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How to reduce food waste

Food: why do consumers waste food?

Marina Julienne, Independent Journalist
On May 11th, 2022 |
3 min reading time
Sandrine Costa
Sandrine Costa
Economist and Research Fellow at the MoISA* laboratory of INRAE
Key takeaways
  • Sandrine Costa studies food waste to suggest measures that can impact on consumer behaviour.
  • By studying the leftovers on trays of 479 people who had eaten in different company restaurants, she observed that while 398 of them had left food, only half of them said they had.
  • Collective catering is a strategic lever in the fight against waste. It has been estimated in various European countries that between 13 and 55% of the food produced and distributed in collective catering ends up in the bin.
  • Making a shopping list, learning how to cook leftovers, reserving a specific place in the fridge for leftovers so that each member of the family can spot them, can all be effective in avoiding waste.

Why have you directed, or co-directed, so many theses on food waste?

To pro­pose mea­sures that can have an impact on con­sumer behav­iour. If we hope to reduce food waste, it is essen­tial to under­stand why peo­ple waste in the first place. Are con­sumers aware or not that they are throw­ing away food? Does it make them feel uncom­fort­able or not? What are the indi­vid­ual, but also social or mate­r­i­al fac­tors that influ­ence their behav­iour? These stud­ies take a long time to car­ry out, as they involve going to cater­ing facil­i­ties or can­teens, and into fam­i­lies to observe what hap­pens there or to con­duct indi­vid­ual inter­views. We can­not always be sat­is­fied with declar­a­tive state­ments in response to ques­tion­naires. Not least because peo­ple tend to down­play waste­ful behaviour.

Doesn’t everyone have the same definition of waste?

Indeed, Maxime Seb­bane, a lec­tur­er in mar­ket­ing at the Insti­tut Agro Mont­pel­li­er, has worked on col­lec­tive cater­ing and has shown to what extent the def­i­n­i­tion of waste is not self-evi­dent. It depends in par­tic­u­lar on the quan­ti­ty left (some peo­ple con­sid­er that leav­ing half a piece of bread is not waste­ful, where­as oth­ers will con­sid­er it to be), the qual­i­ty of the prod­uct left (a bad­ly cooked veg­etable will be con­sid­ered waste­ful or not) and even, more sur­pris­ing­ly, the nature of the prod­uct: for exam­ple, a per­son who leaves a dessert behind may con­sid­er that it is not waste­ful because it is bet­ter for his or her health not to eat too much sugar! 

Fur­ther­more, we found that many peo­ple deny their own waste habits. When we stud­ied the left­overs on the trays of 479 peo­ple who had eat­en in dif­fer­ent com­pa­ny restau­rants, we found that while 398 peo­ple had left food, only half of them said they had left any! 

Wasteful behaviour is not only dependent on individuals?

In the frame­work of a qual­i­ta­tive research study con­duct­ed with Mar­got Dyen, lec­tur­er in mar­ket­ing at the Uni­ver­si­ty of Savoie Mont-Blanc and Lucie Sirieix, pro­fes­sor in mar­ket­ing at the Agro Insti­tute of Mont­pel­li­er, we were inter­est­ed in what peo­ple do and say around the “Eat Smart” cam­paign and the “Anti-waste” cam­paign. Mar­got Dyen con­duct­ed inter­views and then went to the homes of the peo­ple inter­viewed to observe their prac­tices in their social and phys­i­cal envi­ron­ment. Many of these prac­tices are based on com­plex coop­er­a­tion and coor­di­na­tion between dif­fer­ent peo­ple in the house­hold. When you must man­age the food pref­er­ences of sev­er­al peo­ple, the sched­ules of adults, chil­dren and teenagers who do not eat at the same times, it is very com­pli­cat­ed to avoid waste. For exam­ple, veg­eta­bles bought to meet the “good nutri­tion” plan can end up in the bin…

What recommendations can be drawn from these studies?

In the cater­ing indus­try, our research has shown that an organ­i­sa­tion can clear­ly induce waste­ful behav­iour and/or fos­ter a sense of ‘enti­tle­ment’ to waste. For exam­ple, charg­ing a sin­gle price for a ‘starter-main’ or ‘course-dessert’ com­po­nent does not encour­age din­ers to mod­u­late their choic­es accord­ing to their appetite, and a sin­gle size of con­tain­er does not encour­age them to mod­u­late quan­ti­ties accord­ing to their appetite either.

We con­duct­ed an exper­i­ment with more than 200 par­tic­i­pants by offer­ing con­sumers “small hunger” plates (21 cm in diam­e­ter) or “large hunger” plates (24 cm in diam­e­ter) for the main course, which allowed peo­ple to ask for a quan­ti­ty adapt­ed to their appetite, and for cooks to serve small­er quan­ti­ties. This mea­sure, which is very sim­ple to imple­ment, reduced the amount wast­ed by 20%.

It should be remem­bered that col­lec­tive cater­ing is a strate­gic lever in the fight against waste. It has been esti­mat­ed in var­i­ous Euro­pean coun­tries that between 13 and 55% of the food pro­duced and dis­trib­uted in col­lec­tive cater­ing ends up in the bin. In France, this sec­tor rep­re­sents near­ly 3.6 bil­lion meals per year, which gen­er­ate 440,000 tonnes of waste – this rep­re­sents an eco­nom­ic loss of €910 mil­lion per year and 1.5 mil­lion tonnes of avoid­able green­house gases!

What can be done to reduce waste at home?

Mak­ing a shop­ping list, learn­ing how to cook left­overs, reserv­ing a spe­cif­ic place in the fridge for left­overs so that each mem­ber of the fam­i­ly can find them, can all be effec­tive. More gen­er­al­ly, the research we con­duct­ed with Guil­laume Le Borgne, a senior lec­tur­er in mar­ket­ing at the Uni­ver­si­ty of Savoie Mont-Blanc, showed that indi­vid­ual aware­ness of waste had a more marked pos­i­tive effect on the adop­tion of “anti-waste” prac­tices than “glob­al” aware­ness. Clear­ly, com­mu­ni­ca­tion cam­paigns that high­light the sav­ings that can be made by the house­hold by wast­ing less will be more effec­tive than cam­paigns that point out the neg­a­tive effects of waste on the envi­ron­ment and waste man­age­ment. Final­ly, peo­ple who are made aware of “waste” from child­hood will waste much less than oth­ers, which argues for edu­ca­tion on this sub­ject from school onwards.

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