Why Calories In – Calories Out does not work as advertised
It is basic physics is what they tell you – the First Law of Thermodynamics, which basically states that energy equilibrium is always preserved. If your body uses a certain number of calories in a day (the Calories Out side of the equation) those either need to come from an equal amount of ingested calories, or stored calories (the Calories In side). Drop “Calories In” by dieting, increase “Calories Out” by exercising and you lose stored calories (fat) to maintain balance.
As anyone who has ever tried this knows, it does not work exactly as advertised. The basic reason for this is that this is a absolute equation when applied to a static system – however, our body is a robustly dynamic system with a multitude of variables which constantly change in an adaptive response to our environment. I posted previously on the concept in this post on BMR – Basal Metabolic Rate
Precision Nutrition – Can eating too little actually damage your metabolism?
Exploring the truths and fallacies of ‘metabolic damage’.
Brian St. Pierre, a Registered Dietician, author, and contributor at precisionnutrition.com, has posted an article recently titled “Can eating too little actually damage your metabolism? Exploring the truths and fallacies of ‘metabolic damage'”. It is a very thorough and in-depth article which considers why we have a harder time losing weight after previous dieting, or in the later stages of a current diet. I am linking to the article at the bottom of this post and highly recommend reading it for a good understanding of the challenges you face in weight management.
Brian goes through the Energy Balance Equation (calories in -calories out) in great detail and identifies the various factors which make it very difficult to actually know both the energy in side of the equation as well as the energy out side. Between six interrelated factors which influence each other in both synergistic and antagonistic ways, it is no wonder the equation does not work as advertised.
I am truly in awe of the human body and the complexity of the various metabolic systems which make it up. It seems the best we can do is try to live in harmony with its requirements as much as possible, gauge our results periodically, and be willing to adjust as needed to adapt to what our body’s current needs are. Please take some time to read the article in full, it will give you a better appreciation of the strategies you will need to consider as you work towards your own ideal wellness.
Here is the link to the PN article: