The ad ran online and was used to highlight changes made to Dairylea Lunchables, which cut the level of salt and saturated fats.
Three people complained about the "packed with good stuff" claim, because they believed the products were, in fact, high in salt and saturated fat and, therefore, that the ads misleadingly implied Dairylea Lunchables were healthier than they actually are.
Kraft Foods UK responded to the complaints with evidence showing that the product contains calcium, Vitamin D and fibre, and therefore that "packed with good stuff" was a substantiated statement of fact.
However, while the Advertising Standards Authority acknowledged Kraft's response, it still ruled that the ad breached clauses on truthfulness and substantiation.
In its ruling, the ASA said: "We nevertheless considered that the claim 'packed with good stuff' implied that Lunchables contained a high proportion of nutrients that were beneficial to health, when we understood that they contained high levels of saturated fat and sodium.
"We therefore concluded that the claim 'packed with good stuff' was misleading."
Kraft has already said the ad will not be running again. The company has been advised by the ASA to consult with the CAP Copy Advice team before running further ads.