The CO2 Math Behind Every Meal You Save

When food ends up in a landfill instead of a plate, the problem is not just that it was wasted. It is that it keeps causing harm on the way out. Food waste does not sit quietly in the ground. It decomposes without oxygen and releases methane, a greenhouse gas that traps far more heat than CO2 does over the short term.

Multiple independent estimates, including figures tracing back to FAO research, put the full climate cost of wasted food at roughly 2.5 to 3.8 kilograms of CO2-equivalent emissions for every kilogram thrown away, once you count both the methane from decomposition and the energy, water, and transport that went into producing food that nobody ate. That range is not a marketing number. It shows up consistently across food-waste research, and it is the same math behind why Pakistan wasting millions of tonnes of food a year is a climate story, not only a hunger story.

Turning that into something one meal means

SastaKhana's in-app Impact tracker uses an estimate of about 1.35 kilograms of CO2 avoided for every meal rescued through the app. That figure sits inside the published research range above, scaled down to what a single meal's worth of food roughly represents, rather than a full kilogram of waste. We are treating it as a reasonable working estimate, not a precise laboratory measurement, and we will keep refining it as better data comes in.

The tracker itself lives in the app, not on this website, and it works simply: every time a meal gets picked up through SastaKhana instead of getting thrown out at closing time, that estimate gets added to your own running total, alongside a personal goal you can watch yourself get closer to.

Why this is not the same as the food-waste problem itself

Rescuing surplus food does not stop food from being over-produced in the first place. That is a separate, harder problem involving forecasting, portion planning, and how restaurants buy ingredients. What rescuing surplus food does is make sure that food which has already been made, and would otherwise be thrown out today, gets eaten instead of decomposing in a landfill. That is the entire mechanism behind what SastaKhana actually is, and it is also exactly where the CO2 savings come from.

Multiply one rescued meal's 1.35 kilograms across a whole community doing this regularly, and the number stops being trivial without anyone needing to change what they eat, only when and how they get it.