I read a carbrain article a while ago that tried to argue that cyclists create more CO2 than a car.

So to compare that they assumed that

• The cyclist eats exactly as much calories as required, so that extra exercise directly requires an increase of caloric intake. They did the same for the driver.
• The cyclist exclusively covers the added caloric intake via imported japanese Kobe beef steak cooked on a wood grill.
• The car was the lowest-consumption electic car they could find.

And with that setup the cyclist actually created more CO2.

The author seriously booked that as a win for the car, claiming that cycling is not always better for the environment than driving.