The analysis looks about right although I agree that the calorie estimate seems a little high unless you're either rather massive or rode quite fast. One contributing factor is that gasoline costs are very low in terms of cost/Calorie and another is that food costs vary widely depending on the type of food and the amount of service/labor involved.

Gasoline in the US is less than 10 cents per 1000 Calories while it's pretty hard to get overall food costs down below a dollar per 1000 Calories. But you can easily do better than the $5 - $7 estimate based on the pizza. E.g. a peanut butter & jelly sandwich is a good recovery food and costs a little under $1 per 1000 Cal. when the ingredients are bought at supermarket prices. That would make your bike ride fuel significantly cheaper than your car fuel for the same length trip.

BTW 'Bah Humbug', relying on the economics for the poorer countries in Asia may be misleading. Compared to the US they tend to have much lower food costs and somewhat higher gasoline costs.