[PaulDavisThe1st]

Cycling is roughly 5x more efficient than running/walking for similar effort. Thinking you will lose much weight by cycling is generally mistaken, unless you plan to cycle very long distances or are extremely obese already and do very little existing exercise (and this is discounting most of what TFA is saying too).

[bagacrap]

wouldn't efficiency correlate to effort? pretty sure the "effort" is the feeling of burning calories. If an elite athlete can run for an hour and burn 2000 calories in that time, they will beat a less elite athlete who can run for 1900 calories in an hour, all else equal. Put them on bicycles or a rower and they'll be able to burn the exact same number of calories (assuming sufficient training in the target exercise medium) because the limiting factor is their body's ability to process oxygen, not the exact form factor of the exercise.

[ehnto]

I'm not sure it makes sense to look at it that way either. What if it takes you 100 calories to move 100 meters but your competitor only takes 80 calories to move 100 meters?