There has been a lot of debate about the accuracy, usefulness and relevance of calorie counting recently. This is in thanks due to the emergence of the Carbohydrate-Insulin Model which offers an alternative energy balance model to the current Mathematical-Calorie one—and it does so by applying a human physiology lens (rather than a physics lens) to the physiological disorder of weight gain.
Yet, the Calories in – Calories out dogma continues to dominate our diet and medical weight loss culture. Among weight loss clinicians, many continue to apply this equation when treating excess weight as they find it represents the fundamental principle of energy balance. At the end of the day, weight gain can only be explained by a positive-energy balance, right?
“Well, if calorie counting worked, it would have worked by now”
…and by “worked”, I mean worked in achieving long-term weight-loss success. Not short-term success. I think we can all agree that we are interested in a discussion about long-term successful dietary strategies. Otherwise, these are called gimmicks.
Anyone who has ever calorie counted will all agree one thing: it works (in the beginning). If calorie counting really worked, however, it should lead to consistent, long-term success.
However, does a deficit of 3500 kcal truly measure out to one pound of weight loss on the scale? Consistently? It likely stopped working weeks later despite following the same calorie deficit. To lose more weight, did you have to become more restrictive with this so-called fundamental “energy currency”?
When calorie counting doesn’t work for others, then why don’t we believe them? Is it because they can’t count? Or is it because they’re too lazy to continue calorie counting? It’s because calorie counting doesn’t work and all explanations to rationalize why calorie counting hasn’t worked for others is just another form of weight bias. If calorie counting worked, it would have worked by now.
“Calories” is not an energy currency our brain or body understands
Let’s go back to high school Biology. Now where exactly in the human cell or within the Kreb’s Cycle do calories get computed again? That’s right—nowhere. Calories is an energy currency for the physical sciences—not the biological sciences. The energy currency humans specifically use is called Adenosine 5′-triphosphate, or ATP. We just don’t have a way to measure ATP practically for energy balance purposes, but even if we could…
Thermodynamic laws of energy conservation can only be applied to closed physical systems, not open biological systems that are driven by genetics and hormones.
Current models to understand obesity in medicine and diet culture continue to look for causes of positive energy balance (i.e. why someone consumes more energy than they spend). Somehow this got extrapolated to a belief that any other explanation not based on energy concepts would be in direct violation of the First Law of Thermodynamics (i.e. law of conservation of energy).
What is the first law of thermodynamics? It’s the law stating that energy cannot be created or destroyed—only transferred.
However, this energy paradigm is based on basic physics reasoning mistakes. For all my fellow Kinesiology nerds, this review is a beautiful read on the topic. I will summarize it nevertheless:
For starters, the First Law of Thermodynamics is an equation, not a formula (ΔE = Calories in – Calories out). While equations and formulas have an “=” sign, they mean different things. Formulas must be calculated; equations must be solved. We continue to apply this equation as a formula to explain why weight gain and now obesity happens. This creates the wrong perception that Calories in – Calories out can be computed on its own and be disconnected from the physiological behavior of ΔE. We incorrectly assume that Calories in – Calories out is not dependent on the changes that may happen within ΔE—such as the direct effects of individual physiological, hormonal and genetic processes.
The other consequence of misapplying this equation as a formula is that it perpetuates the idea that our adipose tissue (i.e. fat stores) is a lifeless mass that just accumulates energy from the residue of excess caloric intake. However, we know that adipose tissue is a very active and hormonal organ—not a simple storage center. What is currently regarded as cause may be just an effect of the changing lipophilic behavior of fat tissue.
The failure of this energy paradigm to fix the obesity epidemic should be enough to lead all of us to question the validity of the whole calorie counting paradigm for weight loss. Need another reason to question calorie counting? Look no further that the history of calorie counting for weight-loss itself…
I challenge everyone to investigate the history of calorie counting
The calorie began its life as a unit of stored heat in the 1820s used to describe the efficiency of steam engines—it is the heat needed to raise the temperature of a kg of water by one degree Celsius. Chemist Wilbur Atwater later extrapolated the calorie into American nutrition science as nutrition experts in the 19th century were concerned about undernourishment among poor laborers. At that time, they were most interested in learning which diets would promote the most workforce production at the lowest cost to the employer.
Atwater was particularly interested in measuring the energy (heat) value of foods based on the “sweetcorn scenario”. You eat corn one day and notice you haven’t absorbed all the corn the next day in the toilet bowl. He subsequently used this to determine the calorie content of macronutrients by subtracting the calories of stool from the calories of ingested food (e.g. 9kcal per gram of fat).
These calculations continue to make up the foundation of calorie counts on today’s food labels. However, this system only provides the calorie content of macronutrients and will produce calorie counts that are wrong—we don’t eat protein, carbohydrates and fat individually. We eat food.
By the 20th century, however, weight loss became especially popular among women chasing “ideal” body shapes presented in magazines and movies. In 1918, physician Dr Lulu Hunt Peters who struggled with weight herself caught onto the concept of calorie counting and capitalized. Through her best-selling diet book Diet and Health: With Key to the Calories, she provided a self-sufficient solution to obesity: create a negative energy balance through calorie restriction.
Her book was the first weight-loss book to become a bestseller and not long after Dr. Peters became the mother of calorie counting within our current diet culture.
However, many of her key philosophies about calories and weight loss remain with us today and continues to perpetuate weight bias in our current culture. For one, she influenced the absolute evaluations of food based on calories:
“Hereafter, you are going to eat calories of food. Instead of saying one slice of bread…you will say 100 Calories of bread…” (p.10)
She also influenced the current Calories in – Calories out model, explaining the importance of exercise to balance food intake energy. During a time of malnutrition and food rationing, she also saw people who did not have control over their weight as morally suspect.
Calorie counting within nutrition science is a weakly supported scientific concept. It has not translated well when applied to weight loss because our bodies are not calorie calculators, and our fat stores are not lifeless storage containers. Trying to apply the first law of thermodynamics to this is almost comical. However, it is the application of calorie counting to weight loss that should make us all re-think the concept right now. Unknowingly to Dr. Peters at the time, calorie counting was ultimately rooted from her own weight bias.
Considering all the above, how do useful, accurate and relevant do you feel calorie counting is?