Nutrition - When you eat sugary foods, do you struggle to stop?
People regularly share that once they start eating something sweet it feels
impossible to stop. Or that when they try to reduce their sugar intake their
tastebuds have other plans. Often they feel ashamed of this, and berate
themselves after eating more than they intended to.
But it’s not a lack of willpower driving this.
There are biochemical reasons why sugary foods and drinks are so desirable, and
why it can feel so hard to stop after a small taste.
Humans have evolved to love the sweet stuff. This is partly because
historically the bitter foods we would find when hunting and gathering were
more likely to be poisonous and partly because sugar is rich in energy
(calories) and provides fuel that our brain uses (glucose).
For many of us in more recent decades, food is abundant. Yet it wasn’t that
long ago that food shortages were a key threat to our survival. In a world
where food may be scarce, it makes sense that we would be drawn to, seek out
and eat more of the sugary quick energy-fuelling foods. Plus these ‘foods’
weren’t available from a supermarket shelf – they could be hard to get our
hands on. Yet, this evolutionary quirk can bite us in the
modern world where there is an abundance of food on offer—particularly lots of
ultra-processed foods containing highly concentrated sugars.
Sweet foods and drinks give our brain a great big hit of a chemical called
dopamine. This activates our brain’s reward system, essentially
communicating that this is definitely something we want to experience again.
When we consistently overconsume sugar, we are activating this reward system
again and again—and so our brain starts to adapt. It’s like we build up
a tolerance and you may find yourself desiring more and more to get the same
feel-good response.