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Calories & Cavemen: The real reason why diets fail

Calories & Cavemen: The real reason why diets fail

We get it. Diets are tough.

You spend days, weeks, even months carefully watching what you eat, only to eventually cave into cravings.

You’re far from alone on this one. More often than not, diets fail to deliver on those sought-after health goals.


Does it all just come down to willpower and grit, or is there more to our relationship with hunger and food cravings?

In studying the science behind hunger, we’ve learned that willpower is locked in a constant battle with thousands of years of evolution… And it’s not a battle it can always win on its own.


Hunger – great for cavemen, bad for us


In our world of on-the-go everything, calorie rich snacks and outrageous meal portions, it’s easy to forget that we humans are built for a feast and famine diet.

When millions of years of hunter-gatherer evolution abruptly meets the modern western diet, overeating isn’t far behind.

The problem? Simply deciding to eat less isn’t as easy as it sounds.

For starters, when you reduce your calorie intake by around 20%, your body goes into survival mode - an evolutionary response designed to keep you alive during times of famine. *

This survival mode in turn kickstarts two biological process – a slowdown of metabolism and our old nemesis, hunger.

Firstly, let’s talk metabolism.

When food intake is restricted, your body reacts by reducing the calories you burn. If you’ve ever felt tired, hangry, or less focussed when dieting – that’s a slowed metabolism in action. This instinct was great for conserving a hunter-gatherer’s energy on the Savannah and bridging the feast-to-famine gap, but it’s less useful in modern society where there’s an abundance of food wherever you turn.

Secondly, your brain – still stuck in its primal, caveman ways – activates hunger to focus your attention on your next meal.

Contrary to the commonly held belief that hunger levels decrease over time on a restricted diet, the opposite has been found to be true. Research shows that after 8 weeks on a reduced calorie diet, your hunger levels increase by a whopping 75% from their baseline. *

Quite simply, your body has a calorie intake baseline, if you dip below that mark, these two responses - slowing your metabolism and increasing your hunger - kick into gear

This is what our willpower is up against: a primal instinct for survival.

It doesn’t seem a fair fight, does it?


Science of Hunger


So, what can we do?


We’re dealing with powerful biological forces on a day-to-day, minute-by-minute basis. What can we do about it? 

We need to find ways of working with our hunger, rather than against it.

For starters, acknowledging and understanding our individual differences can help.

Our health and wellbeing plans need to reflect the realities of our bodies and lives. What works for one person might not work for another. Likewise, finding our own personal routine that delivers results will take time and some experimentation.

It’s also the small changes, reinforced over time and repetition, that really deliver results. For those in need of a helping hand, tools such as calocurb can help you manage food cravings by supporting healthy snacking and portion control choices. 

Most importantly, let’s be kinder to ourselves.

We need to acknowledge that willpower doesn’t always work on its own – and that’s ok.

We’re up against incredibly powerful evolutionary forces inside all of us. Understanding the battle between willpower and evolution when dieting is the first step on the road to making health and wellbeing choices that deliver real results.

So, let’s not beat ourselves up. Often our primal urges will be stronger than our ability to resist them.

That doesn’t make us failures, that makes us human.



*J.-P. Chaput, É. Doucet and A. Tremblay. Obesity: a disease or a biological adaptation? 2012

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