Content warning: I kept this post free of calorie counts but do use the word “calorie” to make certain points. The linked references may contain stigmatizing language - I am doing my best to update all posts with the best resources I can find, but am doing the best with what’s available. If any of the language used is triggering to you or feels uncomfortable, I encourage you to protect your mental health & skip this post.
One of the biggest myths in eating is the idea of “calories in, calories out.” That by simply “balancing” or manipulating the amount of calories we take in with the amount of calories we burn is a direct path to weight change, health, and happiness. My goal for this post is to highlight some of the (several) reasons that calorie counting is unnecessary and calories in, calories out is scientifically unsound (and likely damaging to our relationship with food).
What actually is a calorie?
First, let’s just establish some base knowledge - when calories are painted as an entirely negative concept, it’s really easy to forget what they are and how they serve us. A calorie is simply a unit of energy - the amount of energy that is required to heat 1 kilogram of water by 1˚C. I use calories and energy interchangeably - typically in client sessions, I’ll use “energy” to help remove some of the stigma that comes with the word “calorie” but in this post, since “calories in, calories out” is the true name of the diet concept, I’ll use that term too.
We Can’t Possibly Know How Many Calories We’re Getting
Think that a quick equation and a nutrition facts label ensures total confidence in your calorie knowledge? Think again - this system has a lot of holes in its logic.
Food Labels Are Flawed
The Food and Drug Administration, which regulates things like nutrition facts labels, nutrition claims, and accuracy of labeling, sets certain standards for the information on the nutrition label. Theoretically, this is to reassure customers that they are, in fact, eating what they are told they’re eating (and in the case of things like food allergies, labeling is really important and lifesaving). But for certain nutrients and total calories, the FDA allows a margin of 20% accuracy. This means that if a facility is to be audited/inspected by the FDA, the FDA will conduct its own nutrient analysis on a food and compare it to the company’s nutrition label. The ratio of the measurement to the label has to be within 120% or less (100% would occur if the two were exactly the same). (1)
“...the ratio between the amount obtained by laboratory analysis and the amount declared on the product label in the Nutrition Facts panel must be 120% or less.”
We All Metabolize Food Differently
There are a lot of factors that go into how each of us absorb energy from food. A helpful way to frame food and drinks that provide energy (calories) is to think of these items as “potential energy” - not necessarily the exact amount of energy we extract (I love this phrase from Body Respect).
Here’s some things that affect how we absorb and utilize energy from food:
The microbiome | The bacteria lining our gut need energy too! Simply put, they’re conveniently located to use some of our food/calories before we absorb it for ourselves. This comes into play for all of us differently - two people can eat the same food and get completely different amounts of energy.
Genetics | Very broadly speaking, our individual genetic makeup affects how we store and use energy - this is different for each person and different as time passes, since food, movement, and other lifestyle factors can affect gene expression.
Medical conditions & disease processes | Insulin resistance (as in type 2 diabetes or PCOS), medications, thyroid conditions, pregnancy, disability, and more can all affect how we utilize food (and how we experience hunger and fullness cues). (2)
How much you’re enjoying food | A study of Thai and Swedish subjects showed that iron absorption was decreased after a blended meal (literally, put in a blender) than a meal of regular texture, likely due to a decrease in enjoyment and palatability. (3)
We Need Calories To Live
The metabolism and how the body uses calories isn’t simply exercise - your body uses the energy you eat to sustain life. The number of functions the body carries out every minute is long - breathing, blinking, thinking, moving, cell growth and repair, circulation, maintaining a heartbeat, digesting, producing blood cells, etc. It takes a lot of power to power a body! Intentionally reducing calories sets your body up to prioritize functions - and means some will fall by the wayside, like having a regular menstrual cycle, optimal innervation and blood flow to the gut (digestion slows down), or having trouble concentrating/thinking clearly.
Your Body Is Not A Calculator - Or a Bank Account
It can’t be reduced to a simple equation or balance sheet. The idea that we can adjust or control our energy stores by eating more or less than our calculated needs is an extreme oversimplification of the body’s functions.
Calories in, calories out makes assumptions about how the body works, including:
The body will passively accept not having its needs met
More calories = automatic weight gain and less calories = automatic weight loss
We have control over our weight
The body has the same exact needs every single day
In reality, the body contains so much more nuance than this simple concept could capture. Simply put, the body wasn’t meant to starve. When we’re not getting enough food, our bodies respond at several levels, including hormonal, to try to protect us from perceived starvation - bodies don’t care about the reason you’re undereating, they just know they’re not getting enough (never forget that regular, adequate access to food is a privilege). Diets aren’t meant to work, and it’s unproductive and harmful to try to force our bodies to exist outside of their natural weight.
Calorie Counting Is Not Without Harm
Calorie counting isn’t a neutral behavior or one without side effects. Calorie counting apps and tools can predict and reinforce eating disorder behaviors. (4,5) Use of nutrition factors labels may also predict binge eating and engagement in disordered eating behaviors. (6)
Having a hyperfocus on food, dichotomous (all-or-nothing, black-and-white, etc.) thinking around food (if I eat less calories than my goal, my day was a success - anything else is a failure), and using exercise to compensate for eating are not part of a healthy relationship with food. Trying to “save calories” for later or to make up for eating will likely result in extreme hunger and binge eating, perpetuating the diet-binge cycle.
In addition, the amount of calories recommended by most calorie calculators is far, far below what most adults need just to survive. It’s even below the amount used in the Minnesota starvation study (cw: calorie amounts). A STARVATION study.
Much like we know that calorie counting is likely harmful, we also know that intuitive eating is a predictor of holistically healthy (read: physically, mentally, AND emotionally healthy) behaviors. (7) Intuitive eating is not a diet, and it also doesn’t disregard health - it’s an approach to eating that supports a flexible and positive relationship with food without compromising mental health or encouraging disordered behaviors.
Talking about the harms of calorie counting and calorie restriction does not mean that there is never a time or a place to talk about calories, or that calories don’t exist. Working as a clinical dietitian, I used predictive calorie equations to calculate tube feedings - without hunger/fullness cues and the context of eating by mouth, this approach helped give me a basis to start a feed and adapt based on the patient’s needs as time progressed. Rough estimates may also be helpful in eating disorder recovery to help your dietitian support you in eating adequately and restoring weight if that is part of your care plan. There may also be times in your life when calorie information becomes neutral or a way to support your body knowledge in meeting your body’s needs - this is when it’s super helpful to unpack the motivation to know nutrition facts with your dietitian and recovery team.
In summary: there may be a time and place for some knowledge and use of calorie information, but that time and place is rare & not in the general population.
Ready to move away from calorie counting and find food freedom? Let’s work together and support you in finding a flexible and healthy relationship with food and your body!
Office of Food and Nutrition Labeling. Guidance for Industry: Guide for Developing and Using Data Bases for Nutrition Labeling. Food & Drug Administration. Published March 1998. Updated September 20, 2018. Available at: https://www.fda.gov/regulatory-information/search-fda-guidance-documents/guidance-industry-guide-developing-and-using-data-bases-nutrition-labeling#stat_5
Bacon L, Aphramore L. Body Respect. https://lindabacon.org/body-respect-book/
Halberg L, Bjöm-Rasmussen E, Rossander L, Suwanik R. Iron absorption from Southeast Asian diets. II. Role of various factors that might explain low absorption. Am J Clin Nutr. 1977;30(4):539-48. https://www.ncbi.nlm.nih.gov/pubmed/851082.
Lindardon J, Messer M. My fitness pal usage in men: Associations with eating disorder symptoms and psychosocial impairment. Eat Behav. 2019;33:13-17. https://www.ncbi.nlm.nih.gov/pubmed/30772765.
Levinson C, Fewell L, Brosof L. My Fitness Pal calorie tracker usage in the eating disorders. Eat Behav. 2017;27:14-16. https://www.ncbi.nlm.nih.gov/pubmed/28843591.
Christoph MJ, Loth KA, Eisenberg ME, Haynos AF, Larson N, Neumark-Sztainer D (2018). Nutrition Facts Use in Relation to Eating Behaviors and Healthy and Unhealthy Weight Control Behaviors. J Nutr Educ Behav. Mar;50(3):267-274.e1. doi: 10.1016/j.jneb.2017.11.001. https://www.ncbi.nlm.nih.gov/pubmed/29276019.
Romano, K. A., Swanbrow Becker, M. A., Colgary, C. D., & Magnuson, A. (2018). Helpful or harmful? The comparative value of self-weighing and calorie counting versus intuitive eating on the eating disorder symptomology of college students. Eating and Weight Disorders – Studies on Anorexia, Bulimia and Obesity. doi:10.1007/s40519-018-0562-6. https://www.ncbi.nlm.nih.gov/pubmed/30155857.