In a survey of 1,050 people, TNS Omnibus found the proportion of 'grazers' was even higher among the youngest consumers, with 33% of shoppers aged 16 to 24 admitting eating products in shops.
In Scotland, the overall figure rose to 28%, while north east England had the lowest proportion of shoppers who ate before they bought a product, at just 14%.
When pressed about the ethics of eating unpaid for food, just under half (47%) of those who admitted doing it agreed it amounted to theft.
Views about the acceptability of presenting an empty packet at the checkout were divided, with 52% thinking it was fine and 48% thinking it was wrong. Generally the proportion of those who thought it was unacceptable rose with age, although the strongest proponents of the practise were in the 25 to 34 age group, with the youngest consumer group, aged 16 to 24, finding it slightly less acceptable.
The oldest age group surveyed (55 to 64 year-olds) were the most disapproving, with 57% considering it unacceptable.
TNS Omnibus also asked the consumers about touching fresh produce in supermarkets. Touching fruit and vegetables before buying was considered acceptable by 78% of those questioned, but handling unwrapped fresh bread was generally frowned upon, with 81% considering it unacceptable. These beliefs were fairly consistent across all ages, classes and parts of the country.