What is the smoothie diet for 21 days?

The smoothie diet is a type of liquid diet that involves replacing meals with smoothies made from fruits, vegetables, protein powders, and other ingredients. It has become a popular way to lose weight and detoxify the body over a short period of time, usually lasting about 3 weeks or 21 days.

The smoothie diet claims to offer a number of benefits including:

  • Rapid weight loss – People report losing anywhere from 10-15 pounds in 21 days
  • Body detoxification – The nutrients in smoothies help remove toxins
  • Reduced cravings for unhealthy foods – Smoothies are nourishing and can control cravings
  • Increased energy – Blending breaks down fiber, making nutrients easily digestible

The smoothie diet involves replacing solid food with smoothies made from fruits, vegetables, leafy greens, nuts, seeds, nut butters, protein powders, yogurt and milk. Meal replacement shakes can also be used if they are higher in nutrients and lower in sugars.

Water intake is also increased to help flush out toxins. Many versions of the smoothie diet allow one solid meal per day, usually dinner. Portion sizes for solid foods are kept smaller.

Rules of the 21 Day Smoothie Diet

Here are the basic rules to follow for the 21 day smoothie diet:

  • Drink only smoothies and water for breakfast and lunch
  • Have 1 healthy solid meal for dinner
  • Make smoothies with at least 2 servings of fruits and vegetables
  • Include lean protein in smoothies or meal
  • Avoid added sugars, sweeteners and ice cream
  • Make only fresh smoothies, no store-bought
  • Drink water throughout the day
  • Take a multivitamin to fill any nutritional gaps
  • No snacking or desserts
  • No alcohol

The basic smoothie ingredients for the 21 day diet should include:

  • Leafy greens – spinach, kale, swiss chard, collards
  • Fruits – berries, banana, mango, pineapple, apple, oranges
  • Vegetables – carrots, beetroot, tomatoes, avocado
  • Nuts and seeds
  • Nut butters – almond, peanut, cashew
  • Ground flax or chia seeds
  • Protein – whey powder, Greek yogurt, cottage cheese
  • Milk – almond, soy, skim or low fat dairy
  • Water and ice

Sample 21 Day Smoothie Diet Meal Plan

Here is an example of what a daily meal plan may look like on the 21 day smoothie diet:

Breakfast – Green smoothie

  • 1 cup kale or spinach
  • 1 banana
  • 1 cup milk of choice
  • 2 tbsp ground flax or chia seeds
  • 1 scoop protein powder
  • 1 cup water
  • Blend all ingredients together

Lunch – Fruit smoothie

  • 1 cup strawberries
  • 1 cup yogurt
  • 1⁄2 cup orange juice
  • 1⁄4 avocado
  • 2 tbsp nut butter
  • 1 cup ice
  • Blend all ingredients together

Dinner – Salad with protein

  • 3 to 4 oz chicken or fish
  • Big salad with veggies
  • 1 tbsp salad dressing
  • Herbs, spices, lemon juice

You can swap out ingredients daily based on your preferences. Try to vary the fruits, vegetables, nuts and seeds to get a wide range of micronutrients.

Smoothie Diet Shopping List

When grocery shopping for the 21 day smoothie diet, you’ll want to stock up on:

  • Fresh and frozen fruits – berries, bananas, pineapple, apples
  • Fresh and frozen leafy greens – spinach, kale, swiss chard
  • Fresh vegetables – carrots, avocado, beets, tomatoes
  • Nuts and seeds – almonds, walnuts, chia, flaxseed
  • Nut butters – almond, peanut, cashew
  • Milk – skim, almond, soy, coconut
  • Yogurt – Greek, plain, low-fat
  • Protein powder – whey, plant-based
  • Water and ice
  • Ground herbs and spices
  • Chicken, fish, lean meats
  • Salad greens and vegetables

Be sure to have enough fruits, vegetables and smoothie ingredients on hand for at least 3 days before needing to re-stock. Buying in bulk can help reduce costs.

Benefits of the 21 Day Smoothie Diet

There are many benefits associated with following the smoothie diet for 21 days including:

Weight loss – By sticking to smoothies and one solid meal per day, you reduce daily calorie intake substantially which leads to weight loss. Smoothies keep you feeling fuller longer too.

Body cleansing – Fruits and veggies provide antioxidants and fiber that help remove toxins from the body.

More energy – Because the nutrients are easily digestible, your body can readily absorb them leading to an energy boost.

Clearer skin – Hydration from smoothies and water flush toxins from skin cells and reduce acne. The nutrients boost skin health.

Lower cholesterol – The fiber in smoothies can reduce LDL (bad) cholesterol levels.

Blood sugar control – Blending fruits and veggies allows for slower sugar absorption. The fiber helps regulate blood sugar as well.

Improved digestion – Fiber and probiotics from yogurt support digestive system health and can reduce bloating and gas.

Benefit Explanation
Weight loss Reduced calories from replacing meals with low calorie smoothies leads to weight loss over 21 days. Smoothies provide satiety.
Body cleansing Antioxidants and fiber in fruits/veggies help flush out toxins.
More energy The easily digestible nutrients in smoothies are readily absorbed and provide an energy boost.
Clearer skin Hydration and nutrients from smoothies improve skin health and acne.
Lower cholesterol Soluble fiber in smoothies reduces LDL (bad) cholesterol.
Blood sugar control The fiber slows down sugar absorption and improves blood sugar control.
Improved digestion Probiotics and fiber support digestive system health and reduce bloating.

Smoothie Diet Before and After Pictures

Most people who stick to the smoothie diet for 21 days experience impressive changes in their body including rapid weight loss.

Here are some before and after pictures from people who completed the 21 day smoothie diet:

As you can see, sticking to smoothies and one solid meal per day for 21 days can lead to a slimmer figure and reduction in belly fat. People look and feel lighter on their feet after completing the smoothie diet.

Smoothie Diet Expected Weight Loss

So how much weight can you expect to lose on the 21 day smoothie diet? Most people report losing anywhere from 10 to 15 pounds over the 3 week period. However, results can vary based on:

  • Caloric intake – Lower net calories will lead to faster weight loss.
  • Exercise – Adding exercise can help burn extra calories.
  • Body size – People who weigh more tend to lose more pounds than those closer to their ideal weight.
  • Strictness – Sticking closely to smoothies and meal plan maximizes weight loss.

While fast, it’s recommended only doing the smoothie diet for 21 days at a time. It’s not a sustainable long-term eating plan due to potential nutritional gaps. Periodic smoothie diets can be an effective way to reach weight loss goals though.

Smoothie Diet Side Effects

When making such a dramatic change to your diet, some side effects or detox symptoms are common when starting the 21 day smoothie diet including:

  • Headaches – From cutting out coffee, fat, sodium and calories
  • Fatigue & weakness – The initial rapid calorie reduction can lead to low energy
  • Nausea – Your body is adjusting to the liquid diet
  • Irritability – From restricting favorite foods and lowering blood sugar
  • Brain fog – Your body is accustomed to more calories
  • Dizziness – Be sure to include salt and eat if feeling light-headed
  • Sugar cravings – Your body wants quick energy from sugar

These symptoms are temporary and usually subside within the first 1 to 3 days on the diet as your body adjusts. Be sure to include lean protein and good fats in smoothies to help minimize side effects of lowered calories.

How to Start the Smoothie Diet

Here are some tips for starting and transitioning onto the 21 day smoothie diet:

  • Gradually cut back on caffeine, sugar and processed foods the week before
  • Stock up on smoothie ingredients and meal plan for the week
  • Get your mind ready for the changes you are about to make
  • Start by having a smoothie for breakfast day 1, smoothie for lunch day 2, until fully transitioned
  • Make larger smoothies to better manage hunger early on
  • Listen to your body regarding side effects and adjust accordingly
  • Drink lots of water, herbal tea and nibble on veggies if hungry
  • Plan your one daily solid meal wisely to include protein and fats
  • Supplement with vitamins, minerals or protein powder if needed

Easing into the smoothie diet and preparing mentally and physically will help you stick to the full 21 days and make the adjustment easier.

Smoothie Diet Tips

Here are some helpful tips to get the most out of the smoothie diet and make the 21 days easier:

  • Use frozen fruits and veggies to make smoothies cold and thick
  • Rotate your ingredients to get a variety of nutrients
  • Blend in coconut oil or avocado for healthy fats
  • Spice up smoothies with cinnamon, cocoa powder, vanilla
  • Try herbal teas if needing something warm
  • Drink each smoothie slowly and mindfully
  • Chew sugarfree gum or mint if craving sweets
  • Plan your shopping and prep smoothie ingredients in advance
  • Keep healthy snacks on hand – celery, carrots, hardboiled eggs
  • Stay motivated by tracking your weight loss and feeling results

Smoothie Diet vs. Juice Cleanse

How does the smoothie diet compare to a juicing cleanse? Here’s the breakdown:

Juice Cleanse Smoothie Diet
Ingredients Extracted juices from fruits/veggies Blended whole fruits, veggies, nuts, seeds
Fiber Removed during juicing Kept in soluble fiber form
Protein Very little Added protein powder or yogurt
Fat None Contains healthy fats
Calories Low, around 600-800 calories Higher, around 1,000-1,200 calories
Cost High for pressed juices Lower with homemade smoothies
Convenience Must make juices 2-3 times/day Make ahead in batches and store
Side effects Greater detox symptoms Less side effects

Smoothies tend to provide more balanced nutrition and are often easier to stick to than straight juices.


The smoothie diet involves replacing meals with blended smoothies made from whole fruits, veggies, nuts, seeds and proteins. It’s an effective way to lose weight, detoxify and add more nutrition in just 21 days. By planning smoothies and shopping accordingly, almost anyone can succeed and feel the benefits of this short term cleanse style diet. Just be sure to ease into and out of the diet, supplementing nutrients as needed. With some determination and preparation, you’ll be amazed by the results from just 21 days of smoothies.

Leave a Comment