How many calories will i burn if i walk 5, 000 steps to offset my love of pizzas?

1 slice or less : Keep walking but that is less than the avg calories in one slice.

Will have net gain: Surprise 1000 steps with 2.5 ft stride is one mile , if are 180 lbs walk at speed of 2 ml /hr you burn 100 calories per mile , so 5 miles you will be burning 500 cal, , each slice has 600 to 700 cal ( find out how many cal each slice ) so you will be gaining weight in spite of your long walk !