10 kcal/kcal is false
The reason that 10kcal / kcal seems high is that it is not correct.
Take corn for instance, which is a starting point for many foods, and is probably similar to other grains.
The cradle to finished corn energy requirement is 900kJ/kg (including fertilizer production). This equates to about 0.25 kcal/kcal in the corn kernels. In addition to the low energy requirement required, additional CO2 is converted to O2 by the corn. The reason that you get more energy out than you put in, is that the corn is utilizing energy from the sun. The reason that converting corn to ethanol becomes about equivalent to just using gasoline, is that the corn must be converted to ethanol by microbes. It is then in a dilute beer, which must be distilled to remove the water. The distillation takes up the balance of energy, so that 1kcal is used to produce 1 kcal of ethanol.
The biker who displaces driving, say by riding 10,000 miles/yr, will increase his/her diet mostly by increasing carbs. For instance by eating more corn, wheat, and soy. This person most likely doesn't just eat a ton more meat, which would be terrible for their diet, and hard to keep down. It would take a lot of meat.