Research by Brian Wansink, a professor of marketing and nutritional science at the University of Illinois at Urbana-Champaign and co-author Barbara E. Kahn, challenge the notion that a person's ability to control eating is related to willpower. They conclude that it is not just variety, but the perception of variety, that stimulates how much a person consumes.
The researchers claim that consumers need to become more aware of how colour, package size, variety and physical proximity influence the amount of food they ingest.
In an article in a recent issue of the Journal of Consumer Research the Wansink claims that the context can lead people to overindulge and unknowingly 'bulk up.'
"People eat with their eyes, and their eyes trick their stomachs," Wansink said. "If we think there's more variety in a sweet dish or on a buffet table, we will eat more. The more colours we see, the more we eat."
For example, adults offered six colored flavours of jellybeans mixed together in the same bowl ate 69 per cent more than when the colours were each placed in separate bowls.
In another study, cinema goers given M&M sweets in 10 colours ate 43 per cent more than those offered the same number of M&Ms in seven colours.
An earlier study by Wansink found that cinema-goers given an extra-large bucket of popcorn will eat up to 50 per cent more than those given a container one size smaller - even when the popcorn is stale.
"Many of us are reasonably diligent about what we eat, but we don't put that much thought into how much we eat," Wansink said. "People may decide to eat grapes instead of potato chips because it's healthier. Once they make that initial choice, they tend not to monitor how much they eat. And a pound of grapes is not calorie-free."