Trying to curb your appetite? There's one sure-fire way to do it. Plus something to remember the next time you pick up a can of cooking spray -- Marilyn Wadum answers your questions in this month's food for thought mailbag.

Our first question comes from someone who wants to curb his appetite. Which is better: a small salad or a small cup of soup?

Marilyn says, "Both salads and soups are helpful to decrease appetite, but you get the biggest bang for your buck with broth based soup because the volume, the weight in your stomach will help you feel fuller faster."

Another wonders if one of her favorites, sushi, is a health food?

"It depends on what sushi you have purchased. If you have whole grain rice or cooked fish, that's healthy. But if you have white rice or a lot of avocado in it you need to consider that it wouldn't have a lot of benefit."

We all know fruits and vegetables are good for us but do we really need to wash all of them before eating them?

Marilyn says, "We do recommend all fresh fruits and vegetables are washed prior to eating or cooking. That would mean using a vegetable brush on potatoes or other thin skinned. It could also mean a small amount, just two drops, of detergent in water and wash it through, the lettuce, and rinsing it with clear water."

Are non-fat cooking sprays okay for our health?

"Non-fat cooking sprays are a good addition for our health," Marilyn tells us. "We want to cook with less fat. But remember, once you hold down the can for more than two seconds you start accumulating some calories, possibly 20 calories."