Misconceptions about exercise

Q. Is it true that you lose more body fat by exercising in the low-intensity fat-burning zone?

A. No. The notion that slow exercise burns more fat is a misinterpretation of the research.

Of all the calories you burn during exercise, a greater proportion comes from fat during low-intensity than during higher-intensity exercise. However, you generally burn significantly more total calories and therefore more total fat with higher-intensity exercise. So, if you hit a plateau, increasing your intensity may actually help you burn more body fat.

If low intensity exercise is what's enjoyable for you or what your doctor has said is safe for you, then rest assured that you just need to keep at it longer to burn more calories.For ideas to get moving, visit the Physical Activity page at aicr.org.

Q. How do I know which vegetables and fruits are really best when antioxidant scores seem to vary?

A. Keep in mind that antioxidant scores are just one measure of how beneficial vegetables and fruits are to our overall health. Cancer protection also comes from effects of compounds that promote healthy DNA, slow growth and promote self-destruction of cancer cells, block carcinogen formation and more.

If you do pay attention to the scores, know that there are different methods of testing antioxidant levels in vegetables and fruits, and the tests give varying results. You might most often see vegetables and fruits rated by their ORAC scores, but other tests, such as TOSC, FRAP and TEAC also test antioxidant power. The problem with all of these is that they are strictly chemical "test tube" tests; they can't represent the effects of eating these foods.

Actual effects vary with how much of the antioxidant compounds we absorb from foods, how stable the compounds are within our body and how much of the compound gets into and works in our cells.

Several newer methods developed now look at how compounds are taken into cells and metabolized. According to one system (developed at Cornell University), the vegetables highest in antioxidant activity within our bodies include broccoli, carrots, beets, red pepper, asparagus, eggplant and brussels sprouts. Highest antioxidant ratings for fruits went to pomegranates, blackberries, wild blueberries, strawberries, raspberries, cranberries, cultivated blueberries and apples.

It's important to note that all 27 vegetables and virtually all 25 fruits tested showed signs of fighting cancer cells. So don't make antioxidants the only basis for choosing vegetables and fruits. Good nutrition is much simpler than that: aim for a wide variety and large portions that are part of every meal.

• Provided by the American Institute for Cancer Research. Learn more about the group at aicr.org.