Vegan, Flexitarian Or Carnivore? Here's The Impact Your Diet Had This Year

Do you know how much what you ate this year impacted animals and the planet?

If you followed a vegan, flexitarian, or carnivore diet in 2025, here’s how to measure the effect of your food choices on your footprint, and the world around you.

How to work out the environmental impact of your diet

Photo shows someone's hands as he eats a large cheeseburger made with animal products — Adobe Stock Going vegan could save nearly 200 animals per year

Harvard University’s “footprint calculator” allows users to input the foods they typically eat in a week, as well as the frequency, and details about themselves.

The calculator then estimates the environmental impact of that diet over a year, providing averages and comparisons for context. If you want to roughly calculate your own footprint, this is one of the simplest solutions. (Note: the calculator only includes food-based emissions, so it does not reflect a person’s total footprint.)

Studies indicate that men have the largest climate footprint of all, primarily due to the cars they drive and the amount of meat they eat. Studies also show that the more meat, fish, dairy, and other animal products in your diet, the higher your overall environmental footprint. To visualize and compare, Plant Based News (PBN) input the details of common diets featuring different quantities of animal products.*

For example, according to Harvard’s footprint calculator, a vegan diet might emit around 247kg of carbon, 1,416g of nitrogen, and 240,192 liters of water, which is well below the US national average per capita of 1750kg of carbon emissions per year.

Meanwhile, a vegetarian diet that included eggs, milk, and cheese as well as plant-based staples like rice, grains, legumes, and vegetables might create 512kg of carbon – also below the US national average – along with 4,708g of nitrogen, and 285,036 liters of water per year, for a slightly larger footprint.

Flexitarians, omnivores, and carnivores

Flexitarianism is trickier to estimate, as it might include both meat-eaters who have a single plant-based meal per week, and pescatarians who very rarely eat meat. A flexitarian who regularly eats eggs and dairy but only semi-regularly eats meat and fish might create 882,156kg of carbon, 7,114g of nitrogen, and 303,564 liters of water.

Meanwhile, the Standard American Diet (SAD), which includes plenty of meat, dairy, and fats, could create 1750kg of carbon emissions per year. A typical omnivorous diet might also create around 20,000g of nitrogen and 660,000 liters of water.

According to the footprint calculator, eating a carnivore diet has the biggest impact of all. Someone following a carnivore diet might have an annual footprint of at least 2,592kg of carbon, 35,633g of nitrogen, and a whopping 680,112 litres of water.

The calculator also described the 2.5k of carbon produced by eating carnivore as “far above” the US national average per capita, the second-highest in the world.

Eating vegan could save hundreds of animals per year

Animal agriculture is both the leading cause of climate change and the world’s biggest cause of food waste. Farming animals contributes to deforestation, biodiversity loss, and pollution, and estimates suggest the industry kills at least 1.2 trillion animals every year. As noted by Sentient Media, the total number of human beings that have ever existed is estimated to be 117 billion; less than 10 percent of the meat industry’s annual death toll.

Studies show that opting for plant-based foods, which are more sustainable and efficient than meat and dairy, can cut emissions. Swapping animal proteins for plant-based meat can reduce your overall footprint by nearly 90 percent, and PETA estimates that adopting an entirely vegan diet can save nearly 200 animals per year.

Overall, food production causes roughly a third of all human-caused greenhouse gas emissions (GHGs), while a third of all produced food is ultimately wasted. All food production requires resources and causes emissions, but the current system, which prioritizes animal products, is inefficient and unsustainable.

According to the latest EAT-Lancet report, widespread adoption of the Planetary Health Diet could prevent more than 40,000 early deaths per day and save USD $5 trillion per year through improved climate resilience, environmental restoration, and human health.

Not everyone can avoid eating meat, for a variety of reasons, but many of us are fortunate enough to be able to choose the foods that we buy and consume. Cutting just a few hundred grams of meat every week can still make a significant, measurable impact on your environmental footprint, helping humans, animals, and the planet.

*All PBN‘s dietary calculations here were based on a 30-39-year-old man living in the US. Your footprint will vary depending on your age, gender, location, and overall lifestyle. These results are approximations only.