Presliced fruit sure saves time. But here's what you miss out on when you buy it: vitamin C.

Research shows that presliced fruit may have less vitamin C by the time you eat it than if you'd bought whole fruit and sliced it yourself.

The Whole Picture
Kiwifruit, pineapple, and cantaloupe seem particularly prone to vitamin C loss, according to John La Puma, MD, author of ChefMD's Big Book of Culinary Medicine. (Browse the book online.) See how high in vitamin C your favorite fruits rank with this online tool.

More Ways to Make a Good Thing Better
Why stop with whole fruit when you want to make the most of good foods. Here are more top choices for making a good thing even better.

• Heat your olive oil this way so you don't kill the health benefits.
• Cook broccoli to this temp to help preserve the cancer-fighting sulforaphane.
• Use this green veggie within 4 days of purchase.
• Let this fruit sit on the counter a while before you slice it.
• Think stinky when it comes to picking out this bulb.

Read this article for tips on fresh vs. frozen veggies and how microwaving affects nutrition.