The speed with which Mars has reversed its decision to switch to non-vegetarian whey in the production of some of its chocolate bars demonstrates the power consumer campaigns can exert on food producers, writes Ben Cooper. And although Mars wants to put the episode behind it, its swift response has been commended by vegetarian campaigners.

The increasing influence consumers and pressure groups can bring to bear on food companies has once again been illustrated, as Mars has been forced to abandon attempts to replace vegetarian-friendly whey in some of its chocolate bars and ice creams with whey containing the animal extract rennet.

Having received over 6,000 complaints, and seen 40 MPs sign a motion against the move, Mars UK conceded that it had become clear "very quickly that we had made a mistake", and on Sunday (20 May) announced a volte-face. "We have listened to their views and have decided to reverse our decision," said managing director Fiona Dawson. "All those people who have enjoyed our products in the past will soon be able to enjoy them once again."

"It's great that they have listened and shows the power of the consumer," Annette Pinner, chief executive of The Vegetarian Society, told just-food today (21 May). "They have responded to the concerns of vegetarians and full credit to them as long as they follow through with it."

Mars not only seems to have underestimated the extent of public opinion but may also have miscalculated the effect the move might have had on sales.

The estimated number of vegetarians in the UK is generally put at around 3m, and it would be widely thought that only a small percentage would be strict enough not to consume rennet, which is, for example, also used in the production of cheese.

However, The Vegetarian Society puts the total number of vegetarians and part-time vegetarians at 5.4m, and reckons that around 1.2m people would not consume a product containing rennet. In addition, products containing rennet are not kosher and not Halal. When those consumers are included in the equation, the numbers begin to mount up significantly.

Furthermore, Pinner suggested that non-vegetarian consumers may react with suspicion when told that meat by-products are used in foods where they might not expect to find them. In view of that, the highly public discussion of Mars products containing an ingredient made from the stomach linings of calves might not have the most favourable impact on sales. And, as Pinner also pointed out, the confectionery market does have a wide range of vegetarian-friendly alternatives to choose from.

Part of the Mars media strategy has been to say little about its U-turn, and it is unlikely that it would be forthcoming about the forecasting on which it based its original decision. But could it be that the company took the view that it would only lose sales among a small percentage of a minority, who were probably not prime target consumers anyway?

Was the company even guilty of stereotyping those potential lost vegetarian consumers, imagining that they would probably prefer a carob slice or vegan flapjack over a Mars Bar in any case? In the current climate, one would not expect a chocolate bar producer to characterise a consumer group as 'too health-conscious' to be prime consumers of its products, but this could be one interpretation of its actions, albeit a somewhat contentious one.

Pinner was happy to point out that, while probably more aware of dietary issues than average consumers, vegetarians are just as likely to want to indulge themselves. "Most vegetarians not puritanical," she said. "They will enjoy a Mars Bar as an occasional treat just like anyone else who has reasonable eating habits."

The speed with which Mars has conceded on this matter seems to imply that the benefit the company hoped to gain from the switch was not all that significant, and certainly not enough to outweigh the negative impact. Mars said last week that it was making the change "to ensure the quality and availability of the supply of whey" which probably means there was a commercial benefit too. Easier to source would generally mean less expensive. One would imagine that if those commercial benefits were sizeable, the company might have held out a little longer.

What the episode clearly demonstrates is just how quickly consumer campaigns against branded companies can gather pace. In an era of mass communication, where such public interest stories are often viewed as juicy subjects by journalists across all media, particularly if the brands concerned are household names, large corporations have to pick their fights.

That said, even though Mars has opted to say little about its change of heart, Pinner for one believes the company has done its public credibility no harm at all by reversing its decision so swiftly, and being seen to have listened to consumer opinion.

Moreover, talks are continuing between Mars and The Vegetarian Society about vegetarian-friendly labelling and possible accreditation for the company's products.

Confectionery products, that is. The vegetarian campaigners may have won a notable victory, but hoping to persuade Mars to take a similar course of action in its pet-food division may be a tad optimistic.