Fans of I Can’t Believe It’s Not Butter, Bertolli and Flora have been warned the tubs are shrinking but staying the same price.
Food giant Upfield makes Flora, Bertolli and I Can’t Believe It’s Not Butter , and has cut sizes of these tubs from 500g to 450g.
But prices for the three spreads have stayed the same.
The move is an example of 'shrinkflation' - where a product shrinks in size but costs the same.
Upfield makes each of the three spreads.
A spokeswoman for Upfield told The Grocer : "We are seeing significant commodity cost increases, including our raw ingredients. This has impacted our supply and has increased our manufacturing costs.
"To continue providing consumers with affordable and quality products we have had to reduce the amount of spread in our 500g tubs to 450g to ensure a reasonable price point and have clearly stated this on pack."
The news comes as annoyed shoppers slammed rising butter prices, as the cost of a single tub of Lurpak now costs £7.25 in some supermarkets.
Lurpak owner Arla Foods said butter, cheese and milk prices could rise even further due to a shortage of workers.
Households will see their yearly food shopping bills hiked by £380 this year due to the soaring price of groceries.
Now Arla, which owns Lurpak butter and Cravendale milk, said prices are set to rise more due to problems filling vacancies in the dairy industry.
The dairy giant said 80% of farmers looking for workers have had 'very few' or 'zero' decent applications this year.
Farmers also face paying higher costs of animal food, fertiliser and fuel, meaning dairy prices must rise.
Households are continuing to be hit by high energy and fuel prices, new data shows, but the costs of other products, like pizza and quiche, rose more rapidly between April and May.
Potatoes had previously avoided some of the high inflation figures that other food items saw in recent months, however, in May they started catching up as the rate of inflation for potatoes more than doubled to 5.1%.
Shoppers are also increasingly swapping branded items for cheaper own-label products as they look to manage their budgets.
Asda’s chairman has said that some customers are setting £30 limits as they cut back on spending amid the cost of living crisis.
Lord Stuart Rose said customers are putting fewer items in their baskets and choosing from budget ranges more often as they try to mitigate price increases.
Sales of branded products fell by 1% in the 12 weeks to June 12, while own-label sales rose by 2.9% and value own-label lines surged by 12%.
Grocery analysts this month warned that supermarket costs could rise by 15% this summer and leave shoppers skipping meals.
The Institute of Grocery Distribution (IGD) said households are set to pay more for essentials including dairy, bread and meat as inflation is predicted to hit 11%.
It means the typical family of four could see their shopping bill rise as much as £40 per month, it warned.
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