Burning Rubber & Calories at the Supermarket

Looks like Britian's biggest supermarket chain, Tesco, wants to help its customers keep to their weight loss goals - even as they roll down the bakery and frozen food aisles. According to a story in today's Wall Street Journal:

Tesco...is testing a new 10-speed shopping cart designed to help shoppers burn extra calories as they round the aisles. The "Trim Trolley" has a large rear wheel that provides adjustable resistance and a handle-bar monitor that lets shoppers watch their heart rates rise and count calories burned.

A typical 40-minute trip around the supermarket burns about 160 calories. Pushing the Trim Trolley, with the resistance level set at seven out of a possible 10, the average person would burn up about 280 calories in that time, says the cart's designer and marketing consultant Wayne Asher.

What's next? Weighted whisks? Stairmaster-powered blenders?