Today there was a “discussion” during lunch with coworkers that really frustrated me because I was treated like my opinion and experiences did not matter, and was not allowed to even explain myself before being laughed at and shutdown. Not only was this completely disrespectful, it shuts down the ability to have intelligent discourse on a subject matter, so to allow myself to move on past this, I decided to write my side of the discussion.
The topic in question was nutrition and how to lose weight. I’ve done a large amount of reading on this subject matter. As someone who has struggled with his weight since he was a child, I’m finally at a point where I feel like I know what I need to do to accomplish the things that I want to accomplish and know enough about how the body functions to allow me to make those appropriate actions, even if I ignore them sometimes. To that end, I’ve lost 40 pounds of fat about 5 years ago and have kept it off pretty well. My weight, itself, has fluctuated because I’ve gained muscle, gotten stronger, and just generally lead a healthier life than I ever have in the past.
The topic in particular was the theory that calorie-in/calorie-out (CICO) is the universal “law” that rules weight gain and weight loss, but this concept is a complete oversimplification of a scientific law that is based on, The law of conservation of energy, or the first law of thermodynamics to be more specific.
Quoting Wikipedia (emphasis mine):
The law of conservation of energy can be stated: The energy of an isolated system is constant.
I’m not saying that, ultimately, our bodies do not obey this law, they most certainly do, but what I am saying is that the application of it for weight control is not appropriate and not very useful due to an oversimplification of the law, and a lack of knowledge to be able to perfectly balance energy in vs. energy out.
The first oversimplification is assuming that the human body is an isolated or closed system. While you can use this abstraction to simplify analyzing known systems that are relatively isolated, the human body is too complex, too unknown to be able to really consider it an isolated system or do we have the ability to isolate it in a way that is significant.
The second oversimplification that makes calories-in/calories-out a bad assumption when it comes to weight control is that all of the calorie numbers that you have access to are approximations based on assumptions that add a degree of error (both small and large). Let’s evaluated a number of these approximations that would play into caloric balance and how this, while not proof, makes the likelihood that caloric balance is not the law of weight loss.
The first approximation is basal metabolic rate. This is very difficult to actually calculate given how much we don’t know about energy expenditure in the human body. Average Body Temperature, Heart Rate, outside temperature, how you are feeling, etc all play into how much energy your body spends just on general upkeep.
The second approximation is the calorie count of food. This is based on a sample size, and consistent recipe, composition, size, sourcing of products, quality of the food (in season foods are more nutritionally dense and generally have slightly higher calories than out of season foods), etc.
The third approximation is the number of calories your body expends when you exercise. Each person is completely different, so your treadmill telling you burned 300 calories is a gross approximation and I dare say a completely useless number given the lack of information that those devices have. Things like the bodybug are moderately more accurate because they take things like Galvanic Skin Response into account, but their calculations are completely hidden and proprietary which makes them untrustworthy without unbiased scientific review.
The fourth approximation is the 3500 calories in a pound of fat. If this is what you are basing your weight loss on, you fail to take into account that you will not only be losing fat, but lean mass as well.
Gary Taubes, in Why We Get Fat? points out that, if CICO does rule our weight gain/loss, it would take only an average of 20 calories a day of caloric over-consumption to gain 50 pounds in 20 years. Given all of the approximations above, CICO, to me, seems completely an unlikely explanation of why we get fat.
It’s also well-known that insulin is the trigger of lipid synthesis (moving blood lipids into fat stores), so this seems a more reasonable explanation of the mechanism of “why we get fat”. Unchecked insulin levels, as can be present in insulin-resistant individuals or diets composed primarily of high-glycemic-load foods, one can reason, cause an increase in lipid synthesis beyond the normal range that the body needs to maintain homostasis.
Keep in mind, also, that our fat stores are not static. Fat moves in and out of them constantly, so after we eat, we get a little fatter, and then as we need energy from that food, the fat is released back into our blood stream, so this further indicts insulin as the potential culprit in weight gain. This video from the documentary Fat Head offers a pretty good explanation of how blood lipid and fat cells interact.