I always recommend tracking calories to patients trying to lose weight. The simplest analogy is money, and the currency of weight in our bodies is calories. Before you buy anything, you need to know how much it costs.
Calorie counting can be difficult and while there are many free online services that can help track calories (www.sparkpeople.com, www.fitday.com) they still require hunting for calories.
No more. Enter Training Peak's Calorie Scanner which conveniently fits on your keychain and then scans the barcodes of the foods that you're eating. Couple that with Training Peak's online/desktop calorie software and all of a sudden those barcodes translate into calories and nutritional information.
Only problem I can see is that my from scratch spaghetti sauce doesn't come with a barcode.
Cost is a bit steep as well - $216.30 for a scanner with a one year subscription.