And to to all the vegans, your petrol and electricity come from animals (dinosaurs). True vegans live in caves and walk everywhere (if they have enough energy).
Pretty sure my cucumbers grow faster than any chicken or pig. They (my cucumbers) probably drink less too. How should I factor in the chook and pig poo I put on them to grow I wonder? Does it matter that I grow my own chooks? Oh crap, maybe I should just eat McDonalds. Oh, but then there's the 320 km return trip to counter in.
Damn those clickbait articles, they never have the answers after throwing up the questions.
That article is a crock. It seems to be purely about calories. Lettuce and celery and others are very light on for calories but they have lots of phytonutrients. I think iceberg is pretty useless but others are very good. If you want calories look at nuts and berries. They are full of fat and sugar. For protein peanuts have the same proportion as beef, other nuts a bit less.
If the alternative is animal products they require more inputs because half the calories in feed are lost in animal metabolism. I doubt that transport costs per calorie would be higher for agricultural products when you consider the packing density. Lettuce yes, wheat no.