Heightened sensitivity to 'seventh taste' carbs leads to larger waist sizes
In what is being claimed as a 'world-first discovery', researchers from Deakin's Centre of Advanced Sensory Science (CASS) have shown that taste sensitivity to carbohydrates increases energy and carbohydrate intake, and leads to a larger waist measurements.
Lead researcher Professor Russell Keast said carbohydrates had long been assumed invisible to taste.
"It is typically sugar, with its hedonically pleasing sweet taste, that is the most sought-after carbohydrate," he said.
"But our research has shown that there is a perceivable taste quality elicited by other carbohydrates, independent of sweet taste."
Keast's research looked at two carbohydrates, maltodextrin and oligofructose, both found in common foods like bread, pasta and rice.
Initial testing by Dr Julia Low, an academic at Deakin's School of Exercise and Nutrition Sciences, showed that these carbohydrates could be sensed in the mouth.
CASS researchers then undertook a study to examine whether sensitivity to the carbohydrates was linked to the consumption of starchy foods.
The study, published in the Journal of Nutrition, looked at 34 adults and found significant correlations between how sensitive someone was to these carbohydrates, their dietary energy and carbohydrate intake, and their waist measurements.
"Those who were most sensitive to the carbohydrate taste ate more of these foods and had a larger waist," Low said.
"We specifically looked at waist measurements as they are a good measure of the risk of dietary-related diseases."
Keast said this line of novel taste research was important because of the growing problem of dietary-related chronic illnesses.
"Increased energy intake — in particular, greater intakes of energy-dense foods — is thought to be one of the major contributors to the global rise of overweight and obesity, and carbohydrates represent a major source of energy in our diet," he said.
This research comes two years after Keast's team named fat the 'sixth taste'.
The fat taste studies explored the tongue's ability to detect fat as a distinct taste, similar to the ability to taste sweet, sour, bitter, salty and umami — the five traditional or classic tastes.
"Interestingly, what we found in the fat taste studies was that people who were more sensitive to fat consumed less fatty foods, but it's the other way around for carbohydrates," Keast said.
"What that could mean is that individuals who are more sensitive to the 'taste' of carbohydrates also have some form of subconscious accelerator that increases carbohydrate or starchy food consumption. But we need to do much more research to identify the reason why."