There’s a reason you crave salty foods when you drink. And it’s driving weight gain

Ever wondered why a cheese plate and a glass of chardonnay pair so perfectly or why people crave salty fries or pizza with their beer? It’s called the aperitif effect.

Refined as the aperitif effect sounds, the system driving it is even more sophisticated.

Our bodies have a hankering for protein foods when we drink because the enzymes found in protein help them process the alcohol.

Our bodies associate salty, umami-flavoured foods as protein-rich. But, in the modern food environment, where these flavours can be added to ultra-processed foods (UPFs), our mouths are getting what they crave, but our bodies are not, so we are driven to keep eating as our bodies seek the protein hit they need.

This is the finding of a fascinating new paper, published in Obesity Reviews. Along with another new paper, published in Science, they help to explain why we are motivated to eat certain foods.

“The findings have wide-ranging implications, even extending to an understanding of human obesity,” say University of Sydney professors Stephen Simpson and David Raubenheimer.

The protein leverage hypothesis is the idea that we crave protein over other nutrients because it is vital for muscle repair and metabolic function, and we can only get essential amino acids from our diet.

This biological need drives us to eat as much food as we need to meet our protein requirements. While this behaviour is widely recognised, the mechanism is poorly understood.

So, the new study in Science looked at flies – which have the same appetite for protein as humans – to understand how the system works.

They found that cells in the lining of our gut sense when we are protein deficient and send signals to the brain that we need to consume more. In response, our brain heightens the sensitivity of nerves in the mouth to flavours it associates with protein: and we start craving savoury, salty, umami foods.

It’s an exquisitely evolved system, says Simpson, who came up with the protein leverage hypothesis alongside Raubenheimer two decades ago.

In a whole food environment, it’s difficult to overeat, he explains because once we get our protein fill, our bodies dial down the cravings and dial up the signals that we’ve had enough.

“That’s why, of course, high-protein diets lead to weight loss because people don’t eat as much because your body says, ‘no, you’ve got enough, don’t eat any more’,” Simpson explains.

But, when the system is hijacked by protein decoys (foods with savoury or umami-flavours that are low in protein) it takes a lot more food to get those signals and for the cravings to be