…

The first is that the body is an adaptive system that is driven by hormones, so the body can control the CO part of the equation. It can also attempt to control the CI part of the equation by controlling hunger.

The second is that the body has no “calorie counting” function. Everything is done through hormones.

For people with normal metabolism, if they reduce the amount they eat slightly, the body will sense that there is insufficient energy and it will dip into the person’s fat stores. Though *generally* people with normal metabolism don’t have weight issues as their leptin system works to down-regulate their hunger if their fat mass goes up.

People with insulin resistance have broken metabolism; their livers are producing glucose that is not needed and that means they have elevated insulin *all the time* (otherwise known as hyperinsulinemia). When the body has too much glucose, it tries to burn it off and it does this by reduce the amount of fat metabolized. Normally that’s not an issue, but for people with insulin resistance is happens *all the time*.

If they try to eat fewer calories, the body cannot effectively access stored fat because of the elevated insulin, so the body tries other strategies to fix the issue. It turns down your metabolism, limits your exercise, and tries to get more calories.

In other words, you get cold, tired, and hungry.