So, Mr. Organic Cereal Eater. You think your cereal is "greener" than Cheerios?

Think again.

According to a new consumer product-rating Web site called GoodGuide, Cheerios actually rates near the top of the cold cereal list in health, environmental and social performance.

Started by a group of University of California-Berkeley researchers last year, GoodGuide provides a rating system for more than 70,000 products such as toys, makeup, food and household cleaners.

Those products are rated on a variety of measures, from how manufacturing impacts the environment to how workers are treated. The GoodGuide organizers want to give consumers a way to measure the social, environmental and health impacts of a product's entire life cycle, from when it's made to when it's tossed.

The Berkeley team joined with MIT and Harvard professors, and technical advisers from Google, Amazon, eBay andother organizations to form GoodGuide. Data in various forms for the ratings are provided by the Environmental Working Group, KLD Research, Risk Metrics and Asset 4.

Shoppers nowadays are inundated with new products touting their environmental friendliness, even in the big-box stores like Wal-Mart and Target. There are organic cotton clothes, cleaning products that biodegrade and makeup that's not tested on animals.

But there's more to "greenness" than meets the eye. Certified organically grown cotton material can still be sewn into clothes in sweatshops before they make it onto your favorite store's clothing rack. Biodegradable cleaning products make claims that are hard to prove unless the contents are fully listed. And makeup that's "cruelty free" can still contain substances harmful to your health in the long run.

Rating products is no easy task. GoodGuide notes on its Web site that rating systems are only as good as data and a lot of data are missing from products in the U.S.

"Nonetheless, existing data sources may have data gaps when raw information is not available, companies have not yet reported on their performance, or scientists and experts disagree over how to measure performance," according to information on the GoodGuide Web site.

So the results of GoodGuide can be surprising, and perhaps, arguable.

Take Cheerios, one of 293 cereals rated. According to the GoodGuide rating system, itpulled a 10 out of 10 for health and nutrition, an 8.1 for environmental stewardship and a 7.1 for social performance. Cheerios scored lowest in water management, and labor and human rights.

GoodGuide rated Cheerios, which is not organic, better than several organic brown rice and flax cold cereals.

The GoodGuide organizers are looking for feedback and ideas for improving the rating system and adding products. For more information, see www.goodguide.com.