Soda sales fell in the Berkeley stores that complied with its checkout display ban

The sample is 71 stores in four cities, about eighteen per city on average ^[4][24]. Sales arrive as quarterly volumes from March 2019 through December 2023, which is 58 months, and only the last 24 of those follow the enforcement date of January 1, 2022 ^[5][25][2]. The comparison cities are Davis, Oakland and Sacramento ^[4]. A design like that can subtract a California-wide trend in soda buying from Berkeley's numbers, but not whatever else began in Berkeley alone in 2021.

Earlier work by Jennifer Falbe, the senior author, found that the added sugar in checkout foods and beverages fell 70% in the first year after the ordinance took effect ^[13][18]. Ten of those twelve months came before the rule was enforceable ^[27]. Retailers rearranged the racks well ahead of any penalty, and the purchase data moved later.

"Our findings suggest that healthy checkout policies can help reduce impulsive purchases and even encourage healthier snack choices, but it is critical for cities to actively enforce these policies if they aim to see meaningful and sustained decreases in sugary product sales," said Justin White, a co-lead author and associate professor of health law, policy and management at Boston University School of Public Health ^[15][17].

Total candy sales rose after implementation, and snack-sized nuts and seeds rose too ^[8][9]. Two categories moving the same way, one targeted and one not, suggests overall snack buying went up in those quarters. The test specific to the checkout lane is package size. That is why the team broke candy and soda out by pack: snack-sized items are the ones typically stocked at the register ^[28].

These data cover sales, not consumption. Scanner records show what left the register in those 71 stores ^[4]. They cannot see a Berkeley resident buying the same bag in an adjacent city, and they cannot separate a shopper who skipped the purchase from one who walked to the candy aisle and made it there.

The public summary gives directions and significance labels: soda down substantially, supermarket small packages down significantly, total candy up moderately ^[6][7][8]. It attaches no percentage change to either category ^[26]. The one percentage in it belongs to the earlier checkout-audit study, the 70% cut in added sugar on the racks ^[13].

Other US cities and other countries are considering and beginning to implement similar checkout rules ^[23]. Per the CDC, 6 in 10 youth drink a sugar-sweetened beverage on a given day ^[20].