Our research examines how the demographics and environmental attitudes of retail customers influence their purchasing behaviour of niche and mainstream sustainable products and whether this influence varies by products. We employ actual supermarket sales data from over 300 outlets in England covering 18 million customers, and examine two products that can both be labelled as sustainable but have very different market positions: organic milk as a typical niche product, and free range eggs which (based on market share) can be seen as a mainstream product. Our results partially confirm previous research – which is typically based on self-reported behaviour – identifying both price and deprived catchment areas as barriers but green attitudes as a driver of sustainable purchasing behaviour. Yet, the results clearly indicate that not all sustainable products are considered the same by consumers, and that consumption behaviour varies considerably across sustainable product categories. For organic milk as a niche product, we find more affluent people more likely to be purchasers. What is new is that we also see older families and those aged 25-44 as purchasers. White and Asian ethic origin are a negative influence. On the other hand, consumption of free range eggs – as a mainstream product – does not seem to be influenced much either by attitudes or by demographics. Comparing our two different products, the impact of socio-demographic factors in particular on purchasing behaviour therefore appears to be fading with increasing market penetration. Our results may provide important cues for the ongoing debate on the need to mainstream sustainable consumption. The fact that we observed very different underlying dynamics between niche and mainstream sustainable products raises questions about the current positioning of sustainable (niche) products more generally. Further research needs to be done around the marketing methods retailers have employed for sustainable labelled products. Are they using methods that just appeal to niche green consumers who may not be buying their products from a mainstream retailer anyway? Are these marketing methods putting off mainstream consumers who may buy organic milk but need better marketing that appeals to their mainstream consumer values? This is key as mainstream consumers are used to buying sustainable labelled products but retailers need to change their marketing of these products to mainstream consumers.
