Topics

Join us!

If you enjoy writing about science, then join our team of student writers to get your work published on our site!

Apply!

The Science That Shapes Our Diets

By Hannah Burke

Photo credit: Pixabay

“Once you pop, you can’t stop”, “the irresistible crunch”, “finger lickin’ good”; the implied messages of the junk food industry advertisement slogans are clear – ‘our foods are addictive and will leave you craving more’. It is no wonder these industries are so confident with their extravagant claims; behind closed doors scientists and engineers are secretly working hard to chemically manipulate packaged foods, ensuring our hands continue to reach for that second and third biscuit.

Every single one of us, to some extent has experienced the unrelenting urge to consume a favourite processed snack. Studies conducted in the US, Canada and Great Britain have found that a staggering 100% of young women and 70% of young men upon questioning, had experienced one or more food cravings at some point in the past year. A food craving is defined as an intense desire to consume a specific food which is a separate phenomenon from hunger. Whilst there is no single explanation for this behaviour, food cravings have been associated with the release of endogenous opiates – chemicals produced by the body which produce feelings of pleasure and decrease our perception of pain. But are cravings necessarily no one’s fault but our own inability to resist temptation?

Playing With Food

Some of the biggest industries are now utilising fMRI brain scanning techniques to investigate how we react neurologically to certain foods. Studies have revealed three reward centres of the brain as showing significantly greater craving-specific activation – the hippocampus, insula and caudate. Perhaps most intriguingly was that all three of these areas were also activated during drug addiction studies. The complex science behind the cravings of junk food are increasingly being unveiled by scientists and the media, with the leading food industries deemed the key culprits and manufacturers of the global obesity epidemic. New York Times journalist Michael Moss, who spent three years investigating how the food giants have advertently ‘hooked us’, argues “it is the precise amount of sugar or fat or salt that will send consumers over the moon”. Using complex regression analysis and charts, scientists are able to calculate the optimal “bliss point” - that is the precise amount of each of these ingredients which is required to leave the consumer craving more. Three parts of the brain involved in food cravings—the hippocampus, insula and caudate are identical to those involved in drug addiction.

Tricks Of The trade

Fat adds bulk and texture to foods and to the manufacturer’s advantage can stimulate overeating. One of the most significant advantages of using fat in foods is in its ability to coat the tongue, masking acidic flavours whilst concurrently enhancing more pleasurable, subtle, aromatic flavours. Nestlé has reportedly altered the distribution and shape of fat globules, modifying their absorption rate and what is known to the industry as the “mouthfeel”; this is the way in which a food interacts with the mouth. Altering the shape and structure of ingredients in food products is by no means a rare phenomenon. Cargill, a leading supplier of salt in the UK, has reportedly changed the shape of their salt to a fine powder which stimulates taste buds faster. Also, enhancers can be added to sugar to increase its sweetness by up to two hundred times its normal strength.

Fat globules in water. Photo credit: Pixabay

Seeing Is Believing

But it is not only the taste or structural properties of the food itself which has these extraordinary craving -inducing abilities, arguably the entire sensory experience of eating affects cravings, with just the sight of food alone exciting the brain. Unilever, one of the world’s largest food manufacturers, undertook studies which confirmed the role of sensory perception. When asking subjects to smell a milkshake; the same pleasure zones of the brain were activated as to when they were physically tasting the drink. Additionally, the team amplified the noise made by potato crisps whilst they were being eaten and found the noisiest crisps were rated amongst the participants as being both fresher and crispier, therefore allowing manufacturers to design the most satisfying amount of “crunch”.

Trigenemial Sensations: An Area For Food Innovation

We sense food through a nerve called the trigeminal, which is located behind the mouth near the brain. Nerve endings transmit sensory information such as temperature, texture and shape from the lips, gums, teeth and jaw to the brain. The food industry places considerable emphasis on selecting ingredients which stimulate the trigeminal nerve. For example citric acid for it’s tingling effect and menthol for it’s cooling sensation. Michael Nestrud, a sensory science PhD candidate at Cornell has suggested using spilanthol in soy-based yoghurts for its mouthwatering properties.

Soy based yoghurt is rich in spilanthol. Photo credit: Pixabay

A Consequence Of Our Own Desires?

Inevitably food manufacturers claim they are simply fuelling the ever increasing consumer demand of fast, convenient foods and arguably it is true, many of the additives used in processed foods are not there to primarily induce cravings. The use of sugar by Al Clausi in the 1980s to prevent bacterial growth in moist conditions, has since become a well -established method to maintain an extended shelf life. It is therefore inevitable that processed foods will need chemically altering to a certain degree, especially to disguise the taste of preservatives. Food manipulation may not be entirely bad for us either, Nestlé has taken encouraging steps to address the obesity crisis by creating reduced fat ice-cream without compromising on the taste or texture of full-fat varieties. The secret? Healthier “encapsulated” oil like sunflower oil is encased by sugar or protein molecules and dried into a powder which can mimic the same mouthfeel as saturated fat, fooling customers into thinking they are eating fattier foods when in fact the risk of heart disease was reduced.

Photo credit: Hannah Burke

Food For Thought

It is without a doubt that processed foods are perfectly engineered to entice us. Complex science lies behind their taste, texture, aroma and packaging. It is this combined effect which enables food manufacturer’s to stand their ground in the battlefield of the grocery aisle and win a place in our shopping trolleys time after time. Positive food modifications which offer healthier options are in development, but ultimately somebody is likely to save the world from obesity or any of the other ill effects of processed foods, it probably isn’t going to be in our lifetimes. The discovery and potential exploitation of multi-sensory food perception has the power to alter the perception of food. So—perhaps we should be focussing on technologies which stimulate the mind, and not just the mouth of the consumer?


Copyright © Reaction Science 2019