Thursday, January 20, 2011

Is it all just Calories In Calories Out?

So I had a debate the other week with some friends about whether or not Calories In - Calories Out works to explain weight gain/loss. I, in general, agree with Gary Taubes in that saying that you eat more and excercise less when you gain weight is stating the obvious but also does not necessarily show a cause-effect relationship (ie. do you eat more and therefore gain weight or is your body in weight gain mode and therefore you are compelled to eat more?).

Lately we hear every day about the twinkie guy who lost weight on a diet of twinkies. Now, for now I will ignore the possibility that his diet was a moderate carb diet and just say, so what? This proves that one guy can lose weight at a calories intake of 1800 calories. It says nothing about an advantage to different macronutrients ratios, it says nothing other than that this one guy did something and got a result.

So anyway, I had the brilliant (?) idea this morning to tackle the calories in calories out debate in a blog this morning because I'm getting so tired of the sanctimonious slim people telling the fat people 'just eat less and exercise you stupid slothful glutton'. To me this is like someone born to a wealthy family telling a poor person to just make more money and spend less. As a much slimmer person who used to be a fat person (300 pounds down to 210 and planning on losing some more), let me tell you, if fat people could get slim and more importantly stay slim simply by concentrating only on eating less and exercising more, they would do it. The ridicule and scorn overweight people face on a daily basis can be intense. The source of that scorn and ridicule is both internal and external. Going into a clothing shop and having staff come up to you with the 'Can I help you' but the look in their face saying 'there's nothing that'll fit you here' is enough to make anyone want to eat less and exercise if that were all it took.

So here's what I'd like to do. I'd like to look at Calories In/Calories Out and show some of the complexity of the equation. To start, the idea of CICO comes from the first law of thermodynamics which states:

Energy in a system = Energy put into the system - Energy removed from the system.

Pretty basic. Energy cannot be destroyed.

How does this apply to a human body? Well it means:

Calories stored  = Calories Eaten - Calories Burned - Calories Excreted.

That last bit I added because frankly you can't tell me our waste products are devoid of energy. Otherwise, insects and bacteria that feed off of them would not be able to otherwise. We can debate about the effect of excretion but it should be included. I'd also like to expand the Calories Burned to make the equation:

Calories Stored (CS) = Calories Eaten (CE) - Calories Burned through Conscious Movement (CBCM)  - Calories Burned through normal base metabolic processes(CBMP) - Calories Excreted (CX)

I think this is a relatively complete formula.  It seems simple but when you look at it a little deeper you see how each component is not independent of the other, and how other external factors besides just weakness of character can play into things.

Psychology - Is it possible that people eat too much and exercise too little because they are lazy gluttons? Yes, I suppose it is. But what other psychological factors can contribute?
  • Depression can be a powerful motivator that paralyzes people. I can say from experience, when depressed, getting myself to exercise takes a herculean effort that is successful sometimes but unless the depression alleviates is difficult to maintain with a level of consistency.
  • Sugar (and probably refined carbohydrates, rice, potatos, etc.) affects the reward centers of the brain in a similar way as some recreational drugs. This can create a bona fide addiction. Given that CW tells us that these things are healthy because they are low fat, the addiction is reinforced by the message we receive from the mainstream.
  • Any emotion can be a trigger for people to eat. We eat because we are happy and celebrating, we eat because we are sad and commisserating, we eat because we are bored or stressed. I don't know for a fact but I suspect some but not all of this emotional eating may be precipitated from the addiction mechanism I mentioned above, and also by the blood sugar fluctuations resulting from a high carb diet.

Calories Stored - How can the calories stored affect the other components of the equation?
  • Well, we know that leptin is the hormone sent out by our fat stores to receptors in the brain to signal when to stop eating. So, that is one way in which the calories stored can affect the calories eaten.
  • Also, if leptin levels are chronically high as they are in obese people, these receptors can get resistant to the signal so the cutoff signal can get lost and an obese person can remain hungry long past when they have eaten enough.
  • Calories Stored (either as fat or muscle) also affect the calories burned through normal metabolic processes. The body has to burn more calories to maintain body mass. the difference between fat and muscle burning is small (five pounds of muscle burns 24 calories a day more than five pounds of fat) so it's not much of a difference in the form of mass. This is also important as we lose weight.
Quality of the calories eaten - While CW says a calorie is a calorie is a calorie, the effect of those calories on the body can be significantly different.
  • Protein when ingested is first used to rebuild cells, then it is converted to glucose and can be burned or stored as fat. This process of conversion takes calories making it inefficient.
  • Carbs (especially refined carbs and sugar) when ingested cause blood sugar to rise first. They are then burned first (before stored fat) and if the body cannot burn it off fast enough, it stores it as fat. More on this in the next section on insulin.
  • Fat, this is converted to fatty acids in the system and either burned if there isn't enough glucose in the system to supply the bodies needs, or stored, if there is enough insulin to store it all.
  • It is possible that the quality of what we eat affects the number of calories that are wasted through excretion. When fat is converted to glucose for the body to use, there is a by product created called ketones which can also be used for fuel. If there are more ketones in the system then are needed, these get excreted. It is also possible that increasing fibre intake may cause more calories to be wasted through excretion. I've seen some discussion about the idea that why a low carb diet works as well or better than a calorie restricted diet even when more calories are eaten is a result of a greater proportion of calories being excreted.
Insulin - Insulin affects a few parts of the equation.
  • Calories Stored - Insulin is the storage mechanism for blood sugar to fat (amongst other things). Chronically high insulin levels (caused by insulin resistance) can cause a disproportionate amount of calories to be stored as fat than normal leaving less calories available to burn. It also prevents the fatty acids from leaving the fat cells since higher insulin levels are a signal to the body that there is excess glucose in the system that must be burned first before fat.
  • Calories Eaten - Since high insulin levels cause a disproportionate number of calories to be stored and prevents the release of energy, it is possible that the body will feel a deficit in the number of calories available to burn and the number of calories needed by the body to support it's energy needs. As a result, the person will feel the discomfort of hunger driving them to eat more, even if they have enough fuel in their fat stores to service their needs.
  • Calories Burned through Conscious Movement - If the person does not eat more as a result of insulin preventing energy from being available to burn, the body may respond by feeling lethargic.
  • Calories Burned through Metabolic Processes - If the calories available to burn drops too low, the body can respond by slowing down it's metabolic processes. One study I read a review of (in Gary Taubes book) showed the body of obese rats pumped full of insulin shut down organs before giving up any significant amount of it's fat stores.
  • Calories Eaten - I am mentioning this again because there is another way insulin affects the calories eaten, and that is by suppressing leptin receptors. Chronically high insulin can make a body leptin resistant as well as insulin resistant. This means the receptors are unable to read the signal from the fat stores that enough calories have been stored and eating should stop.
Calories burned through conscious movement - The exercise we do can also affect other components of the equation:
  • Calories Stored - If the body is functioning well, exercise can cause pull fat out of storage to be used to burn in exercise. Of course if insulin levels or high, this release of fat stores is suppressed.
  • Calories Eaten - Exercise can also make us hungry, this increasing the drive to eat more.
  • Calories burned through normal metabolic process - Exercising (especially resistance training) causes muscles to break down and be rebuilt. This causes the background metabolism to increase the number of calories burnt to make these repairs.
  • Overtraining can also cause the body to shut down, cause a person to become depressed, and cause a person to want to give up and have a milk shake.
What am I missing here? Well I know there is probably alot. I didn't mention the media with it's re-inforcing of the low fat, calories in calories out, exercise until you drop mentality coupled with the constant displays of processed packaged convenience food and the myriad of real fad diets (lemon juice and cayenne detox, the grapefruit diet, etc). There are probably a billion metabolic processes that I missed as well.

All this to say, telling people to eat less and exercise and calling them lazy gluttons is doing us no good. While the first law of thermodynamics holds, it tells us nothing about the interplay of the different components of the real equation within the body. If all we had to do was eat less and exercise to lose weight, we probably wouldn't have an obesity epidemic. However if we realize what affects the behaviors of eating more or less, of having the energy to burn and wanting to burn it, of optimizing how we eat (not just how much) so the body is more predisposed to burning calories than storing them, we would be on a far more successful path on getting past the obesity epidemic.

1 comment:

  1. Really great synopsis, Mike. I can't comment on the physiological details of the processes you've described, but I really appreciate the extra levels of analysis that you're uncovering here for this discussion. Really worthwhile post, thank you.