One study found that for overweight individuals, the stroll may be even more effective at shedding pounds.
Researchers from the University of Colorado found that obese women who walked slowly over a given distance burned more calories than if they stepped it up.
The lead author of the study, Ray Browning:
The results show that people who walk a mile at a leisurely pace burn more calories than if they walk a mile at their normal pace. In addition, those who walk at 2 miles per hour rather than 3 miles per hour reduce the loads on their knee joints by up to 25 percent.
One caveat: Walking slowly may burn more calories than walking briskly, but it doesn't improve cardiovascular health. For that you need to complement your routine with something that will get your heart pumping such as cycling, swimming, or stair climbing.
For a summary of the study:
Walk Slowly For Weight Loss, According To CU-Boulder Study
Study: Slow Walking May Be Best for Obese
For the study itself:
Obesity Research, May, 2005 (Abstract only, subscription required for full article)
Energetic Cost and Preferred Speed of Walking in Obese vs. Normal Weight Women