Pizza, popcorn and chips: such delicious, carb-laden snacks have an uncanny ability to seduce even the healthiest eater with the strongest will power.
As British documentary host, Hugh Fearnley-Whittingstall of the series Fat Fight explains: snacks are "those seemingly innocent treats that come with a big cost to our health".
The fact is snacking every day is a relatively new phenomenon.
“Fifty years ago, most people just ate three square meals a day and that was that,” Fearnley-Whittingstall explains in the final instalment of the health series, , now available to stream on .
“The idea of snacking between meals was jumped on by marketing executives as a clever way to boost sales of a whole bunch of new products: and it worked. Today, the snack market is worth 18 billion dollars a year, and it has us completely hooked.”
The idea of snacking between meals was jumped on by marketing executives as a clever way to boost sales of a whole bunch of new products: and it worked.
But what Fearnley-Whittingstall wants to know is why: why have masses of people living across wealthy countries like Britain and Australia developed an insatiable taste for non-healthy, savoury snacks?
Fearnley-Whittingstall discovers the answer is multifactorial. As well as having much to do with false or misleading health claims featured on some snack labels and fancy marketing plans to make snacks appear more appealing, there’s one major scientific reason you find snacks biologically irresistible.
Apparently, your brain finds it hard to resist anything that combines both fat and sugar: a combination found in many carby snacks.
a geneticist with around 20 years’ experience studying obesity and the brain control of food intake, weighs into the discussion.
“Now, you have to remember that sugar is a carbohydrate,” Dr Yeo tells Fearnley-Whittingstall on Hugh’s Fat Fight. “It’s a simple carbohydrate, but it is a carbohydrate.”
Dr Yeo reminds us that although chips (or crisps) are simply potatoes and fat, they’re also nutritionally comprised of carbohydrates and fat: the combination, which makes food irresistible.
Hugh Fearnley-Whittingstall discovers the fat-sugar combination that makes snacks so hard to resist. (Image: supplied) Source: Supplied
“The response in the brain that you get from these foods are substantively different than the ones you get from just high sugar or high fat by itself.”
Dr Yeo adds that humans may be wired to have the taste for the sugar-fat combination, like human breast milk as one of the few naturally occurring substances that are high in sugar and high in fat.
“We are almost evolutionarily designed to love these foods more than stuff that is purely high in sugar or purely high in fat.”
Research, led by Yale University and published in the journal , adds weight to Dr Yeo’s explanation.
The study of 206 adults found that the reward centre of the brain tends to values foods that are high in both fat and carbohydrates (processed foods) more than foods containing only fat or only carbs.
It also highlights that people are better able to estimate the energy density of fat, compared to foods rich in carbohydrates and fat. This implies that the interaction of fat and carbohydrates may hijack our body’s inborn food consumption signals.
We are almost evolutionarily designed to love these foods more than stuff that is purely high in sugar or purely high in fat.
Australian-led research published in has also revealed that brain changes, commonly seen in drug addiction, are observed in animals that become obese when fed a diet high in fat and sugar (similar to common fast foods like burgers and pizza).
The research, headed by , showed that when animals were fed a diet of fat and sugar, only a third went on to develop obesity.
Researchers then compared the brains of the obese animals to animals that remained a healthy weight.
The scientists could see that the brains of obese rats had similar impairments to those seen in drug addiction, like the inability to regulate eating behaviour. The study suggests that the brain region, called the Nucleus Accumbens, was 'hijacked' by
Dr Yeo explains that manufacturers now have a term of the perfect combination amounts of fat and sugar to make a product food popular: the bliss point.
"They have scientists that work for them to actually find the foods that trigger us the most,” says Dr Yeo on the show.
“It's probably one of the key reasons why we are eating two to 300 calories more than we should a day, therefore driving the obesity problem.”
To find out what happens when Fearnley-Whittingstall challenges some of the marketing claims made by snack producers, watch .
