Do consumers buy sustainable products? For years, brand managers have tried to understand why consumers say they intend to buy sustainable products, but when it comes to buying, they don't.

Coined as the attitude-behaviour gap, after several phases of investigations into consumer behaviour, from the theory of planned behaviour to the role of emotions in consumption, academia has somehow concluded to what the reason might be.

Nevertheless, so far, most brands have taken the attitude-behaviour gap as justification for not making their products more sustainable. 'They say they want them, but they don't buy.'

However, it looks like things have started to change. Either the brand managers have started to look into academic research and apply some of the findings, or, the consumers are finally getting what they were looking for.

A recent study into U.S. consumers done by the NYU Stern's Center for Sustainable Business on the actual purchasing of consumer packaged goods (CPG), combined with further data from the IRI - the biggest bar codes scanner company at retail checkout in food, drugs, and mass merchandisers - has shown that more than 50 per cent of CPG growth between 2013 and 2018 originated from sustainability-related products.

The NYU Stern's Center for Sustainable Business extensive study into U.S. consumers has looked into more than 71,000 SKUs and 36 product categories, which accounted for 40 per cent of CPG dollar sales over the five years.

We also reviewed which categories had the largest share of sustainability-marketed products. Toilet tissue, facial tissue, milk, yoghurt, coffee, salty snacks, and bottled juices were among those with the highest percentage in their category (more than 18%), while laundry care, floor cleaner, and chocolate candy had less than a 5 per cent share.

Some of the investigated categories saw tremendous growth in the demand for sustainability specific products such as sanitary napkins, laundry and other care marketed products, which were among the highest, at 150 per cent.

For corporate managers and investors, these findings mean that while consumers have begun voting with their dollars against unsustainable brands. There is compelling evidence that consumers' tastes are changing.

On the other hand, most brands have the attitude of "Why mess with the product now if it has worked so well over the last 50 years?", signalling the beginning of a new era. A conscious consumer era where new brands will emerge, and those failing or unwilling to adapt will perish.

Large giant companies that will thrive must accept this consumer shift towards sustainable values. Unilever is the best example of the necessary transformation and how it can be accomplished.