Good article for people getting started. One mistake I think a lot of trainers make is that they take someone who doesn't work out and wants to get in shape and then they push push push them to the breaking point at the very first time- happens on tv a lot.
IMO that's the worst thing you can do since they can't handle it and it makes them feel miserable and of course that would turn them off to working out. Now if you take someone who's in shape and give them a hard workout, the harder the better.
Same for eating, you can't just take a fat person and do a complete 180 on there diet. They'd hate it and go immediatly back to there regular diet.
If you're starting off you've gotta take it step-by-step which is exactly what the article suggests. But of course if you're a runner or someone who's already in shape, there's no reason to stop and walk unless you're dong sprints.