Restaurants and fast-food outlets can fool the customer with thin-cut French fries, research at the Robert Gordon University has revealed.
Thinner chips make for a bigger portion in the mind of the eater, according to dietician Sarai Youngson, who has completed an honours BSc in nutrition and dietetics.
She showed 80 adults photographs of plates of fish and chips, using different portion sizes of chips that were straight cut, crinkle cut, thin and thick cut.
They were then asked to assess the portion sizes, and thought there were more of the thin-cut chips at all the different portion weights.
"This was significantly different to their perceptions for all other chip shapes for weights less than 200g," Ms Youngson said. She presented her findings to the Nutrition Society's annual conference held in London next week.
Ms Youngson's supervisor, Alan Wise of the school of food and consumer studies, has warned that thin-cut chips have more fat per 100 grammes and people may therefore be eating more fat, even if they eat a smaller portion of chips in the belief that it is bigger than it is.