The prevalence of less/fewer errors everywhere is astounding. I saw a national ad on TV the other day with 'less calories' featured prominently. This error was the first thing I noticed on the page as well... but I'm guessing we're in the minority here.
All that said, the product is fantastic. Have been using it for a year on an almost daily basis.
Less energy, fewer calories. My understanding is that it's not continuousness or discreteness that determines whether "less" or "fewer" is appropriate, but whether the noun the word describes is a "count" noun or a "mass" noun. Mass nouns are just nouns you can't pluralize, but can refer to a multitude of something (you can't own "furnitures"), and count nouns are nouns that only refer to a multitude of things when plural.
All that said, the product is fantastic. Have been using it for a year on an almost daily basis.