They're quick, often delicious and sometimes healthy. But it all depends what goes in the blender. Claire Turnbull on how to build (and buy) a better smoothie.
Smoothies have become a staple in cafés, gyms, supermarkets, and home kitchens, often seen as the easy, “healthy” option when life is busy. Which, sometimes they are. A well-made smoothie can be a brilliant way to get a boost of nutrients, especially when you’re short on time or need something on the go. But they’re not automatically a win. Some smoothies are more like a drinkable dessert and can leave you feeling hungry again not long after.
The difference comes down to what goes into the smoothie and how much of it you have.
The up sides
First up, smoothies are super easy to make; you can mix up the recipes, and they are a great way to use fruit that is getting a bit past it. Secondly, being portable, they really can be a help when you’re needing something to grab-and-go or sip as you do other things.
At our place, at least once a week, they're the go-to for my kids after school and on the way to sports and other activities. I have two boys heading rapidly towards their teens (and already eating me out of house and home) and the smoothie option helps me get a good balance of nutrition, as well as fluid into them on busy days.
Personally, I'll very occasionally have a smoothie for breakfast. More often, I'll opt for one in the afternoon if I'm having a really hungry day, dinner feels a long way off, and chopped up veg just isn’t going to cut it! This is maybe a couple of times a month.
I know I'm not the only one who falls into the snacky-afternoon-trap as it often comes up with people I support who, after a busy day, try to hold out until dinner but end up picking and nibbling on a handful of this and that. If this sounds like you too, it really is better off actually committing to having something like a nutritious smoothie, rather than eating what amounts to more than a meal's worth of calories, with unsatisfying little bites of crackers on cheese and other random bits and bobs.
Smoothies are also helpful for those who know they operate better having some food in the morning but often don’t feel like eating. They can also be useful for people with low appetites and those who struggle to gain weight, as well as after exercise to easily get in carbohydrates, protein and fluid to support recovery.
So, they definitely have a place.
The downsides
One of the biggest things to be mindful of with smoothies is that they don’t require you to chew. While this can be helpful when you are busy and, on the go, it can also sometimes be a problem. Chewing helps signal to your brain that you are eating and gives your body time to register fullness, which helps regulate your appetite.
Smoothies therefore can make it easy to end up having more energy (calories) than if you ate the separate ingredients and had to chew them.
It is not uncommon for me to come across people who put two or more servings (handfuls) of fruit along with juice, yoghurt, honey, seeds and a few extras together, and end up with a smoothie that is probably double what they needed energy-wise for their breakfast or a snack.
For busy people (like my boys) whose energy requirements are higher than some adults, these smoothies can be a super helpful part of their day. But for people who are struggling with their jeans being tighter than they would like or who have health conditions related to their weight, smoothies have the potential to work against their goals.
Another consideration is that by blending up the ingredients, you are breaking down the structure of plant foods (like fruits, vegetables, oats, nuts and seeds). This means the fibre is still there, but it’s less intact, and the sugars are more readily available, meaning they can be absorbed more quickly. Because of this, smoothies, while easy to consume quickly, may not keep you as full as eating the same foods whole.
So, while a smoothie can be a great option, in many cases you may feel more satisfied eating foods like pineapple, a pear or berries whole. This is one reason why it’s worth being mindful about having smoothies every day.
Smoothies can also be a vehicle for a lot of added sugar – honey and maple syrup being common ones used in the home, as well as the many syrups that are often used when you get a smoothie out in a café.
In the supermarket, there are also many brands of smoothies which are really, basically, just like juice with more texture and don’t have the benefits of protein and healthy fats that homemade smoothies can have.
Fruit juice and some smoothies can contribute to what are called "free sugars", which the World Health Organisation recommends limiting to less than 10% of total daily energy intake (around 50g for many adults), and ideally below 5% (around 25g) for additional health benefits. Just 250mls (1 cup) of one of these tropical smoothies, for example, contains around 28g sugar.
How to build a better smoothie
Here is the combo I suggest for most people when making a smoothie that is balanced: Liquid + fruit + veg + protein + optional extras.
1. Liquid
What you use as your base makes a big difference. Good options include cow or soy milk (which is nutritionally comparable to cow's milk). You can also use plant-based milks like oat, rice and almond, but do be aware they are often lower in protein and only have a decent amount of calcium in them if it is added.
Unsweetened yoghurt with a splash of milk or water is another option. Where people often come unstuck is using fruit juice as the base which raises the sugar content of the smoothie substantially. If you want fruit in your smoothie, use whole fruit.
2. Fruit
For many people, two servings (handfuls) of fruit a day – be it fresh, frozen or canned – is a good rough guide (or more for those who are more active). A serving as classified by the Ministry of Health here in New Zealand is roughly 150g, that equates to a medium banana plus two small kiwifruit or 1 cup frozen berries.
Beyond that, it is best to have more veggies. Not because fruit is "bad" by any means, but just because many people who eat a lot of fruit then fall short on other things like veggies, protein-rich foods or wholegrains, for example.
For smoothies, I would encourage you to think about keeping to one serve, maybe two if your smoothies fit into the category of fuel for recovery after a big workout session, or for busy active teens.
Dried fruit? It is fine to add the odd date into your smoothie for a bit of sweetness but do remember dried fruit is concentrated in sugar and easy to overdo, so keep portions small.
3. Veggies
Adding some veggies into your smoothie is one of the easiest wins! They add extra fibre, vitamins, minerals as well as volume without really pushing up the sugar content.
Good options to try including spinach (fresh or frozen), kale, frozen cauliflower, courgette, carrot, cooked beetroot (not in vinegar!), cooked pumpkin or even frozen peas.
It might sound a bit odd, but once blended with the right ingredients, you often won’t taste them much at all. I have lots of recipes on my website if you want to give them a try.
4. Protein
Protein helps keep you full, supports muscle maintenance and repair, and can help with more stable energy levels across the day.
You don’t need anything that is too fancy here. Your milk or yoghurt base might be enough, but if you are looking for extra to keep you feeling fuller, help you recover from a workout or hit the midlife protein goals perimenopausal women like myself are aiming for, then you can try adding: unsweetened yoghurt (regular or high protein), cottage cheese, peanut butter (or tahini if you can’t have nuts), silken tofu which is nice and soft (and honestly, you won’t even taste) or, if your blender is up to it, whole nuts and seeds.
You can also add a protein powder, or another easy, affordable option is adding a spoonful of trim milk powder for a bit of a protein boost. Something I often recommend for active teens. I go for trim as it is slightly higher in protein than the blue top with that being the goal.
5. Extras
There’s no shortage of powders, boosters and “superfood” add-ins out there, but sometimes the simplest things are the best. I like to add a tablespoon of rolled oats and a tablespoon of either chia seeds, flaxseeds or hemp seeds for extra fibre and some healthy fats. Cinnamon, cocoa, or cacao are also good for flavour.
Buying a smoothie: what to watch for
Not all smoothies you buy are created equal. Some cafés may offer options similar to what you might make at home based on milk and yoghurt with real fruit, which can be relatively balanced. Others are mostly fruit juice and sometimes also have added ice-cream, frozen yoghurt or added syrups.
Also, be very mindful about getting caught in the upsizing trap. Some chains offer multiple sizes where it feels like good value to spend an extra couple of dollars to get more. But some of those larger sized smoothies can contain several hundred calories (sometimes around 700+ kcal, roughly equivalent to about 7–9 slices of bread depending on the type) and a significant amount – sometimes more than 80g(!) – of sugar.
So, while the pricing structure might seem to make sense, it's not the kind of "good deal" your body actually needs. There's a cost there on both your wallet and your wellbeing, however tempting and logical a size up seems!
Claire Turnbull is a registered nutritionist with an honours degree in dietetics, a wellbeing educator and author.
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