Medical disclaimer: This article is for general information and isn’t medical advice; speak to a GP or dietitian about your individual needs.
Smoothies can be genuinely healthy — or they can be a large glass of sugar. The difference comes down to what’s in them. A smoothie built around whole fruit, vegetables, protein, and fibre is a nutritious, satisfying option. One made mostly of fruit juice and sweeteners is essentially a dessert. This guide will help you tell the difference.
Are smoothies healthy?
The honest answer is: it depends what’s in them.
Smoothies have attracted a lot of conflicting press — hailed as a quick route to your five-a-day one year, then condemned for their sugar content the next. Both camps have a point. The word “smoothie” covers an enormous range of drinks, from a handful of berries blended with oat milk and a scoop of protein to a litre of mango juice with honey and dried fruit. Treating them as a single category doesn’t help anyone.
What’s clear is that whole fruit and vegetables are good for you. Blending them doesn’t change the fundamental nutritional value of the ingredients — it just changes the texture and, in some cases, how quickly those nutrients enter the bloodstream. The fibre in whole blended fruit is largely preserved (unlike juice, where pressing removes most of it). The vitamins are largely retained. The antioxidants are still present.
Where smoothies can go wrong is portion size, sugar content, and the absence of anything to slow down that sugar absorption — protein, fat, or fibre. A well-built smoothie accounts for all of these.
Sugar in smoothies: the honest truth
This is the part most smoothie brands would rather not talk about. We will.
Fruit contains natural sugar — fructose — and blending it concentrates it in ways that are worth being aware of. A single banana contains around 14g of sugar. A cup of mango adds another 23g or so. A cup of pineapple, 16g. Add them all together in a large smoothie and you have a drink containing 50g+ of natural sugar, which is more than most people would choose if they were thinking about it.
The NHS counts smoothies as a maximum of one of your five-a-day, regardless of how many different fruits are included. That’s because, while the fibre is mostly present, the natural sugars are easily consumed in quantity in liquid form. You can drink a smoothie faster than you’d eat the equivalent whole fruit, and liquid calories don’t always produce the same satiety signals.
None of this means fruit is bad for you. It isn’t. The NHS continues to recommend fruit as part of a balanced diet, and fruit-based smoothies contain vitamins, minerals, and antioxidants that most of us genuinely don’t get enough of. But context matters. A 500ml smoothie made of five different fruits is not five servings of fruit — it’s one, and it contains a considerable amount of natural sugar in a concentrated, fast-absorbing form.
The practical upshot: pair fruit with protein and fat (which slow sugar absorption), keep portions sensible, and be honest about what else you’re eating and drinking that day. That’s it. No need to be frightened of a banana.
The healthiest smoothie formula: five principles
After a lot of thought about what makes a smoothie actually satisfying and nutritious rather than just nice-tasting, we’ve landed on five principles.
1. Start with whole fruit, not juice.
Juice removes most of the fibre. Whole blended fruit preserves it. Fibre slows sugar absorption, feeds beneficial gut bacteria, and contributes to satiety. Always blend the fruit itself rather than using fruit juice as your liquid base. We use water, oat milk, or coconut milk.
2. Add protein.
Protein is the most satiating macronutrient. Without it, a fruit-only smoothie will digest quickly and leave you hungry within an hour. A scoop of protein powder, a handful of nuts or nut butter, some Greek yoghurt, or oat milk all contribute protein. At Framberry, we offer protein booster add-ins to any smoothie.
3. Include something with fat.
Fat — particularly from nuts, seeds, or avocado — further slows digestion and contributes to lasting satiety. It also helps with the absorption of fat-soluble vitamins like A, D, E, and K. A tablespoon of almond butter or flaxseed achieves this without dramatically changing the flavour.
4. Watch the volume.
A sensible serving is around 300–400ml. Larger volumes are increasingly calorie-dense and more sugar than most people need in a single sitting, regardless of how natural the ingredients are.
5. Don’t add unnecessary extras.
Agave syrup, honey, flavoured yoghurts, chocolate sauce, and dried fruit all add significant sugar without adding much nutritional value that isn’t already in the fruit. Build flavour through fruit variety, spice (cinnamon, ginger), or a small amount of vanilla extract rather than sweeteners.
Protein and post-workout smoothies
Smoothies are particularly well-suited to the post-workout window, when your body is primed to use carbohydrates and protein for muscle recovery.
After exercise, your muscles are receptive to glycogen replenishment, and a combination of fast-absorbing carbohydrates (fruit is useful here) with adequate protein supports the repair process. Most sports nutrition guidance suggests 20–40g of protein in the two hours after training, alongside sufficient carbohydrates. The exact numbers vary depending on your body weight, training intensity, and goals — but the principle is consistent.
A well-built post-workout smoothie achieves this neatly: a banana and a handful of berries for carbohydrates, protein powder or nut butter for protein, and a base of oat or coconut milk. At Framberry, you can build your own smoothie with protein and superfood boosters added to any of our base blends. We use banana, mango, strawberry, raspberry, blueberry, cherry, and kiwi across our menu, so the combinations are flexible.
The timing matters less than the popular idea of a “30-minute anabolic window” once suggested. More recent research suggests the window is broader — somewhere in the two-to-three hours after training. But getting something nutritious in you after a run or a class is always a good idea, and a smoothie is one of the easier ways to do it when you don’t feel like cooking.
Smoothies for weight loss
Let’s be straightforward about this. A smoothie is not a weight-loss product. No food is. But smoothies can be a useful tool within an approach to eating that works for you.
The appeal is practical: a well-built smoothie is portable, quick to prepare, and can deliver a reasonable amount of protein, fibre, and micronutrients in a format that’s easy to consume when you’re busy. If it replaces a skipped breakfast or a less nutritious option, that’s a genuine win.
Where smoothies go wrong as part of a weight-conscious approach is when they’re used to supplement rather than replace meals. A 500ml fruit smoothie alongside a full breakfast adds several hundred calories and a significant sugar load. As a breakfast in itself, built with protein and fat, it’s a different proposition.
The most useful thing you can do is be honest about what your smoothie actually contains. Use a smoothie with fruit, protein, and unsweetened milk as a meal replacement or post-workout option. Avoid the extras — syrups, sweetened yoghurts, excessive dried fruit — that turn a nutritious drink into something closer to a dessert. And don’t drink them alongside meals unless you’ve accounted for the calories.
None of this requires counting every gram or treating food as a source of anxiety. It just requires a little honesty about what you’re putting in the blender.
How to build a smoothie at home
You don’t need a high-powered blender or a wall of superfood powders. Here’s a reliable formula for a satisfying, nutritious smoothie.
Base (pick one):
– 200ml oat milk (naturally creamy, low in sugar)
– 200ml coconut milk (from a carton, not a tin — lower fat)
– 200ml water (if you want a lighter result)
Fruit (aim for 150–200g total):
– Banana + berries is the classic combination — the banana provides texture and sweetness, the berries provide flavour and antioxidants
– Mango + pineapple for a tropical profile
– Kiwi + raspberry for something tart
Protein:
– 1 scoop protein powder (whey or plant-based)
– 2 tablespoons almond butter
– 150g natural yoghurt
Optional boosters:
– 1 tablespoon ground flaxseed (fibre, omega-3)
– 1 teaspoon spirulina (a source of plant protein and B vitamins — some studies suggest potential benefits for energy, though evidence is mixed)
– A small handful of spinach (largely flavour-neutral; adds iron, folate, vitamin K)
– Half a teaspoon of cinnamon (warming, and some studies suggest it may support blood glucose management)
Method: combine everything in a blender, blend until smooth. Taste. Adjust sweetness with a small amount of additional fruit rather than sugar.
Try ours in London
At Framberry, our smoothies are built around fresh, real ingredients. We use whole fruit — banana, mango, strawberry, raspberry, blueberry, cherry, kiwi — with oat milk as the default base, and we offer protein and superfood boosters for add. Nothing is pre-made or shelf-stable; every smoothie is built to order.
We’ve also designed the menu to work for as many people as possible. Most of our smoothies are vegan, all are non-alcoholic, and the whole menu is halal- and kosher-friendly. Families are welcome — we do a babychino for little ones and a puppychino for dogs, both free with an adult drink.
We’re opening in London in 2027. Join the list to find out where.
Frequently asked questions
Do smoothies count as one of your five-a-day?
According to NHS guidance, a smoothie counts as a maximum of one of your five-a-day, regardless of how many different fruits or vegetables it contains. This is because the natural sugars in fruit become more concentrated in smoothie form and are consumed more quickly than whole fruit.
Are smoothies high in sugar?
They can be, yes. A smoothie made from several pieces of fruit can contain 40–60g of natural sugar or more. The sugar in whole fruit comes packaged with fibre, vitamins, and antioxidants, which is different from added sugar — but it’s still worth being aware of the quantity, especially if you’re having a large serving or drinking smoothies frequently alongside other meals.
What’s the best protein for a smoothie?
It depends on your preferences and dietary requirements. Whey protein powder is fast-absorbing and widely used. Plant-based proteins (pea, hemp, brown rice) work well for vegan diets. Nut butters — almond or peanut — add protein along with fat and flavour. Natural yoghurt is a good option if you want something that doesn’t require a specialist product.
Are smoothies good after a workout?
A smoothie combining carbohydrates from fruit and adequate protein (20–40g depending on your body weight and training) is a practical post-workout option. The carbohydrates help replenish glycogen stores; the protein supports muscle repair. Build in protein deliberately — a fruit-only smoothie won’t provide enough.
Can children drink smoothies?
Yes, in appropriate portions. The NHS recommends limiting fruit juice and smoothies to 150ml per day for children, served at mealtimes to reduce the impact on teeth. At Framberry, we offer a babychino (warm frothed milk, caffeine-free) for younger children, and our smoothies can be made in smaller portions.
Our smoothies are built from whole fruit, to order, with nothing added that shouldn’t be there. Framberry is opening in London in 2027. Join the list to find out where.