Why does waste happen?
Not only what is discarded, but which routines, expectations and constraints made that outcome likely.
Research
Food waste is never only about food.
I am a PhD candidate in Sustainability at the Universitat Politècnica de Catalunya, working with the Centre for Research in Agri-Food Economics and Development (CREDA–UPC–IRTA) to understand why food gets wasted—and which interventions genuinely change what happens in the real world.
The questions underneath
I look for the human decisions inside complex systems.
What changes behaviour?
Designing interventions with the people affected, then evaluating what changes beyond good intentions.
What survives reality?
Translating evidence into solutions that can work within homes, hospitals, hotels and supermarkets.
Selected work
From measurement to intervention.
Families · hotels · supermarkets
SPRINT
Stakeholder Prevention and Reduction of Inefficiencies in Food Management at the Consumer Level
Understanding the decisions and everyday systems that generate food waste, then co-designing and testing interventions in the places where it actually happens.
Co-designMixed methodsLongitudinal evaluation
Hospital food services
SWIFT-CARE
Sustainable Waste-Reduction Initiative for Food in Hospitals
Measuring food waste and listening across clinical, catering and patient perspectives to identify practical opportunities for prevention.
Direct weighingSystem dynamicsStakeholder research
Measurement · social, economic & environmental impact
Catalan Household Food Waste Quantification
Contributing to the 2024 diagnosis of household food waste in Catalonia: evidence designed to improve understanding and support public policy.
Objective measurementSurvey researchQuantitative analysis
Mediterranean families
SWITCHtoHEALTHY
Switching Mediterranean Consumers to Mediterranean Sustainable Healthy Dietary Patterns
Designing and implementing culturally sensitive, family-based interventions that encourage healthier and more sustainable Mediterranean dietary patterns.
Intervention designBehavioural researchSurvey research
Research philosophy
“Science is not about names, numbers, competition, or hierarchy, but about collaboration and respect for knowledge put at the service of doing things better.”— Tianyu Zhang-Jin
Research toolkit
Four ways into a messy reality.
Measurement & data
Direct weighing · Administrative, scanner and primary data
Behaviour & interventions
Behavioural modelling · Intervention design
Evaluation
Longitudinal and pre-post evaluation · PLS-SEM
People & organisations
Survey research · Mixed methods · Qualitative stakeholder research
Current manuscripts
Last updated · September 2026
Research in the publication process.
A multi-sector direct weighing protocol with diet-stratified sampling for hospital food waste quantification
Tianyu Zhang-Jin, Djamel Rahmani & José María Gil Roig
Under review · MethodsXAre Food Waste Policies Based on the Right Behaviour? Evidence from Objective Household Waste Measurement in Spain
Tianyu Zhang-Jin, Diego Vidal-Henríquez, Djamel Rahmani & José María Gil Roig
Under review · Food PolicyDiagnosing Retail Food Waste Using Administrative Data: Evidence from a Supermarket Intervention
Tianyu Zhang-Jin, Djamel Rahmani & José María Gil Roig
Accepted for publication · British Food Journal · Revisions in progressIntervention Feasibility Under Institutional Constraints: Why Food Waste Reduction in Luxury Hospitality Shifts from Consumer-Facing to Operational Solutions
Tianyu Zhang-Jin, Djamel Rahmani & José María Gil Roig
Under review · International Journal of Hospitality ManagementUnderstanding Hospital Food Waste Through System Dynamics: Evidence from a Full-System Direct Weighing Study
Tianyu Zhang-Jin, Djamel Rahmani & José María Gil Roig
Under review · Journal of Cleaner ProductionPublished work & reports
Work you can read now.
2025Diagnosi del malbaratament alimentari a les llars de Catalunya l’any 2024Research report · Generalitat de Catalunya2024Resum executiu 2021–2023 — Càtedra UPC–MercabarnaResearch report · Mercabarna2024Switching Mediterranean Consumers to Mediterranean Sustainable Healthy Dietary PatternsStudy protocol · Nutrients 16, 39382020Landfill Earth: A Global Perspective on the Waste ProblemMA thesis · Universitat de Barcelona