This is happening in every country, and I have a feeling it's not only packet size. It's also what they feed the animals. I don't know what they feed the chicken, but year 2000 chicken tastes completely different than nowadays chicken and it take longer to fry.

Crolic, an associate professor at University of Oxford's Saïd Business School, who focuses on consumer behaviour, agrees. Because consumers are so focused on how their purchases are affecting their wallets, she says, they are "more likely to notice the increase in price than the amount of product 'lost' when packages shrink".

Consumers do not always see the changes right away; often, they are incremental. For instance, a favourite drink that may have come in a 12oz (340g) bottle a year earlier may now be offered for the same price, yet downsized to 10oz (283g) now.

And experts say that once the new sizes are on the shelf, they are likely to stay that way. Phil Lempert, food industry analyst and editor of SupermarketGuru adds that, since shoppers don't have a choice, they have to adapt to the changes.

In some cases, they can switch to products with better value – US-based Lempert says brand loyalty plummets amid shrinkflation, with people often transitioning to house brands. But with essentials, consumers may not have as much choice. For instance, if you depend on baby formula, and a store only stocks one option, you're stuck paying the price on the sticker, and getting whatever is in the tin; at Carrefour, Nestlé's Guigoz infant milk formula had gone from a pack size of 900g to 830g (31.7oz to 29oz), for example.

Yet even as shrinkflation largely corresponds with inflation, Crolic says consumers usually don't see product sizes rebound even after economic challenges abate. There are rare exceptions, but companies generally seize the opportunity to use less product and make the same amount – or more.