Supporters of barefoot running make a variety of claims about its virtues -- but what does the scientific evidence actually say? Give Barefoot Running the Boot?
Based on personal experience, I'm surprised by a couple of points: first, that shoe weight (up to 300 g, or 10.58 oz) did not have a negative impact on performance, and second, the researchers found no difference between shod and barefoot movements in their ability to strengthen certain muscles.
Not surprising, researchers did not go out on a limb to support the use of shoes, rather made the point: "it is not known whether people running barefoot have more, equal, or fewer injuries than people running in conventional running shoes."
Keep in mind this was not an actual study, rather a review of current studies already published. You can be sure there is more to come on this.
My take is this- barefoot running is probably optimal if everybody ran on a soft grassy surface. The amount of protection required to run on roads is purely individual, and some of the minimalist shoes out there probably don't offer enough for the majority of runners, particularly those running high mileage.