What is: a berry, loaded with fat and fiber, sometimes called an alligator pear, and according to researchers offers far-ranging health benefits, including banishing belly fat? (All that and guacamole, too.) 

An avocado.

A recent study in the Journal of Nutrition found that when women who are overweight or have obesity eat an avocado a day for 12 weeks, they lose measurable amounts of visceral belly fat.

And that's even though one Haas avocado contains around 320 calories — 245 from fat — and 29.5 grams of total fat, of which 24 grams are poly- and monounsaturated (the good kind) fats.

So what makes this flavor- and calorie-rich berry so good for you?

The researchers think the fiber and monounsaturated fatty acids may play a major role. A whole avocado contains around 10 grams of fiber — about 40% of women's daily recommendation — and we know the more fiber in a diet, the less visceral belly fat you'll have.

In addition, insoluble fiber (70% of the fiber in an avocado) increases intestinal bulk and shortens transit time, lowering absorption of excess calories.

Avocados' other benefits include:

• A nutritional boost from vitamins C, E, K, and B6, riboflavin, niacin, folate, pantothenic acid, beta carotene, magnesium, and potassium. 

• Support for healthy cholesterol levels: In 3.5 ounces of avocado, there are 76 mg of a plant sterol that contributes to control of bad LDL cholesterol.