The worst-case production of plant-based foods actually comes out ahead compared to best-case production on virtually every environmental metric including emissions.

If I source my beef or lamb from low-impact producers, could they have a lower footprint than plant-based alternatives? The evidence suggests, no: plant-based foods emit fewer greenhouse gases than meat and dairy, regardless of how they are produced.

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Plant-based protein sources – tofu, beans, peas and nuts – have the lowest carbon footprint. This is certainly true when you compare average emissions. But it’s still true when you compare the extremes: there’s not much overlap in emissions between the worst producers of plant proteins, and the best producers of meat and dairy.

https://ourworldindata.org/less-meat-or-sustainable-meat

More broadly

Plant-based foods have a significantly smaller footprint on the environment than animal-based foods. Even the least sustainable vegetables and cereals cause less environmental harm than the lowest impact meat and dairy products [9].

https://www.mdpi.com/2072-6643/14/8/1614/htm

Transportation doesn’t actually make as much impact as one might think

Transport is a small contributor to emissions. For most food products, it accounts for less than 10%, and it’s much smaller for the largest GHG emitters. In beef from beef herds, it’s 0.5%. Not just transport, but all processes in the supply chain after the food left the farm – processing, transport, retail and packaging – mostly account for a small share of emissions. This data shows that this is the case when we look at individual food products. But studies also shows that this holds true for actual diets; here we show the results of a study which looked at the footprint of diets across the EU. Food transport was responsible for only 6% of emissions, whilst dairy, meat and eggs accounted for 83%.

https://ourworldindata.org/food-choice-vs-eating-local

In terms of health, one can live perfectly fine and healthy on a plant-based diet

It is the position of the Academy of Nutrition and Dietetics that appropriately planned vegetarian, including vegan, diets are healthful, nutritionally adequate, and may provide health benefits for the prevention and treatment of certain diseases. These diets are appropriate for all stages of the life cycle, including pregnancy, lactation, infancy, childhood, adolescence, older adulthood, and for athletes. Plant-based diets are more environmentally sustainable than diets rich in animal products because they use fewer natural resources and are associated with much less environmental damage. Vegetarians and vegans are at reduced risk of certain health conditions, including ischemic heart disease, type 2 diabetes, hypertension, certain types of cancer, and obesity. Low intake of saturated fat and high intakes of vegetables, fruits, whole grains, legumes, soy products, nuts, and seeds (all rich in fiber and phytochemicals) are characteristics of vegetarian and vegan diets that produce lower total and low-density lipoprotein cholesterol levels and better serum glucose control. These factors contribute to reduction of chronic disease

https://pubmed.ncbi.nlm.nih.gov/27886704/