Do Smoothie Diets Work? – Read this before trying

Sunday 26th May 2024

They’re delicious, depending on the ingredients anyway. They’re often low calorie but still full of nutrients. The colors are often exciting.

Who doesn’t like a pink or purple smoothie? Happy yellow, lively orange? I always give myself an imaginary pat on the back when I’ve had a green smoothie.

I just feel like I’ve done something amazing for my health whenever I have a green smoothie.

So, the question on your mind today is: Do smoothie diets work?

Given some of the benefits I listed above, you may think the answer is a straight up yes.

But, the truth is, it depends on the type of smoothies you have and the types of other foods you may be eating.

I’ll be looking at an all smoothie diet, smoothie and solid food diet, the benefits, the nasties, and everything in between.


The Short Answer: Do Smoothie Diets Really Work?

Yes, and when done correctly, they even have a host of health benefits along with weight loss if that’s what you’re after.

In terms of smoothie only diets, you will need to make sure that you include fat and protein sources too. And make sure you get some carbs in too along with a wide variety of fruit and vegetables.

I have a Nutribullet. I love it because it retains all the fiber of the produce too instead of spitting it out one side like juicers do.

Smoothies are all the result of blending as opposed to juicing.

The added benefit of retaining the pulp and fiber of the produce is part of why smoothies are great.

You can easily blend in other helpful ingredients too to make healthy and delicious smoothies.

If you can’t consume fiber, juicing may be more what you’re looking for.

Here are some quick tips for well-rounded smoothies:


Consume The Rainbow

fruits and veg for smoothie diet

This you can do by making all sorts of smoothies that include greens, orange veggies, yellow veggies, purple veggies, etc. You can add fruit for some sweetness.

My secret weapon for making green smoothies taste good? Bananas and vanilla extract. I also like kale in my green smoothies. I can see some of you pulling faces already.

But, don’t knock it till you try it. To be fair, I am not a kale person. It’s not the taste. It’s that it smells like someone farted in my fridge every time I open it to get something.

Apologies for the crass statement. But honestly, that is how I feel and those are the words that do it justice.

I don’t generally do raw broccoli, or even cooked broccoli in my smoothies either.

But if you are going smoothie only diet, consider at least lightly steamed or blanched broccoli to get in some cruciferous vegetables.

Aside from giving your body what it needs to detox, another huge benefit is that these veggies fight against cancer.

Arugula is also a good cruciferous veggie that works well in smoothies.

But note, that if you struggle with thyroid issues, you should only consume cruciferous veggies in moderation.



Fruit is a good source of carbs in a smoothie.

I don’t limit my fruit intake, and unless you’re on a ketogenic diet or diabetic, you don’t need to either. Even 20 servings of fruit per day was found to be safe for most people.

If you are diabetic, you may need to limit your fruit intake. You should be able to include more fruit when drinking smoothies as opposed to juicing.



You need fat to absorb the fat-soluble vitamins A, D, E and K. These nutrients are present in produce like carrots, leafy greens, nuts, and seeds.

You can add coconut oil or MCT, ground flax seeds, flax oil, hemp oil, nuts, seeds, or even olive oil for some fat.

Seed sources of fat have the added benefit of fiber. Flax seeds have a thickening effect too as do soaked chia seeds.



In addition to nuts and seeds, a good way to ramp up the protein content of your smoothies is to add protein powder.

Try whey protein if you don’t mind animal products. If you have a sensitive digestive system, try pea protein.

Otherwise, pick your favorite protein powder.

Sugar-free or low sugar options are best. Especially when they use natural sugar replacements such as stevia, monk fruit, date sugar, or sugar alcohols like xylitol.

Meal replacement powders also often contain a good amount of protein and added nutrients. They also go well with fruit and even veggies.

Milk, whether dairy or plant-based also offers some protein depending on the type of milk.

Yogurt is also a delicious addition to smoothies that is full of protein.


The Long Answer: Do Smoothie Diets Really Work

Everything you wanted to know about smoothies, particularly for weight loss and wellness in general will be answered here.

So, What Exactly is a Smoothie?

Smoothies are thick, often creamy beverages that are made from fruit, vegetables, milk, fruit juice, water, nuts, seeds, oils, protein powders, healthy algae, healthy grasses, etc.

They are made using a blender.

Juicing Has Been Around for Centuries And Smoothies Still Young In Comparison

Until I did my research for this article, I thought that juicing at home anyway, was a fairly new concept, maybe only a century or two old.

But, according to Dummies, there was mention of an attempt at juicing in 150 B.C already. People noticed the benefits of fruit and vegetables and likely tried to harness it, much like we do today.

Smoothies caught on a much later.

In 1922, the first blender was produced for making milkshakes. But by 1932, the creator of the blender received the patent for creating a blender to liquify fruits and vegetables too.

It seems that smoothies as we know them today only became popular in the 1960s really.


The Benefits of Smoothies

Weight Loss

Whether you are on an all smoothie diet or just replace one or two meals with smoothies, you can lose weight.

Just note that if you construct a smoothie in a way that it can be used as a meal replacement, they will be higher in calories than you might think.

For example, I created my favorite smoothies in My Fitness Pal. The calorie content is as follows:

  • My banana chocolate soy protein smoothie: 205 calories
  • My Carrot and Orange smoothie: 104 calories

I would need to add some protein on the side if I had my carrot and orange smoothie, but for the banana chocolate smoothie, I am happy to consume them as an actual standalone meal.

You don’t want to go too low in calories. Women generally shouldn’t consume less than 1200 calories. You risk becoming nutrient deficient and slowing your metabolism.

So don’t be afraid to make a robust smoothie, but try to keep them at 150 to 400 calories as meal replacements.


Increases Your Servings of Fruit and Vegetables

The average American doesn’t consume the recommended minimum of five servings of fruit and veggies per day.

Even more shocking is a survey conducted by OnePoll found that around a quarter of Americans have never eaten a vegetable.

Smoothies to the rescue!

If you don’t like eating fruit and vegetables, smoothies are a great way to get them down fast or mask the flavor a bit.

Adding ingredients like cocoa powder or vanilla protein powder can make all the difference.

Remember my trick with the green smoothies? Yes, vanilla extract does have some benefits including antioxidants and very small amounts of magnesium and potassium.

Just steer clear of it if you are trying to stay away from alcohol completely.



As you may have gathered by now, the fiber content is retained when the edible parts of the fruit or vegetable is blended.

That goes for nuts and seeds too.

This is another nutrient that many people need more of. Aim for at least 25g of fiber per day.


The Downsides

Smoothies can be Nutritious and Delicious Calorie Bombs

Some smoothies can be surprisingly high in calories.

There is something to be said for wholefoods. You don’t need to be as careful calorie-wise, because especially whole plant foods are low in calories.

But still, it’s easy for the calorie content to be high in a smoothie. I got such a shock when I saw how many calories my banana, apple, spinach, and pea protein smoothie has.

356 calories to be exact.

During lockdown, I gained a bit of weight along with many other people.

Half the issue was junk that I was eating. The other part was a lack of exercise.

The rest of it was thinking, well this smoothie is a nice healthy snack rather than a meal. Oops.

It contains:

  • A handful of English spinach
  • 1 medium to large banana (slightly unripe or slightly ripe)
  • 1 small to medium red apple
  • 2 tablespoons of pea protein isolate
  • A tablespoon of ground flax seed
  • Some cinnamon (I like a lot, so around half a teaspoon of Ceylon cinnamon)
  • About 1/8 of a teaspoon of vanilla extract
  • ½ to ¾ of a cup of unsweetened almond milk

And bam! About 356 calories. Sneaky.

The protein powder, banana, and to a lesser extent, the ground flaxseed powder are the main culprits here.

To be fair though, I did feel quite full after, I should have guessed.

If you add in a tablespoon of oil as your fat you’re looking at around 120 calories.  A cup of dairy milk is also anything from 87 calories (skim milk) to over 140 calories per cup.


Sugar Content can be High

If you like sweetening your smoothies with sugar or syrup, you may end up pushing the sugar content up quite a bit.

There is already sugar in your smoothie, particularly if you added fruit.

Again, eating lots of fruit isn’t a bad thing.

Blending the fruit ensures that you still have the fiber there, but it’s still not quite like eating an actual piece of fruit. Although it’s better than juicing.

Adding sugar to your smoothie is unnecessary.  Women should consume no more than 6 teaspoons of added sugar per day.

Added sugar includes the sugar they put in processed foods, the sugar you add to your coffee or tea, the sugar in your Star Bucks frappé, and even fruit juice.

Again, be cautious with adding fruit juice to your smoothies too. Fruit juice has had most of the fiber and pulp removed leaving a whole lot of sugar behind that spikes your blood sugar levels.

Rather go for xylitol, stevia, erythritol, or just stick to sweetening with fruit.


A Smoothie Diet can be Restrictive

If you only make the same smoothies over and over without changing the fruit and veggies up, you may end up lacking certain nutrients.

Also, if you like to drink a lot of green smoothies, note that constantly consuming greens high in oxalates may cause kidney stones in some people.

Use high oxalate foods like spinach and beetroot greens once or twice a week. Choose low to medium oxalate greens like kale, broccoli, arugula, and various types of lettuce the rest of the time.

Iron absorption is also inhibited by a long list of things like calcium, oxalates, polyphenols, and phytic acid.

These things are not bad for you. In fact, they are very necessary for your health.

Don’t stop eating the foods that contain them which is mostly dark leafy greens, beans, dark red fruit and veggies, and purple fruit and veggies.

But you should add fruit and veggies that are high in vitamin C to aid absorption of the iron. These include oranges, broccoli, kiwis, and strawberries.

And be sure to eat a proper wholefood meal that doesn’t contain dairy and steer clear of tea and coffee around meal times as the polyphenols and caffeine interfere with nutrient absorption.


Can You Lose Weight Drinking Fruit Smoothies?

Yes, you can. Again, you will need to make sure you don’t go overboard with the calories.

So bear in mind that when you add milk, oils, nuts, and seeds, you are possibly adding high-calorie ingredients.

Remember, if you are drinking one or two a day as meal replacements, 200-400 calories per smoothie is not a bad thing.

You will need more calories per smoothie, or 4-5 smoothies a day if you are on a smoothie only diet if they are under 400 calories.

But be sure to include other meals that include cruciferous veggies and dark leafy greens too if you are going to use fruit smoothies as meal replacements for more than a week.

These foods contain important nutrients for overall health.


How Long can You do an All Smoothie Diet?

This isn’t a very sustainable diet long-term. Many people who go for a long-ish all smoothie diet do it for around 21 days.

But this is difficult for a lot of people. You have to seriously like smoothies and not care about solid foods very much.

You also need to construct your smoothies properly and vary the ingredients regularly to make sure that you get all the nutrition you need.

If you aren’t willing to do that, I would limit the diet to a week.

In my opinion, it’s best to rather take the route of one to two smoothies a day and solid food for at least one meal and any snacks too.

That will enable you to still enjoy food with friends and family. And if you stick to clean eating, that is, no junk or processed food for 80% of the time, you will still see the benefits.

If you struggle with staying away from “naughty” foods, incorporating a cheat meal can help with that feeling of deprivation and bolster your self-control a little bit.


Is the Smoothie Trend Here to Stay?

All trends come and go. That’s easy to see in the world of nutrition. There are so many diets floating around.

But smoothies are still very popular. Considering that they have been around since the 60s, I don’t see it letting up completely any time soon. There’s a lot to enjoy about smoothies.

Science backs up the health benefits of smoothies. Do green smoothies work? Will you lose weight on the smoothie diet? Yes, you will. But include protein and make sure you get enough calories.

Or else you will just put all the weight back on once you go back to eating regular food. Or lose muscle while you lose weight.

The answer as with any diet full of healthy foods is if you do it properly and in a healthy manner, yes. You will reap benefits, not only in terms of weight loss but for your overall health too.

Find what works for you. If smoothies aren’t for you but you still want something liquid, try souping.


Some Final Tips

  • Don’t add the pits of stone fruit like peaches and apricots to your smoothie as they are poisonous.
  • Avoid apple pips since consuming too many of them is also dangerous to your health.
  • For any veggies that need to be cooked, steam them first.
  • Look for recipes for lots of ideas and guidelines on how to prepare the fruits and vegetables.
  • Always make sure what you can and can’t put in your blender. Some don’t handle heat well and some can’t handle hard things like ice or frozen fruit and veggies.

Smoothie Diet Program

If you’re looking for a structured program I would 100% recommend trying the smoothie diet.

It is full of healthy ingredients and easy to make smoothies.  You can also have all the recipes downloaded to your phone.

Let me know your results in the comments if you try 🙂

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