Are the grams on the supermarket products you buy accurate? Our snapshot investigation of 467 supermarket products found that some weighed significantly less…
In 2012 we discovered that 80% of the smoked salmon packs we’d measured were underweight. We wanted to broaden our test for 2015, so we asked food fraud expert Professor Chris Elliot to help us investigate underweight food in supermarkets.
His researchers at Queen’s University Belfast weighed 467 food products bought from supermarkets in Northern Ireland and found that 73 were below the recognised margin of error (this ranges from 4.5g on a product weighing 50g or 15g for a 1kg product).
Products that we found weighed less
Products weighing less than the margin of error:
- 23 out of 32 tins of Heinz Chunky Veg Big Soup.
- Six out of eight samples of Tesco Finest smoked salmon.
- 19 out of 31 Green Giant Niblets Original Sweetcorn contained less than the drained weight stated on packaging.
- Four out of 32 Del Monte Peach Slices in light syrup. Two were very underweight.

We’d expect a small variation in weight, which the margin of error accounts for, but we were surprised by how many samples were below this.
Enforcement for underweight foods
Trading standards officer Paul Ferris couldn’t comment on our research as it wasn’t carried out by accredited weights and measures professionals, but he did say:
‘Discrepancies may be due to natural desiccation of the product – as stated weight relates to the time of packing – inadequate staff training on packing, or incorrectly using weighing equipment.’
It’s important that manufacturers have effective checks in place to make sure you aren’t getting short-changed. And if products are found to be underweight, it’s important that Trading Standards continues its enforcement to help ensure compliance.
What do you think about underweight food? Are you sometimes suspicious that a product is lighter than it claims? Do you ever go to the lengths of getting the scales out to prove a point?