Why is calorie counting a waste of your valuable time?

Written by Liz Withyman
September 6, 2023

It’s not a simple equation

We were brought up with the concept that to lose weight, you had to follow a simple equation: you needed to eat fewer calories and burn more calories in the gym. If you ate a 200 calorie Kitkat, you’d need to work out until you’d burnt 200 calories. This seemed logical, right? Well, it’s not that simple!

Let’s look at the calories OUT part of the equation first, and then we’ll look at calories IN.

Reasons why calories out are complicated

‘You can’t outrun a bad diet’

You may have heard the phrase, ‘you can’t outrun a bad diet’…it’s correct, and here’s how we know this.

Herman Ponzer, Professor of Evolutionary Anthropology, studied the energy expenditure of one of the last hunter-gatherer tribes on earth, the Hadza tribe in Tanzania, whose lifestyle gives us an insight into how humans evolved.

Hadza people get 5 to 10 times more physical activity every day than most people in the US and Europe, so the scientists studying them were shocked to find that they burn the same number of calories as the average Westerner.


It turns out that if we humans burn more calories in one way because we move more, our bodies adjust by spending fewer in others. It makes sense because in order to survive, human bodies needed to find ways to conserve energy.

We have a more-or-less fixed daily calorie budget which varies between individuals mainly according to size – the bigger you are, the more calories you need.

One factor we do have some control of is the amount of lean muscle mass we carry – the more you have, the more calories you’ll burn.

When we use up more calories on moving, our metabolism adapts and we use fewer on other metabolic processes, which is partly why moving is so good for us.

Why exercise reduces inflammation and stress

Regular exercisers have less budget left for unnecessary inflammation, the root of so many diseases from cancer to depression. And there’s less energy for producing adrenaline and cortisol, so they’ll have a lower and shorter stress response. A study on young moderately-depressed women showed that 8 weeks of jogging resulted in no change in weight but their bodies produced 30% less adrenaline and cortisol each day.

Exercise can help weight loss indirectly

So because of adaptation, aerobic exercise per se is not a good weight loss tool after the first three weeks or so of a new exercise habit. However, I don’t mean you shouldn’t do it as part of your weight loss strategy. It may help you to lose weight indirectly eg by lifting your mood and therefore reducing emotional eating and improving your sleep.

And, studies show that exercise is helpful in keeping the weight off once you’ve lost it.

And because more skeletal muscle mass is a factor in determining your metabolic rate, strength training is a route to burning more calories long term. Just don’t bother trying to count the calories you’ve burned because it doesn’t work like that!

Reasons why calories in are complicated

Calories on packets are just rough estimates

Now, what about calories in? The main point here is that you need to treat calorie estimates on packaging or elsewhere is just that – rough ESTIMATES – in some cases wildly inaccurate – and therefore, again, not worth counting! What do I mean by this? Surely when that Kitkat says it contains 200 calories, it must be true?

Here’s some history. Many of the calorie measurements still in use today were undertaken by a nineteenth century scientist called Wilbur Atwater, who burned food and what was excreted by people who ate the food, to calculate its calorie content. Some estimates are now thought to be significantly inaccurate, eg the calories in protein were overestimated by around 30%, because historical calculations didn’t take into account the fact that we use more energy to digest protein than with fat or carbs.

The ‘food matrix’ complicates calorie calculations

And, as well as the fact that we are relying on an inherently inaccurate method of calculating calories, something called the food matrix makes this even more complex. For example, although this is NOT reflected on the packet when you buy them, almonds are much more calorific when they’re ground, because of the absorbability of the fat. And a bloody steak is lower calorie than the same steak well done because cooking affects calories too. And foods interact with each other depending on how they’re combined. It’s incredibly complex and can’t be reduced to a number!

Restaurant menus

And you know those calorie estimates on restaurant menus? Don’t trust them! The actual calorie content has been shown to deviate up to 200% from the number on the menu. And it’s nearly always an underestimate.

We all respond to food differently

And after all of that, even if you WERE to get a good estimate of the calorie content of a food, it would become meaningless when you realized how differently our bodies respond to food. The recommended daily calorie intake is 2,000 calories for women and 2,500 for men. But this makes no sense because we all have a unique metabolism.

Our metabolism is mostly not determined by our genes. More significant factors include how much lean muscle mass you have, your microbiome, how much sleep you had the night before, your age, gender, and your fasting intervals…so this too is incredibly complex and undermines the model suggesting a general daily calorie allowance.

All of which is why calorie counting fails so many people

So as you can see, there are a number of serious flaws with the calorie counting weight loss model, so it’s not surprising that it fails millions of people throughout the Western world. The fact that many diet club members remain so for years or keep having to go back, time after time, speaks for itself. For so many people, it’s not sustainable and often results in years of yo-yo dieting.

And even worse, this focus on calories often leads to choosing food on the basis of their calorie content rather than quality. The food industry makes millions out of low-fat, artificially sweetened ultra-processed ‘diet’ food, advertising it as healthy when in fact usually it’s had all the natural fibre with its fabulous phytonutrients taken out, and sugar or petrol-based artificial sweeteners added in…horrible for your gut, horrible for your insulin regulation, horrible for your energy levels, and for the vast majority of people, horrible for your weight.

Be mindful of the energy density of food if you want to lose weight

So hopefully you’re convinced that it’s a waste of time to try to carefully count calories out or in for the purposes of weight loss, and dangerous if you choose foods on that basis.

Having said all that, I’m not saying that some foods aren’t more energy-dense than others…clearly that’s true and you will need to bring a mindfulness about that to your food choices if you’re wanting to lose weight.

Just don’t get hung up on the numbers.

Liz Withyman

Liz Withyman is an ICF-registered ACC (Associate Certified Coach) who trained with the Coaches Training Institute, the most rigorous and respected coach training in the industry. She runs her online Coached Intermittent Fasting Program 7 Habits for a Vibrant Life several times a year. 

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