FAQs

Land area used per year. In your results, the used land area isn't necessarily land that has been newly cleared (although it might be, think Amazon Rainforest) and it doesn't mean the land can't be used again (although something like that could be true, think Dust Bowl). If your land results show a positive number, this means your diet requires more land to be placed into production than the average diet. Conversely, a negative number requires less land than the average diet.

See the Diet Type Breakdowns Table to view a breakdown of the default food product proportions for each diet type. Note, information on blood sucking and insectivor-ish humans is limited, so each of these two categories is currently 0.0%.

See the Food Category Breakdowns Table to view a breakdown of the main food items that makeup each food category. Some food items fit into multiple categories but we've chosen what we consider to be the most appropriate fit for our purposes. For example, a tomato is commonly considered a vegetable but is technically a fruit. We've chosen to place it in the vegetable category.
You might be unfamiliar with some of the food category names. For explanations, you can search through the Terminology section of these FAQs.

The water data represents the rain and irrigation water used in the agricultural stage of production (for example, for growing crops, for animals to drink), which is the most consumptive stage in a product's life. The GHG and land data we use start with agriculture (land use change, if any) and end at retail purchase (no consumer cooking).

Both, rainwater and irrigation water are included in our estimates. We think this allows for a more region independent picture of a food product's water footprint, as opposed to just including irrigation water. Focusing on irrigation water has its benefits though, such as, giving a sense of the stress applied by a food product on the water supply. But if a crop relies very little on irrigation because it is being grown in a wet climate, then it might give a false sense of how much irrigation water that crop would require if grown in a dry climate. This is one reason why we've chosen to include rainwater in our estimates.

Our water data mostly* comes from:
Mekonnen, M.M. and Hoekstra, A.Y. (2010) The green, blue and grey water footprint of crops and derived crop products, Value of Water Research Report Series No. 47, UNESCO-IHE, Delft, the Netherlands.
https://research.utwente.nl/en/publications/the-green-blue-and-grey-water-footprint-of-crops-and-derived-crop-3
and
Mekonnen, M.M. and Hoekstra, A.Y. (2010) The green, blue and grey water footprint of farm animals and animal products, Value of Water Research Report Series No. 48, UNESCO-IHE, Delft, the Netherlands.
https://research.utwente.nl/en/publications/the-green-blue-and-grey-water-footprint-of-animals-and-animal-pro
* Seafood data comes from Poore and Nemecek. See below.

Our greenhouse gas and land data come from:
Poore, J., & Nemecek, T. (2018). Reducing food's environmental impacts through producers and consumers. Science, 360(6392), 987–992. https://doi.org/10.1126/science.aaq0216
https://science.sciencemag.org/content/360/6392/987
In-turn, this study utilizes data from 570 other studies published between 2000 and 2016; covering ~38,700 farms, 119 countries, and products that together represent ~90% of protein and calorie intake.

One reason is farmed seafood, which might use crop land for feed and human-made ponds for habitat, for example. Another is water used during processing (for example, cleaning of fish and equipment). The data we use factors in GHGs emitted during production, not just by the products themselves, but also by, for example, the machinery used.

Some reasons are:

• Burning of forests to clear land for crops, and thus the release of stored carbon in the trees and soil.
• Machinery used in the production process.
• Transportation of products from the farm to the market.

Meal plan estimations take into account your individual meals (Meal Estimator), meal plan meals (Meal Plan Estimator, of course), and general diet info (General Estimator), in that order of priority.

Starting with the Sunday Breakfast meal slot, first we check whether you've completed any individual meal estimates for Sunday Breakfast this week. If there are more than one of those meal estimates for this week, then we take the most recent, and move on to the next meal slot. If no individual Sunday Breakfast meal estimates have been completed this week, then we check to see if you have any Sunday Breakfast meals currently saved in your meal plan. If so, we take the most recent meal and move on to the next meal slot. If no meal is saved in your Sunday Breakfast meal plan slot, then we create an average breakfast for you based on your most recent general estimate, and move on to the next meal slot. This is why you must complete a general estimate before you can execute a meal plan estimate.

You can think of it as a buffet meal. The average meal we use isn't a meal you'd typically eat. Wait, what? Isn't typical kind of like the definition of average? We're defining it as an average of the resources. So back to thinking of it like a buffet meal. At a buffet you might grab a large variety of items/products/ingredients compared to a meal you might cook at home, where you might only use soy one night and only chicken the next night as your protein source. Your buffet meal on the other hand, might consist of a little bit of soy, a little bit of chicken, a little bit of lentils, a little bit of pork, a little bit of milk, etc. The average meal we use is kind of like that, in that it consists of a little bit of a lot of stuff. Another way of looking at it is that it's what the average person might eat over the course of a year, but divided by the number of meals that person eats in a year, and combined into one unusually average meal.

Your net water and land use and GHG emissions since your first HumanHerbivores general estimate compared to an average global individual who consumes the same amount of Calories per day.