Quick Answer — How Much CO2e Does Your Diet Produce?
Weekly food emissions are simply the sum, across each protein category, of (grams ÷ 1,000) × its kg CO2e-per-kg factor. The factors vary enormously by food — this is the part most diet-footprint tools flatten into a single 'meat vs. plant' toggle, which hides where the actual leverage is.
The factors this calculator uses (kg CO2e per kg of product, Poore & Nemecek 2018 global averages): Beef 99.48, Pork 12.31, Poultry 9.87, Fish (farmed avg) 13.63, Eggs 4.67, Plant-based protein (tofu/legumes blend) 2.0.
What that means per serving: a 170g (6oz) beef serving carries about 16.9 kg CO2e — roughly the same footprint as 8.6 kg of poultry or 57 servings of the plant-based blend at the same 170g size. Beef is not just 'somewhat higher' than the alternatives; on this dataset it is 10x the footprint of pork by weight and over 49x the plant-based default.
This calculator totals your actual weekly grams across all six categories, converts to an annual figure, and — the part most calculators skip — lets you model swapping a percentage of your animal-protein grams to plant-based protein to see the exact annual CO2e saved.