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Why Counting Calories and Macros Isn’t Exact

Updated: Oct 4, 2021

Labeling only shows the averages

When a new food product that falls under the FDA comes out, the food scientists who work on it use what’s called a calorimeter to determine how many calories and macros are in the food. When they do this, however, they grab a set number of the product, and run the test over and over again until they have a large enough data set to determine an average. This means that when you purchase that product and read the label, it may not be exactly what you think it is, it is likely not that exact number, but an approximation

We don’t absorb everything we eat / consume

Depending on the food, the person, and their gut, the amount of calories absorbed will vary wildly. Most people know that each macronutrient carries a different number of calories per gram, with fat having 9 and the carbohydrate and protein both containing 4 each. Side note, alcohol is reported as 7calories per gram due to the fermentation process. These are just averages though for each macro and then there are specific foods that don’t follow these numbers and are only absorbed at lower rates, great examples are nuts and seeds

  • Almonds

  • Cashews

  • Pistachios

On the opposite side of the spectrum are the fiber rich foods. These foods are absorbed more than the average and the formula represents. This means your body will take in more than expected.

  • Tomatoes

  • Kale

  • Cabbage

  • Oranges

  • Black beans

Does this mean you need to know exactly what percentage of each food is broken down? No! This means that we just need to be aware of this and that again, counting calories and macros is not as specific and perfect as people make it seem.

The average error on foods is about 10%. This is definitely something to consider.

How the food is prepared greatly changes the calories and macros

When we prepare food, there are a few reasons, with the biggest thing being safety and health and the other part being the bioavailability (how many calories we can get from the food). The cooking of food usually increases the bioavailability, in some cases almost doubling it, with an increase of 90% a baked potato is a great example. Other foods include eggs being boiled which increases the calories by 34%. This is not accounted for on the food labels and will definitely change the calories consumed per day. Even if you prepare the foods in the best ways possible, it still can have a major impact on your calorie count.

This is another reason why it is so important that instead of obsessing on the calorie count, we focus on creating good habits, use the hand portion approach and work to make small changes consistently. We then take the data and results over time and again make small changes.

Total error – up to 90% on certain foods, specifically increasing the calories from the food prep.

Each individual absorbs things differently

This will play another huge role in what is being broken down and utilized by each person. The type of bacteria in a person’s gut can play a huge role in almost every aspect of their health and performance. This can be read about in more detail HERE in our article on gut health and the microbiome. The main takeaway here though, is that people with a higher proportion of Firmicutes bacteria will, on average, absorb an average of 150 calories per day compared to those who have more Bacteroidetes. This can have a great impact on the number of calories that each person will need and also effect their calorie count for calories in versus calories out.

*There are things we can do to effect your gut microbiome and if you are worried about this, then we can discuss further how to implement those changes.

People (who don’t use the hand portion system) suck at portion sizes

The research suggests that for each time a person “measures” something, they are wrong 2 out of every 3 attempts. This can add up to huge amounts of calories over the course of a day. If a person is wrong on 66% of their measurements and they are eating calorie dense foods (peanut butter and other performance fats for example), this can quickly add hundreds of calories.

This unintentional increase in calories now yet again adds another layer to the problem where if the person is tracking calories and macros they are tracking the wrong ones. This is another reason why we recommend the hand portions, it often works better long term, specifically when traveling or out to eat, compared to measuring/weighing or “eyeballing” it.


With all of that being said, these things can all add up to equal a 25% difference in calories counted vs eaten. So we know that this is NOT the incredibly accurate way to do things and that there are times to certainly track metrics, but we need to know whether or not the juice is worth the squeeze (sorry, couldn’t help it).

If you are going to track your calories and it helps you, THAT’S FINE, just make sure you know that there will be some mistakes and numbers won’t always add up perfectly.

Feeling overwhelmed by the idea of counting calories and macros? No worries! Go check out our article about how to use the hand portion chart and better systems besides just counting calories and macros!

Do you want to learn more about how to meal plan, build better daily habits and be your best self without having to track every calorie? Then have our staff of dietitians, coaches and counselors be your allies! Click here to speak with our staff and get more help on your journey today!


Burrows, Marian. “Losing count of calories as plates fill up.” The New York Times. April 2, 1997.

Carels RA, Harper J, Konrad K. Qualitative perceptions and caloric estimations of healthy and unhealthy foods by behavioral weight loss participants. Appetite. 2006 Mar;46(2):199-206.

Carels RA, Konrad K, Harper J. Individual differences in food perceptions and calorie estimation: an examination of dieting status, weight, and gender. Appetite. 2007 Sep;49(2):450-8.

Feinman RD, Fine EJ. “A calorie is a calorie” violates the second law of thermodynamics. Nutr J. 2004 Jul 28;3:9.

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