Such research appears to vindicate recent decisions to ban fizzy drinks and junk food from schools in the UK under the Education Bill, and in schools and colleges around the US, amid growing concerns for the escalating rise in obesity, particularly amongst the young.
Over 14 million Europeans are obese or overweight, of which more than 3 million are children.
Obesity-related illnesses, which include heart disease and diabetes, account for up to 7 per cent of healthcare costs in the Union. In some Member States, over a quarter of the adult population is now obese.
"A potential factor contributing to the rising prevalence of obesity is greater dietary variety, particularly from highly palatable, energy-dense foods, leading to increased energy intake," said researchers Hollie Raynor and Rena Wing from Brown University Medical School.
The new study, published recently in the journal Appetite (Vol. 46, pp. 167-176), recruited 21 non-obese, dietarily unrestrained men (average age 20) and randomly assigned them to one of two conditions: the Same Snack condition (to consume the same snack during lab sessions and at home), or the Variety condition (to consume a range of sweet and salty snacks during lab sessions and at home).
Raynor and Wing report that the pleasure associated with eating the same snack (crumb cake) decreased by about 12 per cent, while the pleasure of eating the cake increased by about five per cent in the group allowed to eat a variety of snacks, after four days.
Consumption of the same snack for four days also led to a decrease in consumption, and therefore less energy intake.
"This current study is the only investigation that has examined long-term sensory-specific satiety and monotony under controlled exposure situations," said the scientists.
The researchers called for more research to identify factors that may reduce 'liking' and 'wanting' of foods and thereby reducing consumption.
"Once factors are identified," said Raynor and Wing, "they can be incorporated into interventions that focus on reducing energy intake (e.g. weight loss interventions), aiding in increased adherence to dietary prescriptions that recommend decreasing overall intake or intake of specific problematic foods."
The authors did note limitations with their study, namely the small sample size, and the focus on non-obese, dietarily unrestrained young men.
"To increase the generalisability of the outcomes of this study, future investigations should examine the effect of limiting across day variety in snack foods in other populations, such as females, restrained eaters, obese individuals, and individuals with eating disorders," they said.
Such results may be welcomed by campaigners against the presence of vending machines offering children and adolescents a range of snack foods and fizzy drinks, seen by many as a key factor in the rise of obesity.
For its part, the European Vending Association (EVA) said in April that the vending industry should stop being used as a scapegoat if answers to the obesity crisis are to be found.
In addition, EVA questioned the scientific data regarding the excessive intake of energy-dense snacks and sugar-sweetened soft drinks. The association called for an evaluation to be put in place to assess the link between obesity and the intake of energy-dense snacks and sugar-sweetened soft drinks.
"The notion of 'excessive intake' is vague and very subjective, and it is unclear how it impacts directly on the BMI (Body Mass Index), and we know it cannot be the only factor. The other side of the equation (energy out) very much determines if the intake is excessive or not. Finally, we support the view that there is no such thing as a good or bad food, it all is a matter of appropriate quantities, said the association.