As many as 2,529 products have shrunk in size over the past five years, but are being sold for the same price, official figures show.
The Office for National Statistics (ONS) said it was not just chocolate bars that have been subject to so-called “shrinkflation”.
It said toilet rolls, coffee and fruit juice were also being sold in smaller packet sizes.
At the same time 614 products had got larger between 2012 and 2017.
The ONS said the phenomenon of shrinkflation had not had an impact on the overall inflation figures. However, in the category of sugar, jam, syrups chocolate and confectionery, the rate of inflation when adjusted for shrinking products was significantly higher.
Since 2012, the inflation rate for products such as chocolate was actually 1.22% higher, when the smaller size was taken into account.
What’s getting smaller?
Andrex toilet roll. Was: 240 sheets, now 221 – an 8% reduction
McVities Dark Chocolate Digestives. Was 332g, now 300g – a 9.6% reduction
Tropicana Orange and Raspberry. Was 1 litre, now 850ml – a 15% reduction
source: Which?/ ONS
Dozens of chocolate bars and sweets have already got smaller.
Packets of Maltesers have shrunk from 121g to 103g, a reduction of 15%. Makers Mars have said it was a way of helper consumers afford the product.
Toblerone has shrunk by 12%, with larger spaces between the triangular “mountains”.
The manufacturers, Mondelez – formerly Kraft – said they changed the shape “to keep the product affordable”. It said it was experiencing higher costs for “numerous” ingredients.
But the ONS has cast doubt on whether raw material costs are really rising.
The European import price of sugar has been falling since the middle of 2014, and reached a record low in March 2017, the ONS said.
The price of cocoa, another major ingredient, reached a five-year high in December 2015, but has fallen sharply over the last year.
The ONS also dismissed Brexit as a reason for recent shrinkflation, even though it has contributed to an increase in the price of some imported goods.
“Our analysis doesn’t show a noticeable change following the referendum that would point to a Brexit effect,” the ONS said.