I've always challenged this line of thinking with the following: If you think driving a Prius to work is nearly as efficient as riding a bike in terms of energy usage, just trying pushing your car to work.

I've run some numbers on myself and and have calculated that I get the equivalent of 435 miles per gallon, comparing the Calorie content of petrol to the number of Calories I burn commuting. The Prius burns 750 Calories per mile in petrol going down hill with a tail wind. The model she's probably using assumes that the energy cost of producing crude oil is zero. What happens when we start having to grow our fuel instead of just take it from the gound? We're already putting up to 15% corn-based ethanol in petrol now, I think. I doubt the oil companies are going to publish how much coal and oil it takes to produce a gallon of petrol, since oil wells and refineries run on coal-fired electric plants. There's simply no 1:1 comparison here. I think to be intellectually honest about this, you have to look at the amount of energy used per mile as opposed to how many dairies and cattle ranches it takes to feed hungry bike commuters. When you start going down that line of reasoning, you enter the domain of the population control advocates.