In my previous posts, we saw how easily the blame got shifted to us for being gluttons and sloths; how  we have been led to believe “ a calorie is a calorie”,  it doesn’t matter whether it comes from a broccoli or candy; how they tried to convince us about the laws of thermodynamics which basically translates to the CICO ( Calories in vs Calories out) hypothesis ( Fat = Calories in – Calories out).

I mentioned how it was almost impossible to measure our daily energy expenditure or the ‘calories-out’ part of the equation, considering the various metabolic and physiological functions that goes on all the time in our body, over which we have no conscious control. We also saw that exercise or conscious movement to expend energy is only 10% of the daily energy which the body expends. Yet we are always told to ‘eat less and move more’ in order to lose weight!! Eating less?? Well, maybe it works……

In this post we will discuss a few studies to test the CICO hypothesis in reality.

This sick-o (CICO) hypothesis tells us 2 things:

  1. balance your calorie intake with your calorie expenditure ;
  2. the energy we consume and the energy we expend have little influence on each other. That we can consciously change one (eat less) and it will have no consequence on the other (expend energy), and vice versa.

Almost a 100 years ago, the first study on effects of calorie intake reduction Entitled “A Biometric Study of Basal Metabolism in Man”, was done in 1917-18 at the Carnegie Institution of Washington’s Nutrition Laboratory on 12 healthy young men. They were put onto ‘semi-starvation’ diets consisting of 1400-2100 calories per day and then observed with measurements of energy expenditure taken. Their energy expenditure dropped substantially – a whopping 30%. The men complained constantly of being unable to stay warm, even with an “abundance of clothes”. Heart rate and blood pressure dropped. Men showed a marked inability to concentrate and marked weakness during physical activity. In other words, their metabolism was shutting down.

Let’s think about what is happening here. Let’s assume these people normally eat 3000 calories per day. Since they are neither gaining nor losing fat, they are burning 3000 calories per day. Now we restrict calories to 2000 calories per day. With roughly a 1/3 reduction in calories the body responds by reducing caloric expenditures (shutting down).

Calories are needed to heat the body. So, the body turns down the body heat. Result – the patients feel cold, no matter how much they try to put on clothes.

Calories are needed to pump the heart. So, the body slows that down. Result – heart rate decreases.

Calories are needed to maintain blood pressure. So, the body turns that down. Result – blood pressure decreases.

Calories are needed to think (brain is very metabolically active). So, the body turns that down. Result – inability to concentrate.

Calories are needed to move. So, the body turns that down. Result – weakness during physical activity.

In other words – the body more or less imposes an ‘across the board’ reduction in caloric expenditure.

Why does the body do this? Well, because the body is smart and doesn’t want you to die. Consider a person normally eating 3000 calories a day. Now, he eats 2000 calories a day. If he were to continue to expend 3000 calories daily, he would soon burn all his fat store, then his protein stores and then he would die. Nice. Why would he want to do that? The smart thing to do is to immediately reduce caloric expenditure to 2000 cal/day to restore balance. Why do we assume Mother Nature is so damned stupid?

Any rational person would adjust to the new 2000 calorie a day diet by reducing energy expenditure to not just 2000 calories but a little less (just in case), say 1900 calories. This is exactly what the body does. Because it is the SMART thing to do.

In the study, what happened to their weight under strict calorie restriction? The men did initially lose weight, but what happened next is probably familiar to all those who have tried to diet. After the experiment ended, they regained all of that weight and even a little bit more. The total energy expenditure- TEE- (or Calories Out) dropped so substantially that returning to a normal diet meant that the men started to regain the weight. When they lost the weight, they lost muscle and fat. When they regained the weight, it was all fat.

Moving forward several decades, the noted scientist Ancel Keys, sought to study the effects of caloric reduction in the famous Minnesota Starvation Experiment, published in 1950.

Ancel Keys estimated that these subjects were eating roughly 3,200 calories per day. They were put onto a ‘semi-starvation’ diet of 1,560 calories per day with foods similar to those available in war-torn Europe at the time – potatoes, turnips, bread, and macaroni. They were then monitored for a further 20 weeks after the semi-starvation period.

What happened to them?

Coldness, incessant hunger, weakness, exhaustion, dizziness, muscle wasting, and hair loss were some of the symptoms.

Heart volume shrank by 20%. Heart rate slowed. Body temperature dropped.

The total energy expenditure – TEE- dropped by 40%. Interestingly, this is not that far off of the previous study from 1917 that showed base energy expenditure decreased by 30%. In other words, the body was shutting down. Let’s think about this again from the body’s point of view. The body is accustomed to getting 3,200 calories per day and now it gets 1,560. In order to preserve itself, it implements across the board reductions in energy.

The heart gets less energy – heart rate slows and heart volume shrinks. Blood pressure drops.

The heating system is turned down – body feels cold.

Muscles get less energy – physical exhaustion.

Hair and nails get less energy – hair loss and brittle nails.

Not to mention the psychological effectsObsessive thoughts of food. Bingeing behavior. Extreme depression. Severe emotional distress. Irritability. Loss of libido. Interest in everything other than food vanished. Social withdrawal and isolation. Anyway, I’m sure you are beginning to get the picture.

The key to remember, though, is that this ensures survival of the individual under a time of extreme stress. Yeah, you might feel lousy, but you’ll live to tell the tale. This is the smart thing for the body to do. It is not so stupid as to keep burning energy it does not have.

Consider the alternative. The body is used to 3,200 calories per day and now get 1,560. The body still burns 3,200 calories. Things feel normal. Three months later, you are dead. It is absolutely inconceivable that the body does not react to caloric reduction by reducing caloric expenditure.

What happened to their weight after the semi-starvation period?

In the 24 weeks of the starvation period both body weight and body fat dropped. As they started upon the recovery period, they regained the weight. Actually, the weight was regained rather quickly – in about 12 or so weeks of recovery period, the weight is back to original. However, it does not stop there. The body weight continues to increase until it is actually higher than it was before the experiment started.

And body fat! It goes soaring above baseline. The dirty little secret of most dietary studies is that as weight is lost, both fat and muscle weight are decreased. But when weight is regained, most of it is fat.

eat-less-exercise-moreThink about it in dietary terms. Let’s review what happens when you go on a calorie restricted diet of 1,560 calories/day – just like your doctor tells you to do. You feel lousy, tired, cold, hungry, irritable and depressed. That’s not just because you are dieting, there are physiologic reasons why you feel so crappy. Metabolic rate drops, hormones make you hungry, body temperature drops and there are a multitude of psychological effects.  Our weight may reduce initially, but then the body would respond by reducing TEE to about 1,560 cal/day. Even after 1 year, things are exactly the same. We feel lousy and the weight is not coming off despite our best efforts to eat only 1,560 cal/day. If you have ever been on a diet – you probably know how that feels.

Discouragement sets in. We get tired of feeling so lousy so we go back to our regular diet. All the weight comes racing back with a little extra for good measure because now we are eating 3,200 calories/day and expending only 1,560. Sound familiar? Consider the last time you tried to diet by reducing calories and portion size. Does any of this sound familiar? Yeah, thought so.

But in truth, the failing was not ours. The portion control diet, the essence of the CICO hypothesis, is virtually guaranteed to fail. It has been proven over and over in the last 100 years. The only reason we think that it works is because everybody – the doctors, the dieticians, the ‘scientists’, the media – has convinced us that it is all about ‘Calories in vs. Calories Out’. Eat less -Move more and that kind of idiocy.


When you follow the advice that all the “experts” repeat over and over, in every source you see and hear, and you don’t see the expected results, it’s logical to assume you are not following the advice hard enough, or well enough, right? It’s logical to assume you are to blame, rather than stopping to question whether there might be something wrong with all that “expert advice.”

It is increasingly clear that one of the key assumptions of the CICO hypothesis, that the energy we consume and the energy we expend have little influence on each other, is incorrect.

The caloric expenditures and caloric intake are inextricably linked to each other.

We saw how our metabolism was shutting down when we reduced calorie intake, but what happens when we increase our portion sizes!

Let’s now fast forward to the modern era, and look at this study published in the prestigious New England Journal of Medicine. 

The question they wanted to answer was what happened to energy expenditure (TEE) when weight was increased or decreased. Would the body automatically compensate by increasing or decreasing energy expenditure? In other words, if we reduce or increase our Calories In, what happens to Calories Out?

In this experiment, 18 obese and 23 non-obese subjects with a stable weight were recruited. They were fed a liquid diet of 45% carbohydrate, 40% fat and 15% protein until the desired weight gain was achieved.

Well, what happened?

In response to increased portion sizes, instead of a simple calories in, calories out model where fat is deposited according to an excessive intake of calories, it appears that the body responds to excess calories by trying to burn it off! In other words, an increase in Calories In causes an increase in Calories Out.

Let’s put this into a dietary context. Suppose we increase our portions keeping our diet composition constant. Weight may increase but the body’s response would be to increase TEE – body temperature may increase, energy and sense of well being may increase. We may eat 2,500 cal/day but the body has now increased TDEE to 2,500 cal/day. No further weight will be gained and the body will attempt to reduce our weight back to the original. In the meantime, we feel great.

Rather than the simple balancing scale of calories in=calories out, it appears that our body acts much more like a thermostat. That is, the body seems to have a certain Body Set Weight (BSW). Any attempts to increase above this BSW will result in our body trying to return the body to its original weight by increasing TEE (increasing metabolism to burn off the excess calories).

Any attempts to decrease below this BSW will result in our body trying to return the body to its original weight by decreasing TEE (decreasing metabolism to regain lost calories). No wonder it is so hard to keep the weight off!

Something changes the BSW, something causes the thermostat to malfunction. We see that so often as we age. What regulates our BSW? Can we re-program our BSW to our lean mid-twenties setting?  Understanding that is the key to end our unhappy relationship with food.

Our bodies are very finely tuned with respect to what they store.  What you eat matters a lot, but much less because of the actual caloric content of the food.  The reason what you eat matters is because of the hormonal impact food exerts over your body.


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