[StanislavPetrov]

This depends on what you consider "extensive".

About 10 years ago I started taking 45 minute daily walks with no other changes in my diet or activities and the extra weight (about 15 lbs overweight) melted away. I made absolutely no effort to eat less and didn't get any hungrier.

[xedrac]

Walking is quite special in this regard, because it doesn't seem to result in the same compensatory eating that more intense exercise does.

[Mawr]

That depends on your pace and your previous level of activity. If the pace is average and your previous level was ~0 then yes, you're expected to benefit a lot for not much effort.

But to answer your question, walking at average pace is not extensive exercise by any means. Walking at top possible speed would be closer but would probably still not meet the bar. You'd need to incorporate running at moderate pace with a few periods of all-out sprinting into your walking routine.

[nottorp]

One could say that your eating habits were borderline enough to maintain your current weight.