1) Separate

The first step consists of correctly separating food waste into 4 different containers:

PACKAGING, where we put possible inorganic remains, such as food containers, yoghurt containers, the containers of water and other liquids, or disposable containers used to carry cooked food.

INEDIBLES, where we put the organic remains that aren’t eaten, such as fruit peels, fish bones, paper napkins, etc.

EDIBLES, where we put the remains of food that could have been eaten, except for water.

WATER, in the last container, we put the leftover water that can’t be taken advantage of.

2) Weigh

The second step systematically establishes an exact weight of the waste generated and the relationship between it and the result of the number of meals served. It’s very important to write down the exact amounts.

To systematically manage the data collected separately each day, writing down the following: the name of the school; the town/city; the date the data was collected, the menu served, the number of meals served, the kg of packaging; the kg of inedible items; the kg of edible items and the litres of water.

Then the sum of the last 30 days of kg generated by all of the school children will be calculated using the formula:

kg of ... from day 1 + kg of ... from day 2 + ...

As well as the kg wasted per meal, using the formula:

Monthly sum / number of meals


Children who participate in the Weigh and Think iniciatives are those who best explain the origin of the project. Take a look at the video!

3) Record

The next step will consist of providing the school children with a tool to record the data collected and then analyse it

4) Think

The most important part of the method. Once the data is recorded, the school children, the cooks, and the monitors analyse the data collected regarding the waste produced.

With the THINK step, we become aware of what we eat, the role that it plays in our diet... for the purpose of developing a critical attitude towards consumption and for everyone (children, cooking staff, and monitors) to jointly develop strategies to reduce waste production and food waste.

During the first month of implementation, it is recommended that only steps 1 to 4 be done.

5) Set a goal

On a monthly basis, we propose creating a system for gathering all of the data and defining quantitative goals to achieve for the following month.

It’s recommendable to develop the SET A GOAL step once the first month has passed, not before. In this manner, we manage to generate some initial data for diagnosis.

We understand this step as something that can be revised month by month, adapting the goals to be set to each group of children’s possibilities. This should become a motivating tool for them where the goals reached are reflected.