" There's a reason that Tour de France competitors burn 7000 calories a day."
Yes, there is. They're the world's most competitive cyclists, racing at speeds about 3 times higher than your average transportation cyclist, and remember that air resistance is a function of velocity squared. The power they're capable of generating, for hours on end, is nearly an order of magnitude greater than a person who does not cycle regularly.
"Bikes take very little energy to be propelled forward, but they get that energy in a horribly inefficient manner using an energy source with massive environmental impacts."
Aside from the fact that many people over-eat and thus need not consume any extra calories - food distribution is incredibly efficient, the cost of fuel for distribution is built-in to the cost of food, and the number of additional calories needed by someone riding a few miles a day amounts to a very small percentage of their daily food budget. Simply adding a slightly larger portion of carbs - one of the cheapest food sources there is - is sufficient.
There's something like 1600 calories in a box of spaghetti that costs ~$1-2. So an extra 200 calories a day costs about twenty five cents.
How much do you spend on gas per day?