"As a cyclist, you claim to care about the environment, yet you consume food. Checkmate libs!"

Unfortunately it does not have to be satirical. We have this idiot professor of economics, Reiner Eichenberger, in Switzerland who calculated the same kind of shit for an article in a business newspaper (Handelszeitung).

He said an efficient car using 5 l or 12 kg CO2 per 100 km with four people is more efficient than a cyclist who needs 2500 kcal per 100 km, so they have to eat 1 kg of beef which emits 13.3 kg CO2. Therefore the people in the car are 4 times as efficient per passenger kilometers.

People got quite cross, there were replies by other professors in other magazines to tear him and his shitty assumptions to shreds.

He assumed this ridiculous beef-only diet. Potatoes or pasta would be around 0.5 kg.
He included CO2 in the production of the beef but not of the gas. That would amount to another 50% or so.
He assumed a more efficient than average car for Switzerland, 7l would have been fairer. And on shorter distances it gets worse, e.g. on daily commutes.
He assumed 4 people but cars on average carry around 1.5.
He ignored grey energy in the car and bike production, which would make the bike look way better. Whenever he's railing against EVs he includes grey energy because then it makes traditional cars look better.
There are also some hard to calculate benefits for public health in cycling.
Cycling for travel might substitute other sports activity that would have used the same amount of food.
Cyclists generally cover less distance than drivers. A 1-to-1 comparison the same distance might not be sensible in the first place. If you cycle you try to find nearby destinations, so from a public policy perspective encouraging more cyclists also implies less total distance traveled.
- Cyclists generally cover less distance than drivers.
  My partner recently had her car MOT done and I can confirm I cycle more than she drives in a year. Would be very interested to know the average speed of each though as I can often cycle past cars that are waiting at the lights but the bike path is flowing freely.
- Also, the driver and passengers still burn calories while just sitting in the car.
As ridiculous as this is, especially with the dumbass assumptions, it would actually be kind of a fun interesting calculation. Not that it has any environmental merit, because what about people who drive to the gym, or me who takes the tram to the pool to swim laps there, etc, but just sorta fun.
- E-bikes sit in a weird spot where the amount of human effort saved is substantially higher than the carbon footprint of the components.
  Which implies the optimal transportation mix would be electric trains+trams with e-bikes to go the last few miles.
  
  Can you elaborate on the first bit? It's counter intuitive, considering electricity needs to be produced somehow, so I'd love to learn the background.
  
  Usually using electricity in something like an electric car requires more emissions to generate the power than would be emitted from the food and respiration required to walk the same distance.
  Bicycles are interesting because they improve efficiency so much that it offsets the emissions needed to make the bike, and e-bikes are able to leverage that high efficiency to get 80+ km of travel per KWh (compared to ~6 from something like a Tesla)
  
  That is super interesting, thanks! Granted, public transport transports more than one person, so if possible, it's still much more efficient, and batteries are made of very finite resources, which is a whole different issue to consider.
  
  True! A fully loaded train is about the most efficient way to move humans from one place to another, and has been for over a hundred years.
  Lithium is limited, but you can make 150 e-bikes with a single electric car battery. If we could figure out some sort of solid state sodium battery chemistry it wouldn't even be an issue.

Or at least a dig at someone being overly pious. My brother for a while was unbearable about his 2 x EVs saving the world while living in a city with at least 6 public transport alternatives within 100m

Absolutely. It’s quite funny.