Your Full Belly is a Lie

By Andrew Broadley

We have all done it. You eat and you eat and you devour an absurd amount of food until you feel full up to your chest. You unbutton your pants and you groan as you lower yourself onto a sofa. Your life seems to be in freefall. That is until you hear the call for dessert. Suddenly the ‘chest full’ sinks back down to your stomach and then sinks a little more so now you are more like, stomach satisfied. You get back off the sofa and go and enjoy something so sickly sweet that only a few moments earlier you yourself couldn’t have imagined. As a child I used to tell my mum I was full and when she told me there would be no dessert I would complain that only my dinner stomach was full.

“I’m a baby cow mum, but I have two stomachs not eight; one for dinner, one for dessert.”

And as ridiculous as this was (this isn’t how a cow’s eight stomachs operate) it does point to a notion that seems to be true among many of us. We always have room for dessert. I’m not even really into sweets, I would choose savoury over sweet every day. But even so I often feel myself craving a sweet night cap after my meal. No matter how full I feel, I find it hard to resist popping down to the convenience store and grabbing myself a Choc Bar (New Zealand’s premium low cost ice cream, not up for debate). And it is something I get angry at myself all the time over. I was so full, I didn't need this ice cream. I wasn’t hungry, or was I? I can’t even tell anymore. Luckily, I now know I can blame science for all of it.

Sensory-specific satiety is an evolutionary trait that essentially tells our body we are full before we really are full. It kicks in when we eat too much of the same flavour or food group and is designed to stop us from over eating that one thing. Now a long time ago this was to help us have a balanced diet. To not eat a dinner of only rice or of only meat, but to have a variety of food groups and in turn, a variety of nutrients. It was your brain's way of keeping you healthy by telling you that you are full when really, your brain was just super sick of that one flavour. But this was before the days of affordable and available takeout and snacks and sweets on every street corner. Now no matter what I eat I seem to be left craving its polar opposite. I could eat a dinner of candy and still be left wanting a fried chicken chaser (I swear I would never actually do this). It also explains how we can push through so many plates at Christmas lunch or a buffet. The variety allows us to eat beyond what our body would usually tell us if we were having a single meal. In some ways it is almost encouraging us to keep eating, our brain remains interested in the variety it is being presented with and encourages us to keep going. It also explains how after two bowls of pasta I can get my arse back up off the couch and have a piece of cake and some ice cream too.

Studies have shown that if you force people to eat a bunch of the same food they will become ‘full’ far sooner than those who are given a variety of meals, regardless of how excited they are for the meal. Essentially, it could be your favourite meal but you will still eat less than if you had it with a variety of other foods, simply because your mind is being a filthy little liar. Additionally, the test group who were fed the same meal till they couldn’t eat another bite was then given ice cream, which they all then went on to eat.

This idea that people get sick of a single flavour and stop eating isn’t really that groundbreaking, but what is interesting is that your brain is doing this same thing even when you don’t realise. Your full belly is a lie, an evolutionary one. It is the reason why Neapolitan ice cream can be devoured in higher quantities than all the others (unless you are one of those sociopaths who solely scoops all the chocolate). It’s also why french fries with condiments are irresistible whereas french fries with nothing is just kinda, meh.

So, next time you hate yourself for overindulging, remember, you didn’t over overindulge at all. Your brain is a liar and I could really use a Choc Bar right about now.