Picture the scene: local bookstore caf. I'm such a regular there that the entire staff knows me, and my kids, too. I've rattled off the kids' standard order already, but my autopilot stalls before I can add my usual splurge, a decaf mocha (XXX grams of carbohydrate).

"Uh" What do I want? For the first time in weeks I actually look at the menu, and realize it's completely new. Whoa. Wait a minute there's actually a new sugar-free coffee drink.

Judging from the reaction of the barista, it's pretty funny to see a 40-year-old mother of three doing a (very brief) Snoopy-style happy dance in a bookstore caf. "Yes, yes, I'll get that! Thank you very much!"

It was delicious, all the more so for being unexpected and guilt-free.

Bookstore cafs, following the lead of Starbucks and dozens of other coffee house chains, have popularized coffee drinks beyond all sanity. It would be one thing if we were all drinking actual coffee, with a splash of half-and-half and a packet of sweetener. That comes in around 10 carb grams if you use 2 teaspoons of sugar. If you use a non-caloric sweetener, you can get it to around 2 or 3 grams.

But that's not what we're drinking. We're drinking "blended coffee" creations that taste vaguely related to coffee, under all the syrupy flavors and whipped cream. I'm sure there's coffee in them somewhere, and they do taste good (if your tastes run towards the very sweet). But a 16 ounce coffee drink can easily cost you 50, even 60, grams of carbohydrates. For many low-carb dieters, that's an entire day's carb allowance.

That one 16 ounce drink contains easily 400 or more calories, too. What do you think happens to all those calories when they're delivered in one huge dose of simple carbohydrates?

Your metabolism responds to the inrush of sugars by pumping out insulin to regulate your blood sugar: too little sugar results in hypoglycemia, too much, diabetes. The insulin pushes the excess sugar out of your bloodstream. Some is used for muscle energy, but the rest gets stored away as fat.

But the fun doesn't stop there. After a while, maybe an hour or so, the insulin that has been herding up all that sugar finds itself with nothing to do. The sugar has all been metabolized, but you've still got all this insulin in your system.

That's when you find yourself starving, even though you've most likely eaten more than enough calories to get you to that point in the day. It's as if you never ate those calories, because the insulin in your bloodstream now doesn't have any way of knowing what you ate earlier. It's circulating freely and hitting your appetite centers, and it will keep doing so until you eat something else and give it something to do.

You may be able to mitigate the effect of the sugar rush somewhat by eating something with protein, which is metabolized more slowly, while you're drinking your coffee. The problem here is that the foods typically eaten with coffee drinks donuts, or bagels and cream cheese just add to the carb burden.

The best bet is simply to avoid the blended drinks. I know, they're yummy, so hold on a second. I would never personally advocate giving up coffee, even though some low-carb diets recommend it. I've been decaffeinated for years but I still love coffee. So here's what I do, and you can do, instead:

Order a regular coffee (hot or iced) with a shot of sugar-free syrup, and use half-and-half to lighten. Most coffee houses have at the very least sugar-free vanilla and hazelnut syrups, and some have many other options.

Ask if the barista can blend a sugar-free iced coffee drink for you. They've got blenders, usually, and they know how to use them. It may take a little longer than just grabbing the pre-made blend, but it will probably taste better because it's fresh.

If you like to make coffee drinks at home, look for sugar-free syrups in your grocery or specialty store, in the coffee aisle. DaVinci and Torani are two popular brands that sweeten their syrups with Splenda, the brand name for sucralose. Splenda is heat-stable and has little to no detectable aftertaste, and it's the sugar substitute of choice for many low-carbers.

Both DaVinci and Torani have an unbelievable selection of flavors (gingerbread is a favorite of mine), which can also be ordered online.

If you're a fan of the powdered instant flavored coffee drinks you can buy at the supermarket, check out Keto's line of flavored coffees online at Keto.com, or you can make your own: