What happens when you salivate over potato finger chips? Like other products that are part of the modern American diet, one potato chip can blend a range of ingredients that would illuminate the brain-reward neural circuitry. It would also stun into silence the 'Stop' signals that should tell us that we have eaten enough.
These are the 'hyper-palatabe' foods that are processed products or sweets blending interesting ingredients such as fat, sugar, carbohydrates and sodium. What exactly is this sinful food? An article published in Obesity looks at the particular metrics that translate into hyper-palatable foods. Most American products could be clubbed into this category.
"Multiple documentaries have pointed out that food companies have very well-designed formulas for these types of foods to make them palatable and essentially enhance consumption," said lead author Tera Fazzino, assistant professor of psychology at the University of Kansas and associate director of the Cofrin Logan Center for Addiction Research and Treatment at KU's Life Span Institute. "But these definitions are virtually unknown to the scientific community, which is a major limitation. If there's no standardized definition, we can't compare across studies -- we've just typically used descriptive definitions like 'sweets,' 'desserts' and 'fast foods'."
Fazzino and her KU coauthors -- Kaitlyn Rohde, research assistant at the Cofrin Logan Center and Debra K. Sullivan of the Department of Dietetics and Nutrition at the University of Kansas Medical Center, drafted criteria for hyper-palatable foods by setting up a literature review, and then leveraging nutrition software. They checked out their criteria vis-a-vis 7,757 food products in the US Department of Agriculture's Food and Nutrient Database for Dietary Studies (FNDDS).
"We essentially took all the descriptive definitions of the foods from the literature -- for example Oreos or Mac and cheese -- and we entered these one by one into a nutrition program that is very careful in how it quantifies a food's ingredients," said Fazzino. "This nutrition software essentially provides in fine-grained detail a data set that specifies how many calories per serving are in this food, and how much fat, sodium, sugar, carbohydrates, fiber and all sorts of other things."
According to the team, the food items in their literature review increased palatability, especially as "the synergy between key ingredients in a food creates an artificially enhanced palatability experience that is greater than any key ingredient would produce alone."
These synergies that had specific characteristics applied to three clusters. Firstly, when fat and sodium are blended, as in hot dogs or bacon; secondly, when fat and simple sugars such as cake and ice-cream are put together; and thirdly, when carbohydrates and sodium, such as crackers and popcorn are combined.
"Essentially, we wanted to identify foods that appear to cluster together with what appeared to be like similar levels of at least two ingredients, because that's the theoretical basis for inducing the synergistic palatability effect," said Fazzino. "Through a visualization process, we were able to see there were essentially three types of foods that appeared to cluster together in terms of their ingredients."
So how pervasive are the hyper-palatable foods? Scientists discovered that 62% of foods in the FNDDS seemed to meet the requirements for at least one of the three groups. About 70% of the foods, such as meat or egg dishes, show fat and sodium content. Most of the 25% of the hyper-palatable foods are quite high in fat and sugar, while 16% indicate carbohydrates and sodium. There were foods that also happened to figure in more than one cluster, yet those are just less than 10% of the foods.
Strangely, some products that have been classified as "reduced" or "no fat, sugar, salt or calories" feature in only 5% of hyper-palatable foods. Moreover, among all the products classified as such in the FNDDS, about 49% meet the requirement of being hyper-palatable.
The latest plan is to compare the ubiquitous hyper-palatable foods in the US with those of other nations. In a recent application for a grant to compare American and Mediterranean foods, Fazzino hopes to spread more awareness.