Health experts are dismayed that summer smoothies marketed as "98 per cent fat free" and "with an abundance of nutrition" contain more kilojoules than a Big Mac, and are urging consumers to steer clear.
A survey of 40 popular smoothies, frappes and shakes found Gloria Jean's "98 per cent fat free" Mango Fruzie in a large size had the highest amount of sugar, containing an alarming 123 grams or 31 teaspoons' worth.
The Mango Fruzie has nearly double the sugar content of a 600ml bottle of Coca-Cola Classic, rocketing its kilojoule level to beyond that of a McDonald's Big Mac.
"Food outlets use phrases like 97 per cent 'fat free' or 'dairy free' to make their smoothies and frappes sound healthy, but ... these drinks can actually do more harm than good," said Alison Ginn from Livelighter, the government-funded program that conducted the survey.
The World Health Organisation's new nutrient guideline shows added sugars should make up no more than 5 per cent of an adult and child's daily energy intake – or six teaspoons per day – for the biggest health benefit.
"Like with soft drinks and other sugary drinks, regular consumption of frappes and smoothies can contribute to weight gain and a build up of toxic fat around your organs, which increases the risk of type 2 diabetes, heart disease and some cancers," Ms Ginn said.
Half of the 40 store-bought drinks analysed had more kilojoules than a Big Mac, including the healthy-sounding Mango Fruzie and two from Boost Juice.
Boost Juice's Brekkie to Go-Go Super in large was loaded with 24 per cent more kilojoules than a Big Mac and its Black Label Protein Supreme "with an abundance of nutrition", also in large, 12 per cent more.
The researchers only took the amount of kilojoules, fat and sugar into account. They did not consider the amount of dietary fibre, for example, and its benefits.
McDonald's Mocha Frappe and Coffee Kick Frappe, both in large, had the greatest amount of saturated fat – about 21.7 grams each – double that of a Big Mac, which has 10.7 grams.
The average Australian should not consume more than 16 grams of saturated fat per day
"Milkshakes, thickshakes, iced coffees and frappes, which are laden with cream and/or ice cream, were also alarmingly high in saturated fat – some have more saturated fat than we should consume in an entire day," said Roni Beauchamp from Heart Foundation Victoria.
"For good health we should aim to limit saturated fats in our diet as they can raise cholesterol levels and put us at greater risk of heart disease."
Of all 40 summer drinks analysed, McDonald's Large Mocha Frappe was deemed the worst. It had the highest amount of kilojoules, fat and saturated fat.
"If you do decide to have one of these drinks, you can limit the damage by asking for skim milk, choosing the smallest cup size available and sharing with a friend. Better yet, make your own version at home so you know exactly what you're drinking," said Ms Beauchamp.
A spokeswomen for Boost Juice said comparing its products to that of a Big Mac or a soft drink was not a true comparison because of the empty calories in junk food.
"When you are consuming something that contains wholesome ingredients such as fruit, vegetables or milk, your body is getting important nutrients, which this study did not take into consideration. All Boost Juice's nutritional information is readily available in-store and online," she said.