This week I received not two, not three, but four emails from listeners with questions about frozen yogurt and ice cream. Obviously, it’s a topic I’ve been neglecting! Today, I’ll try to tackle all your questions, including whether or not frozen yogurt contains beneficial bacteria, what all those chemicals are doing in low-fat frozen desserts, and which ones might be the healthiest.

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Does Freezing Kill the Beneficial Bacteria in Yogurt?

Grammar Girl has been using her ice cream maker to make frozen yogurt this summer. But she’s wondering if freezing the yogurt might affect the things that make yogurt so good for you. Kelly had the same question about making smoothies with yogurt and frozen fruit.

As you might remember from my episode on Fermented and Cultured Foods (#4), yogurt contains friendly bacteria that help keep your digestive system healthy. But these friendly flora are only helpful if they’re alive when you eat them. That’s why you should look for the words “Contains live and active cultures” on any yogurt package to be sure you’re getting the good stuff.

The good news is that freezing does not kill beneficial bacteria. In fact, it preserves them in a state of suspended animation until you eat them, at which point they warm up and resume their regular helpful activities, like fending off harmful bacteria, aiding with digestion, and producing certain vitamins. So, Kelly, you’ll get all the benefits of the yogurt in your frozen-fruit smoothies.

Does Frozen Yogurt Contain Live Cultures?

But I couldn’t answer Grammar Girl’s question about frozen yogurt for sure without seeing her recipe. Although it might seem an odd way to make a frozen dessert, many recipes start out by heating up milk, adding other ingredients, and then chilling the mixture before adding it to the ice cream maker. The bacteria in yogurt will die if they get any hotter than about 112 degrees F.

In Grammar Girl’s recipe, you heat up milk and sugar until it boils. Then you stir in the yogurt and some berries that you’ve pureed in the blender and chilled. If the yogurt is added to boiling milk, the beneficial bacteria will probably be destroyed. Grammar Girl suggested that if she adds the chilled berries first, it would cool the milk down enough that the bacteria in the yogurt would survive. She’s exactly right. As long as the mixture is cooler than 112 degrees F when the yogurt is added, she should be fine.

And that’s the problem with frozen yogurt you buy at the grocery or ice cream store. It has to contain a certain amount of actual yogurt in order to be labeled frozen yogurt. But if it’s heat-processed--and I’d assume that most commercial frozen yogurt is--you’re not going to get any beneficial bacteria in the finished product.

Most Frozen Yogurt Does Not Contain Live Cultures

If you can find frozen yogurt that’s specifically labeled with the words “Contains live and active cultures,” however, you’ve hit the jackpot. Or, you can make your own! I’ll include Grammar Girl’s recipe for Fat Free Blackberry Frozen Yogurt in this week’s Nutrition Diva email tips. But, Grammar Girl warns that her frozen yogurt bears very little resemblance to the frozen yogurt you buy in the store.

“It freezes hard as a rock,” she says, “but so does every other recipe I've tried. I'm still experimenting to try to make it a better texture.” I think I have some ideas. Grammar Girl’s Blackberry Frozen Yogurt uses skim milk and nonfat plain yogurt, plus berries and sweeteners. Adding a little fat by using 1% or 2% milk instead of skim and low-fat yogurt instead of fat-free would probably improve the texture quite a bit--and might also allow her to reduce the amount of sweetener to boot. So, she might even be able to improve the texture without increasing the total calories.

Smooth, Creamy, and Fat Free: How Do They Do It?

Fats are a natural part of many foods, including most dairy products. When you take them away, the flavor and texture suffers. So how do manufacturers make low-fat and fat-free frozen desserts so smooth and creamy?

Food engineers have been amazingly resourceful about finding ways to fake the texture and flavor of fat. Although it’s quaint to think that it’s simply a matter of churning it twice, that has nothing to do with it. In fact, they use all sorts of emulsifiers, binders, and thickeners to mimic the texture and taste of higher fat products.

That may not be quite as bad as it sounds. Most of these additives are derived from foods like soybeans, eggs, and corn. But it’s not exactly the ice cream Grandma used to make, is it? Then again, it’s a heck of a lot lower in fat and calories than Grandma’s, too, which means we can eat it in vast quantities, right?

See, that’s where it all goes off the tracks. Obviously, if it’s got half the calories but you eat twice as much, you’re breaking even. And if you’re polishing off an entire carton every night, well…maybe Grandma was onto something.

Is A Little Fat So Bad?

Which brings me to Amanda’s question. She’s been standing around in the frozen foods aisle reading labels lately. “I found a variety [of ice cream] made with only natural ingredients,” she writes, “and while it was low in fat, it contained saturated fat.  Another brand contained no fat (and therefore no saturated fat) but it contained maltodextrin, which I have heard negative things about. What would be the better choice for my overall health?”

If it were me, Amanda, I’d probably choose the ice cream with the small amount of saturated fat over the one with all the distinctly un-Grandma-like ingredients. Not only is a small amount of saturated fat not going to kill you, but it will probably taste a whole lot better. Just be sure to keep an eye on the serving size and, of course, no dessert until you eat your vegetables!

Administrative

Visit nutritiondiva.quickanddirtytips.com for a transcript of this episode, along with links to more information on yogurt and frozen desserts and some recipes for making your own. And, if you’d like to try Grammar Girl’s Blackberry Frozen Yogurt , be sure you’re signed up to get my weekly email tips.

If you have a suggestion for a future show topic leave me a voice mail at 206-203-1438 or send an email to nutrition@quickanddirtytips.com. Do me a favor and include the topic of your question in the subject line of your email. Better yet, post your comments and questions on my Nutrition Diva Facebook Page. 

Have a great day and eat something good for me!

RESOURCES: 

Guide to Food Additives (U.S. FDA)

Guide to Yogurt Varieties (National Yogurt Association)

Frozen Yogurt: Nutritious Snack or Decadent Dessert? (Nutrition Bite Blog)

Tangy Frozen Yogurt Recipe (Boston Globe)