What my dog taught me about CI:CO

I’ll get to the bit about my dog in a minute, but first let me tell you about the Calories In : Calories Out theory.  It goes a bit like this;

Calories that you eat – Calories that you burn = Fat that you store

It’s a very simple theory, if you want to decrease your body fat, then eat less, and move more.

It has an interesting corollary.  If you believe this theory then it must follow that;

people who are fat, eat too much, and move too little.

Why does everyone believe this?

Well the first reason is because it is such a simple theory.  We are conditioned to accept oversimplified explanations for complex processes.  Doctors believe it.  Personal trainers believe it.  Even researchers at the  U.S. National Institutes of Health believe it.

The other reason we believe this is a little darker; it turns out that humans kind of like to think of bad things happening to bad people.  Obesity, and the diseases that travel with it like type 2 Diabetes, Hypertension, Cardiovascular disease are a gruesome burden to victims.

It apparently makes us feel slightly better about the world, if we can observe that fat people become Obese as a punishment, for the deadly sins of Gluttony (Eating too much) and Sloth (Not moving enough).

It is simple, but is it also true?

That is the problem.  The theory has never worked – we have tried to help people lose weight by teaching obese people strategies to fool themselves into eating fewer calories (like the past 40 year of fad low-fat diets), or motivating obese people to exercise.  It also does not explain the observation that people who are obese, are also hungry ALL . THE . TIME and yet don’t appear to have the energy to do even moderate exercise.

That hypothesis has never worked because it denies the fact that our bodies operate in an energy homeostasis, that is driven by hormonal signalling that is beneath our notice.  What is more most components of “Calories out” are not in our control, and are coupled to “Calories In”.

Let’s do the math

I’ll give you an example: Let’s say you are using 2000 Calories a day, and eating 2000 Calories a day and then you decided to lose weight by eating only 1800 Calories and doing an extra 200 Calories of exercise … a CI:CO expert will tell you obviously that you will burn off (2000+200)-1800= 400 Calories of body fat.

But what actually happens is you haven’t changed the hormonal signals to alter your rates of energy storage, so your body just sees the shortfall of energy and reduces optional consumption of energy (like heating, or making robust hair follicles, or 1000s of other uses of energy it can chose to turn on or off) and it increases the amount of hunger signals to remind you to increase inputs, and it decreases your perceived energy so you don’t waste any. When you finally stop “dieting” you end up gaining weight rapidly because now you have a depressed metabolic rate that doesn’t recover until your body is no longer threatened by energy availability.

This is the “Yo Yo” dietary experience that just about every dieter has experienced, and even the experts at the National Institute of Health have observed this in contestants on season 8 of “The Biggest Loser” who all gained back the weight they had lost from limiting their caloric input and pushing their caloric output to it’s limit.

After ‘The Biggest Loser,’ Their Bodies Fought to Regain Weight

The Homeostat

I liken the CI:CO model to being in a climate controlled room and you are a bit warm so you open a window, and of course the room then turns up the furnace. Or you are too cold, so you light a fire and the room turns up the A/C. But what you REALLY want to do is just change the thermostat that sets the level of the stasis.

If you want to reduce body fat you need to dial down the “homeostat” that regulates energy storage. That is insulin.

Finally the bit about the dog

So as you may know we have 2 dogs, one of them is a Blue heeler name Bluebelle but everyone just calls her Bloob.  Last year she became an insulin dependant diabetic thanks to a complex chain of endocrine events that started with a tumour on her adrenal gland (which was removed).

The interesting thing about Bloob is that we control her food, we control her exercise, and we also control her insulin.  She has been on a calorie restricted diet ever since she became diabetic.  We feed her the same thing every day, kangaroo mince (fortified for dog food).  She gets exactly 200g twice a day – and we weigh her bowl.


She also has exactly the same exercise every day because we walk her with our geriatric dog twice a day.  I don’t have a picture of her on a walk … but here’s a nice one of her on the beach before she got sick.  It’s not related to the story … but it’s a great photo.


Now here is the interesting thing.  The tumour drove her adrenal gland to make hormones that caused her to produce a LOT of glucose.  We had to give her 50 units of insulin morning and evening just to get her glucose down in the range of 10 mmol/l (dog ranges are the same as humans – so that is really high).  She put on about 10kgs and went from 26kgs to 36kgs, she would spend the entire day just lying in the sun trying to warm up, her metabolism was plummeting.


That photo is a few days after her adrenalectomy where the tumour was removed.  Once that happened her glucose started to drop and we were able to titrate down her insulin from 50 units twice a day to 15 units twice a day.

What happened when her insulin was reduced?

Now remember Bloobs twice daily Food and Exercise remained the same, so Calories In: Calories Out barely changed.


Yup.  She lost all the weight she’d put on while we had her on 100 units of Insulin a day.  She went from having such a big belly that she had to lie sideways in a sprawl in February of 2016, to a dog that could comfortably hold a sphinx position in July of 2016 – just from a reduction in Insulin.

B.b.but the law of thermodynamics

So where did the weight go if she wasn’t eating less, and moving more?  It turns out that she WAS using more energy every day to heat her body, and increasing her alertness and general activity level.   No longer did she have to sit in the sun because she was cold all the time in the middle of summer.  She was comfortably warm in the middle of Winter, and she was chasing butterflies and lizards and other critters (real and imagined) in the backyard all day.

It was Insulin.  Insulin drives whether our bodies store energy or use energy.  When energy is diverted to storage (ie: we’re getting fatter), then we have less energy available to waste (ie: Lethargy), and we seek out more sources of energy (ie: Hunger).

This hormonal theory of obesity also explains the apparent paradox of fat people who are hungry all the time, and never have the energy to do even moderate exercise.

How is that like a ketogenic diet

So you know when we make insulin?   When we eat carbohydrate sources of glucose (sugar and starch), or protein sources of arginine (and to a lesser degree leucine).

A ketogenic diet works because it enables you to produce less insulin.  For those of us who are profoundly insulin resistant, it means we can make the least possible amount of insulin that our bodies have to produce, while still taking in adequate nutrition.  That is why we restrict carbohydrate sources of glucose, limit protein, get all our energy from fat (both on-board and dietary), and let satiation be our fuel gauges.

If you are eating to satiety, you naturally take in fewer calories as you body releases more energy from body fat, under the direction of lower levels of insulin.  You may also find that your exercise level naturally goes up too.  Most people lose weight until they meet the level of their basal insulin at which point they gradually start taking in more calories without even thinking about it and slowly stop losing weight at a new safer lower body weight and it stays off as long as you keep your insulin low.

It’s worth pointing out that reducing insulin can be a significant challenge for those of us with profound Insulin resistance because we can produce 10x the amount of insulin given the same challenge.  This is why for many of us carb-nights, and protein gorging are more problematic than they would be for more insulin sensitive people.  Some of us were just born with a higher minimum setting on our “thermostat” and have less flexibility.  But all of us are entitled to normal blood sugars which the ketogenic diet enables.


The short version is restricting calories is a short term strategy with diminishing returns, the long term strategy is to restrict carbs and limit protein, get your energy from fat and eat when you are hungry and stop once you are not.  If you are type 2 diabetic, this can normalize your blood glucose and save you from suffering all the nasty complications of that disease.

Notable Replies

  1. #loonyketo

  2. I’m surprised we don’t call ourselves Loons.

  3. Great article and explanation! I’m a controls engineer and the t-stat analogy is a very good one. I work with a bunch of other engineers of course, and after I lost 50 lbs on Keto, they wanted to say it was all because I was at a calorie deficit. I tried to explain that its not simply CI:CO and that the body isn’t a closed system, there are far too many variables and things like internal metabolic regulation that vary and a simple CI:CO model cannot illustrate. It is frustrating, because they should know better. They are controls engineers! Feedback, PID loops, process variables, you name it are the norm around my profession. It gets complicated, but even they have been brainwashed by years and decades of bad diet/nutrition advice. I will start using the thermostat analogy if the subject comes up again, and I will see what they say to that… /rant

  4. Richard - First off let me say I fully appreciate the write-up a well as the awesome pictures of your dog.
    I do not argue your statement on the CI:CO model not being correct (mostly in fear of a dog bite), however I fear that this maybe misconstrued by some like myself as a Keto monopoly “Get Out Of Jail Free” card.

    For myself and others that created our obesity situations (or maybe diabetic situations) through large eating based on emotional cue’s - the concept of “eating to satiety” can be thrown out the window given the right (or wrong) emotional conditions as some of us can experience a never-ending hole in out guts, regardless of the amount of fats we eat.
    In addition I have seen Dr. Fung’s reports where cortisol is increased based on stressful factors, and this looks to raise insulin, further advancing weight gain.

    Now, I must note that I have stayed a solid Keto for the last 8 months, and would like to say that my emotional eating has been heavily suppressed, and almost non existent. I have had some emotional/life changes that have helped correct this, as well as certainly a happier mood based that (without a doubt) can be attributed to the way I now eat, as well as the results I have gotten from my diet.
    However, that “addiction” will likely always lurk in me, and does exposes itself in times of happiness now - where a good BBQ or family gathering will push me to eat WAY more protein and fats than I should, and this certainly leads to some temporary weight gain. This gain is lost after a few days of normalized Keto, but if one was to continue this path consecutively, it would without a doubt result in weight gain based on an over consumption of calories to energy expenditure.

Continue the discussion at www.ketogenicforums.com

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