The grocery store is a busy place, full of signs and signals that we may or may not always notice. Picture yourself in your usual store: do your eyes get drawn to a “limited quantities” sign or a “buy now before it’s gone” promotion?
Do you ever toss an extra item into your cart because of it? The reality is, you probably didn’t need that extra item, and a week later, half of it has ended up in the garbage. This isn’t just poor planning; it reflects a psychological trigger that most of us don’t realize is shaping our behaviour — and retailers use it widely.
Food waste continues to be a massive global problem. A 2021 United Nations report found that about 60 per cent of global food waste comes from households. Public campaigns appropriately encourage people to plan better, shop more carefully, and use and freeze leftovers. These are effective strategies, but they don’t tell the whole story.
Our research highlights an additional layer: psychological forces in the marketplace can quietly shape how much we buy in the first place, which can ultimately lead to more waste.
Intuitively, we might expect that feeling short on resources would make people more careful, conserve what they have and waste less. And in some cases, that’s true: people with fewer financial resources do tend to waste less food.
But our research explores what happens when people feel they don’t have enough, or perceived scarcity, regardless of what is in their fridge or bank account. And that’s where the pattern shifts.
Perceived scarcity
(AP Photo/Terry Chea)
When people experience perceived scarcity, this activates an acquisition goal — a mental drive to secure more resources. When food is readily available, such as when stores are well stocked and people have purchasing power, perceived scarcity can push people to acquire more than they actually need. Think of the COVID-19 toilet paper rush, but with everyday groceries.
This mismatch between what people buy and what they actually consume leads to increased food waste. Although scarcity can drive us to buy more, our physiological needs (how much we need to eat) stay the same. This surplus often becomes food waste. When we encounter scarcity cues, they don’t just nudge us to buy more; they can push us to over-acquire, taking more than we need.
We conducted experiments and surveys to examine how this works.
At a breakfast buffet, we placed a poster advertising “limited spaces available!” for an unrelated activity. We found that this led people to waste more food compared to the previous morning.
We also conducted a study in our lab. Participants prompted to feel they had fewer resources than others took more snacks and left more uneaten than those who felt relatively better off. And we conducted two large-scale surveys, which showed the same pattern in real households: perceived scarcity predicted greater food waste.
Many things can trigger a sense of not having enough. Retail messaging, such as “while supplies last,” is one obvious example. However, it doesn’t stop there. News reports about rising costs or product shortages, the pressure of limited time while shopping and even social media — where we see others enjoying experiences we feel we lack — can all activate a scarcity mindset.
These cues create a subtle but powerful feeling of “not enough,” which drives us to acquire more, often without realizing it. In short, the environments we live in nudge us to feel perceived scarcity, leading us to over-purchase and, ultimately, waste more.
Perceived scarcity isn’t the only psychological factor driving food waste. People have a natural tendency to seek variety, which causes us to overestimate how many options we might want. We might buy more variety, but not consume it because we fall back on routines.
We show optimism bias, buying perishables (like ingredients for that healthy salad) with good intentions, but fail to use them. And we engage in temporal discounting — a tendency to prioritize the present over the future.
In practice, this means we tell ourselves “I’ll use this before it goes bad,” but later on, other, more immediate options (like takeout or making an easier meal) win out. As a result, food we fully intended to use gets pushed aside until it spoils.
Steps you can take
(Unsplash/Artem Beliaikin)
Taken together, all this suggests food waste isn’t simply a planning problem — it’s a behavioural one shaped by multiple psychological forces. Given this, what can people do to make better decisions and prevent food waste?
Recognize scarcity cues. Simply being aware of the effects of “limited time” or “while supplies last” messaging can reduce its influence.
Pause before purchase. Ask yourself: Do I have a specific plan for this item? When will I realistically use it?
Start small. Purchasing smaller quantities of groceries more frequently can reduce over-buying. If you’re at a buffet, keep in mind that you can always go back for seconds, rather than overloading your plate.
Think ahead. Mentally (or even in writing) assign foods to specific meals ahead of time.
While these small shifts can help households counteract the pull of scarcity-driven buying, they are only part of the solution. The broader context also matters. Scarcity cues are embedded in retail and media environments, shaping how we feel and the decisions we make.
Given that households are responsible for the majority of food waste, reducing it requires retailers and food businesses to do better planning. It requires designing environments and shaping habits that work with our psychology rather than against it.
