One smoothie sold in New Zealand by the Tank chain and advertised as a "meal in a drink", including oats, peanuts and honey, contains more than 2300 kilojoules of energy in a large, 475ml serving. That is about of fifth of the median daily energy intake for men and a third for women.
Australian consumer organisation Choice analysed more than 90 smoothies and frappes from shops and said that while eating fruit-based foods seemed good in theory, "the inclusion of fruit concentrate and added sugar - in serving sizes that can be larger than an average plate of food - poses serious health issues for people consuming these drinks as between-meal snacks."
Health authorities recommend eating at least two servings of fruit a day, one of which can be a cup of fruit juice.
But instead of all whole fruit, commercial smoothies often contained fruit concentrate, Mr Quigley said.
"The labels often say 'real fruit', but the fruit has been concentrated into puree/jam. All the good fibre has been removed, leaving unreal sugar levels. And then on top of that, even more white sugar is added as an ingredient.
"The sugar in fruit is great. Normally if you eat a banana it's still within a cell wall. You're getting quite a small amount of sugar and there's quite a lot of water in there."
He did not drink smoothies from shops because of the extreme sugar content and would not offer them to his children. Homemade smoothies were healthy if made from ingredients such as a banana, trim milk, some berries and maybe a scoop of icecream.
Dietitian Dr Rosemary Stanton told Choice that regularly consuming large amounts of fruit sugars without fibre was not ideal.
"Most people would be unlikely to get through four apples, but could easily manage the equivalent in juice."
