Fat should be listed with sweet, sour, salty, bitter and umami as a taste, according to new research, and could be replicated to combat obesity.
Scientists claim that if they could create fat replacements to stimulate the same taste buds, low-calorie foods could be more appealing. They suggested that the unique — and unpleasant — taste should be called “oleogustus”.
Richard Mattes, director of the Ingestive Behaviour Research Center at Purdue University in Indiana, said: “Identifying the taste of fat has a range of important health implications.
“At high concentrations, the signal it generates would dissuade the eating of rancid foods. But at low levels, it may enhance the appeal of some foods by adding to the overall sensory profile, in the same way that bitterness alone is unpleasant but at appropriate levels adds to the appeal of wine and chocolate.”
He explained that existing fat replacements mimicked fat’s texture but not its taste, possibly making them less attractive.
About a quarter of the UK’s population is obese, costing the NHS about £6 billion a year. Fatty foods have also been implicated in heart problems.
The new study, reported in the journal Chemical Senses, used volunteers wearing nose clips to investigate the taste sensation of free fatty acids, the building blocks of fat. Volunteers were asked to sample a range of taste qualities and sort them into groups. The scientists manipulated the textures of the samples so that taste was the only difference. The participants identified fat as having a unique taste.
“Many people described it as bitter or irritating and consistently unpalatable,” Professor Mattes said. “The research is difficult because we do not have a widely agreed-upon word to describe the sensation.”
While sweet, sour, salty and bitter have been universally recognised for centuries umami, a Japanese term loosely translated as “savouriness”, has only been accepted more recently.
A paper in the journal Flavour also suggested this year that fat could join the list. The writers found that people who could not taste fat in food ate significantly more at lunch after a high-fat breakfast than those who could.
Russell Keast, the lead author of the paper, said: “It is becoming clear that our ability to taste fat is a factor in the development of obesity. We know that people have a taste threshold for fat. Some people have a high sensitivity to the taste and are likely to eat less fatty foods, while others are less sensitive and cannot taste fat and are more likely to overeat fatty foods. And as we know, over-consumption of foods — particularly fatty foods — is associated with people being overweight or obese.”
He suggested that increasing fat taste sensitivity in those who were insensitive could be “one way to address the growing obesity problem”.