Is cycling better than walking to lose weight? I want to lose weight. I commute to my office daily by walking 3 kilometers. If I buy a bicycle and use it for commuting (total 3 km daily), would it be better than walking?
This research claims around walking 334 kilojoules of energy expended for a 1.6km walk

Using the same 1.6km distance, if you cycled at 20km/h at 70watts (arbitrary but vaguely-plausible numbers), you would be involve around 20 kilojoules being "sent to the pedals". Assuming you are about 20% efficient, that would be 100kilojoules burned

For that distance, at a relatively leisurely pace, walking uses more energy.

However, there is more to it than that:

Cycling is a more efficient means of transport. Both methods may use similar amounts of energy, but cycling will be faster. This means you could cycle a longer route to work, "burn more calories", and still get to work at the same time.

Then again, cycling has it's drawbacks - it requires more supporting equipment (a bike being the main part, also things like a helmet, puncture repair kit, maybe lights, and of course somewhere to securely park the bike)

..but really, the most important factor is doing something. Maybe choosing cycling would mean you would spend months saving up the money before you even start? Or maybe you'll enjoy cycling, and start going on longer rides, for fun?

Finally, remember the natural reaction to more exercise is simply "eat more". It is hard and requires conscious effort to go against this (to increase exercise without eating more)