Why You Shouldn’t Count Calories, Part 2

I don’t agree with calorie counting as a dieting and weight loss method. In my previous post here. I went into how it doesn’t tell you about how nutritious the food is, and how it can become obsessive.  

In this post, I’ll be talking about how the calorie count on food labels are inaccurate and how they don’t consider calorie availability and the thermogenic effect of food. Hopefully this will explain further about how calorie counting doesn’t look at the whole picture.

This post was inspired by Dr Giles Yeo who has written a few books on calorie counting and dieting.

Food labels are inaccurate:

The calorie numbers on food labels are averages. They’re based on carbohydrates and protein being 4 calories per gram each, and fat being 9 calories per gram. These numbers were calculated 120 years ago and the science behind them was questionable.

In the USA, calorie labels are allowed to be +/- 20% off. This means that if a product says it’s 100 calories, it could really be 80 – 120 calories. This isn’t very helpful when you're aiming for a certain calorie amount each day.

The calories on food labels are averages and they can be inaccurate. They also don’t tell you how many calories your body will actually absorb and use.

Calorie availability:

Calorie availability is the number of calories absorbed after digestion compared to the actual number of calories in the food. It’s how many calories are available to be used for energy after digestion.

Some calories are more readily available than others which means you absorb more of them. Calorie counting doesn’t take these numbers into account.

Macronutrient	Calorie availability	Calories absorbed if eating 100 calories of macronutrient
Protein	∼70%	70
Carbohydrate	∼ 90%	90
Fat	∼ 98-100%	98-100

Processed foods high in sugar and fat are likely to have a high calorie availability. This is due to the processing which makes them easier to digest. So, you could be having foods like biscuits and be absorbing nearly all of the calories. While a more unprocessed food like a boiled egg wouldn’t have all the calories absorbed.

This leads onto my next point about the thermic effect of food (TEF) as calorie availability depends on how we digest and metabolise each macronutrient.

Thermic effect of food:

The TEF is the amount of energy it takes your body to digest, absorb, and metabolise the food you eat. This is essentially the energy used to break down your food and for your body to utilise it. Utilising the calories means either storing it or using it immediately for energy.

Protein has a high TEF compared to fat and carbohydrates. Protein has a higher TEF as there is a lot of chemical reactions that need to occur for the protein molecules to be able to be used as energy. For your body to turn the protein into energy, it needs energy to power those reactions. So, your body uses some of the calories from the protein to help the protein be digested.

This is also why protein keeps you full for longer. It stays in the digestive system for longer which makes you feel full. If a food is more processed, you use less energy digesting it and it won’t stay in the digestive system for as long.

The TEF is also different for everyone as we all have different rates of metabolism. Which means we won't all absorb the same number of calories.

Again, calorie counting doesn’t tell you anything about TEF and how many of the calories your body is able to use. it also doesn’t tell you which foods will keep you full for longer.

 

I hope this post has given you a greater insight into calorie counting and why it’s not the best way to diet or lose weight.

Key points:

• Calorie counting oversimplifies the complex process that your body goes through in the digestion of nutrients – not all calories eaten are absorbed.
• Calorie counts on food labels are averages and could be +/- 20% off.
• Overall, calorie counting isn’t the best method for weight loss.

 

I hope you enjoyed this blog post! I’d love to hear your thoughts below.

Bye for now! 👋

 

References:

Blog inspiration: https://mynutriweb.com/the-death-of-the-calorie/

Calorie inaccuracy research: https://pubmed.ncbi.nlm.nih.gov/27974598/ and https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3605747/

USA calorie inaccuracy: https://www.fda.gov/regulatory-information/search-fda-guidance-documents/guidance-industry-guide-developing-and-using-data-bases-nutrition-labeling

Calorie count on food labels: https://www.food.gov.uk/business-guidance/nutrition-labelling and https://ec.europa.eu/food/safety/labelling-and-nutrition/food-information-consumers-legislation_en and https://eur-lex.europa.eu/legal-content/EN/TXT/?qid=1583243043830&uri=CELEX:02011R1169-20180101

Thermic effect of food: https://pubmed.ncbi.nlm.nih.gov/31021710/