It is generally best to chew your fruit and vegetables. While smoothies and juices can have a role in short term dietary programs and as a minor component of the overall diet, we don’t recommend them as a significant source of calories in the long term.

There are more positives in favour of smoothies rather than juicing. Smoothies are more nutritious than juices because the fibre, and any nutrients attached to the fibre, are retained rather than discarded. Consuming fruit and vegetables as smoothies is better than not consuming them at all and having a smoothie for a meal on the run may be better than skipping a meal. If you are sick or debilitated and unable to eat enough then smoothies may be a means of consuming extra calories and nutrients.

Juice fasting and smoothie detoxing seems to be a useful short term strategy for making a complete break from animal products, processed foods, fat, salt and refined sugar (as seen in Fat, Sick and Nearly Dead). However, a smoothie can become a high calorie sugary drink if a lot of fruit is added to disguise the bitter taste of some raw vegetables. Drinking smoothies and juices displaces starchy whole plant foods from the diet. Because whole grains and legumes are strongly associated with good health, it is of concern when people routinely replace a meal with a smoothie – it means there is at least one meal each day where no grains or legumes are consumed.

The popular concept of supercharging the body with phytonutrients has led to more juicing and smoothies. It based on the belief that more nutrients is always better and that an unhealthy diet can be offset by supplements and super-foods. The research evidence only consistently supports the health benefits of eating more plants. Whole plant foods provide the optimal level of nutrients.

A smoothie is smooth because the blender smashes the structure of food into tiny bits, breaking up the fibre of the cell walls and liberating natural sugars into the emulsion. This freeing up of sugars may cause the body to handle them in a less health supporting way, more like refined sugars, such as fructose, rather than the slow release sugars in whole fruits and vegetables. Digestion is a complex process, only partially understood, and altering one part of the process, such as chewing and the action of saliva, is bound have unexpected repercussions. One example of this complexity is the postulated nitric oxide enhancing effect of chewing nitrate containing vegetables which may improve endothelial function.

So, enjoy a smoothie occasionally as a treat or short-term therapy, but otherwise….. CHEW YOUR FOOD.

Resources

• Blending Up the Smoothie Controversy – Dr Linda Carney
• Dr Esselstyn FAQ on smoothies 
• Are Smoothies Good or Bad? – Thomas Campbell, MD
• To smoothie or not to smoothie? The skinny on blending your fruits and greens – Lani Muelrath
• Why I Stopped Drinking Green Smoothies – Happy Herbivore (Lindsay Nixon)
• The Downside of Green Smoothies – (6 min. video) Dr Michael Greger. See also the other 4 videos of the series.

Jeff Novick, RD answers questions about juicing on the McDougall discussion forum:

• Fruit juice: Just another sugary drink?
• Green smoothies
• Calories, Calorie Density, Fiber, Blending and Juicing
• Cooking vs blending

Page last updated 1 November 2016