Protein or fiber -- which one helps us feel full? We'll explore that and more as Registered Dietitian Marilyn Wadum answers questions from the Food for Thought mailbag.

One question involves fiber versus protein: Which one makes us feel fuller?

Marilyn says, "To feel fuller you're going to concentrate on more fiber. The protein source would be to prevent hunger in between meal times."

Vitamin D has been in the news a lot lately. Why is it so important?

"Vitamin D is very important for us to be able to absorb our calcium. The best source is 10-15 minutes of regular sunlight every day. During those months that it's rainy or dark we're going to want to look for either a Vitamin D supplement or get supplemented milk or fruit juice."

We all know wine can be good for our health, but should we opt for white or red?

"The red wine is going to have more phytochemicals or antioxidants so we would recommend four to five ounces of red wine per day."

What about calorie counts? How many do men and women need?

Marilyn says "Calories for men and women vary by age, size, and height. Average people would be 2,000 calories for women and 2,200 calories for men."

Another question involves cutting down on processed food. What can remain in the diet?

"Most of our food supply is processed in some way," Marilyn says. "But the best processed food would be cereals because they're fortified with multiple vitamins and calcium."

Most of us have noticed slim drinks on store shelves. Are they safe to drink?

"The slim drinks probably have a stimulant like caffeine or Echinacea and I would highly recommend limiting those to two to three serving per day, just as we'd limit caffeine to that amount."

From a nighttime snacker comes the following: What time should we stop eating?

Marilyn says "A usual time to stop eating for the day is about two hours after dinner. So if you eat at 5, 6, 7 at night we want to stop eating so that we can do our digestion. However, the total amount of calories for a particular day is what counts for weight gain or weight loss."