Sustainability
A family-size pack is not a saving if half gets thrown away
By Prof. Alessandro Buffoli, PhD
The shelf gives a price per gram purchased. The household pays for the amount it actually uses.
Two packs sit side by side. The small one contains 350 grams and costs HK$30. The large one contains 700 grams and costs HK$50. The large pack is better value per gram bought.
Now suppose a household uses only 350 grams from either pack and discards the rest of the large one. Under that hypothetical behaviour, the small pack costs about HK$8.57 per 100 grams eaten. The large one costs about HK$14.29. The shelf comparison has not become mathematically wrong. It is answering a different question from the household’s eventual cost.
Of course, a household that uses all 700 grams gets a different result. So does one that can safely store the remainder for a later meal. That variation is precisely why I dislike treating the largest size as an automatic recommendation.
Sell a realistic amount of use
For perishable food, I would investigate how the pack fits actual meals. How many people use it? How often? What quantity does a common recipe require? Does the buyer know what to do with the remainder?
Those questions can suggest a useful pack change or a credible serving idea. They can also reveal that the large format works well for one household and poorly for another. The business does not need to declare one size morally superior to acknowledge that difference.
A multi-compartment pack might help some products. It might also introduce extra material or cost. Storage guidance could help, but it must match the food and its real handling requirements. The proposed solution needs its own assessment rather than an assumption that one extra instruction fixes waste.
Measure what the promotion brings forward
The same reasoning applies to multi-buy offers. Selling two packs this week may replace a sale next week. If the second pack is discarded, the promotional volume is even less informative about useful consumption.
I would compare households offered different formats or promotions over a period long enough to observe their use. Record spending, repeat purchase, the amount consumed and the amount discarded. A retailer trying to improve sustainability needs more than a bigger checkout total.
There is a commercial argument for helping customers choose a quantity that works. Disappointment with wasted food can become disappointment with the purchase. That relationship is worth testing rather than assuming that the lowest unit price wins loyalty.
For me, the practical copy question is simple: can the customer judge whether this pack fits their week? A legible unit price remains useful. A clear quantity, realistic serving information and an appropriate choice of sizes can make it much more useful.
Prof. Alessandro Buffoli, PhD
Assistant Professor of Marketing at The Hang Seng University of Hong Kong.