Foods go in and out of vogue, and hummus dip made from garbanzo beans is now a favorite appetizer at casual dinner parties and potluck suppers.

It tastes rich and creamy and seems like it might contain lots of calories and bad fats, but in reality hummus is made from a nutritious legume and blended with healthy oil.

In consumers' quest to steer clear of any fat in their diet, many people are overlooking foods with fats that are beneficial for their body.

Some people also worry that fruits with sugar should be avoided because they hear sugar is not healthy. While nutrition experts say highly processed products containing refined sugar should be avoided, fruits contain naturally occurring sugar and are loaded with so many valuable vitamins and minerals they are considered cornerstones to a balanced diet.

Many people watching their weight or trying to eat healthy will feel virtuous if they avoid any fat in their diet, but that may not be a wise strategy.

"You absolutely need fat, but you don't need much. The equivalent of two teaspoons a day is good for adults," said Anne O'Donnell, a nutrition instructor at Santa Rosa Junior College and co-chairwoman of the Consumer and Family Studies Department.

O'Donnell notes that foods with natural, plant-derived oils are sources of essential fatty acids, and the oils are good for skin, hair and cell membranes.

Healdsburg registered dietician and life coach Kathy Nichols recommends monounsaturated fats to her clients, and cites olive oil as a good choice for cooking oil and salad dressing.

She's also a big fan of avocados, which contain monounsaturated fats, but says it's important to monitor the quantity because of calories, and suggests eating only about a quarter of an avocado a day.

Avocados are high in important lipids and vitamins, such as folate, B6 and magnesium, and some people don't get enough of these vitamins in other foods, O'Donnell said. Theses vitamins are important for brain function, and can help reduce mood swings and control irritability.

She suggests eating a few slices of avocado as a snack or mashing part of an avocado and spreading it on bread as a mayonnaise substitute to moisten a sandwich.

She's not completely opposed to using mayonnaise, however, and says it is "pure fat, but it's at least unsaturated fat and has a teeny-tiny amount of egg yolk."

O'Donnell says low-fat mayonnaise, which is minimally processed, is fine if people like the taste, and suggests paying attention to portion size, whether using a regular or low-fat mayo.

At a party when there is a tempting appetizer table displaying dips, cheese and crackers, veggies and olives, O'Donnell recommends the vegetables, of course, but also the olives.

"You need to be careful with olives because they're high in fat, but it's a healthy fat. They also have minerals and vitamins, and they're much better for you than cheese because the saturated fat in cheese isn't good for your heart," she said.

"Variety is your best bet with good fats. You can get it from meat, like chicken, and especially fish, and there's overwhelming evidence that fish is best," she said.

Nichols says a diet that is primarily plant-based is healthiest, and that a guideline for daily meat consumption is to eat a quantity roughly the size of a deck of cards.

Nuts contain a healthy form of fat, but people need to watch the quantity they consume daily.

Peanut butter in moderation, such as one or two tablespoons daily, is good, and consumers should look for peanut butter with no additives. Nichols noted that many commercial brands have high-fructose corn syrup or other sugars added to them.

Walnuts and almonds are significant sources of minerals and calcium, and dieticians recommend eating a couple of small handfuls daily. One way to not overeat nuts is to add them to cereal or salad rather than have them as a snack.

"The biggest mistake is if you eat them in place of a bag of potato chips," O'Donnell said.

Although fruits contain sugar, they are healthy because the body digests it differently than processed sugars, and they're packed with fiber and essential nutrients, Nichols said.

"As with everything else, you don't want to go overboard because any amount of calories in excess can be bad," said O'Donnell, who recommends three to five servings of fruit daily.

Both dieticians stress that it's beneficial to have a variety of fruits throughout the week, because every fruit is a unique package of beneficial nutrients. Dried fruits are a good source of vitamins when fruits are out of season, but with the water removed the sugar is more concentrated, making dried fruits higher in calories than whole fruits.

"You need vitamins from fruit and vegetables that you can't get from other foods," O'Donnell said.

The darker and deeper the color of the fruit or vegetable, the more vitamins, minerals and phytochemicals it contains, O'Donnell said. Notable exceptions are honeydew melon, cauliflower and bananas, all of which are pale-colored but have nutrients important for a balanced diet.

Janet Parmer is a Bay Area feature writer. She may be reached at jhparmer@comcast.net.