Grotto does note that there is something unique about acai: It's one of the few fruits, besides avocados, that contain monounsaturated fats (MUFAS).
While MUFAS may work to help keep you feeling satisfied if you include them in a calorie-controlled diet, the amount in acai is so small that you would need to consume large quantities to get enough MUFAs, he says. And not only would that be expensive, he says, it would add lots of extra calories. (MUFAS are also found in olives, avocados, nuts, seeds, dark chocolate, soybean, flax, and olive and sunflower oils.)
Beware 'Free' Trials of Acai Weight Loss Products
Not only has acai not been proven to have the weight loss powers claimed in some of the ads, consumer groups warn that people who sign up for a "free" trial of acai diet products can get burned.
The Center for Science in the Public Interest, a food and nutrition watchdog group, recently issued a warning that many companies offering free trials of acai diet products actually end up charging customers. Customers are asked to supply credit card information for shipping of the "free" sample, and some have immediately been hit with monthly charges of $80-$90.
The Better Business Bureau of Northern Indiana offered a similar warning against online ads for acai weight loss products.
What Is the Acai Berry?
Grown in the Amazon River basin in Brazil, acai is a deep purple berry that tastes like a combination of wild berries and chocolate.
The berry's anthocyanin content gives it its rich purple color. Anthocyanins are powerful antioxidants that may protect the body against cancer, inflammation, diabetes, aging, neurological diseases, and bacterial infections.
A 4-ounce serving of pure acai contains about 100 calories, iron, calcium, fiber, vitamin A, and 6 grams of fat -- but because the berries do not transport well, most food products sold commercially use only a small amount of pure acai. Acai is available in capsules, powdered, as frozen pulp, and in bottled smoothies and other drinks.
If you're considering buying acai products, read the labels, because the drinks may contain lots of added sugars and calories. And, be prepared for sticker shock at the grocery store, as most acai products carry a hefty price.
"Products made from acai are expensive because 95% of the berry is seed, and only 5% is the skin used to make food and beverages," says Grotto.
Keep in mind that you can get similarly antioxidant-rich whole fruits and vegetables for a fraction of the cost of acai, and in their natural form (without extra sugar or calories). Blueberries, blackberries, and raspberries are more economical choices that deliver similar health benefits, says Grotto.