Speed walking? lol.
I run X-country and we do what some people call HIIT. High Intensity Interval Training. Which is excellent way to lose bodyfat.
It is running short/medium distance (200 to 400 - which is 1/2 - 1 lap on a track) at 80-90% with good rest in between.
One time in track (distance track, where I trained with milers and 2 milers, but I was a 200/400/800 guy) we did 20 x 400s. Actually only me and 2 other guys did. It was the max you could do. So we both got a nice reward

Anyways, I lost so much
weight the week following.
Another time I lost
weight was when I ran a 5k invitational. 5k = 3.1 miles. Ran it in a slow ass 20:14 cuz I was out of shape, but I ran hard. I was 182 solid for 3 weeks prior and dropped to 180 the day after.