The 21-Day Smoothie Diet is a weight loss plan touted as an easy and effective alternative to fad diets.

In fact, the creator of the plan claims that the diet is associated with a long list of benefits and can help improve sleep, keep your skin glowing, skyrocket energy levels, and increase weight loss almost instantly.

However, there are several serious downsides associated with this program, and it may do more harm than good in the long run when it comes to your health.

This article will take a closer look at the 21-Day Smoothie Diet, how it works, and some of the negative risks and side effects it may be associated with.

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The 21-Day Smoothie Diet is a weight loss plan developed by health coach Drew Sgoutas.

The plan involves swapping two of your meals each day with smoothies, and the principles of the program are outlined in the e-book, “The Smoothie Diet,” which is available online for $47.

The e-book includes 36 smoothie recipes, meal and snack ideas, shopping lists, weekly schedules, and tips for preparing the smoothies and maintaining weight loss long-term.

According to Sgoutas, the 3-week diet plan can help promote healthy eating, enhance immune function, detoxify the body, improve skin and gut health, and rev up energy levels.

Sgoutas also claims that the diet can boost weight loss. In fact, some testimonials displayed on the website claim that the plan led to up to 9 pounds (4 kg) of weight loss in just 3 days.


The 21-Day Smoothie Diet is a 3-week diet plan that involves replacing two meals per day with smoothies. The program claims to enhance immunity, boost energy levels, improve skin and gut health, and increase weight loss quickly.

The 21-Day Smoothie Diet involves replacing two of your meals each day with smoothies using the recipes found in the e-book.

There are 36 recipes provided in the book, created using ingredients like fruits, vegetables, nuts, seeds, and almond or coconut milk.

In addition to these two smoothies, the plan allows you to eat one solid meal per day and two healthy snacks.

Solid meals should consist mostly of whole foods, and snacks should be low in sugar and high in fiber, with around 150–200 calories per serving.

You are also allowed one cheat day per week where you don’t consume any smoothies, though meals should still consist mostly of whole, minimally processed foods.

Optionally, you can kick off the plan with a 3-day detox, which requires you to consume a smoothie in place of all three daily meals, with two healthy snacks in between.

According to the program’s website, the diet works by creating a calorie deficit, meaning that you are expending more calories than you consume each day.

The diet is also high in fiber and claims to help reset your taste buds to reduce sugar cravings.

The program is intended to be followed for 3 weeks but can be repeated as many times as needed until you ‘reach your goal weight.’


The 21-Day Smoothie creates a calorie deficit by replacing two of your meals with smoothies and eating one solid meal and two snacks per day. The plan should be followed for 3 weeks and can be repeated as many times as needed.

The 21-Day Smoothie Diet encourages nutrient-dense foods like fruits and vegetables while limiting processed ingredients.

Foods to eat

Most of the smoothie recipes included in the 3-week program consist of fruits, vegetables, nuts, and seeds, mixed with coconut milk, coconut water, or almond milk.

Additionally, the plan emphasizes whole, minimally processed foods for your remaining meals and snacks while following the diet.

Some specific examples of foods that are encouraged on the 21-Day Smoothie Diet:

  • Fruits:bananas, pears, apples, oranges, pineapples, raspberries, strawberries
  • Vegetables: spinach, kale, cauliflower, bell peppers, carrots, broccoli
  • Protein foods: chicken, turkey, salmon, eggs, legumes, Greek yogurt
  • Whole grains: brown rice, quinoa, oats, buckwheat, popcorn
  • Nuts and seeds: flaxseed, almonds, walnuts, chia seeds, nut butter
  • Beverages: almond milk, coconut milk, coconut water
  • Herbs and spices: vanilla extract, fresh ginger, parsley, mint, cinnamon
  • Other ingredients: unsweetened cocoa powder, unsweetened coconut flakes, vanilla extract, granola, honey

Foods to avoid

On the 21-Day Smoothie Diet, you should limit your intake of sugar-sweetened beverages and processed foods, including processed meat, refined grains, and fried foods.

Here are some examples of foods to limit or avoid while following the diet:

  • Processed meat: bacon, ham, pepperoni, cold cuts, salami
  • Refined grains: white rice, white pasta, white bread, tortillas
  • Fried foods: French fries, mozzarella sticks, donuts, fried chicken, fish sticks
  • Processed foods: convenience meals, cookies, chips, pretzels, baked goods
  • Sugar-sweetened beverages: soda, sweet tea, sports drinks, energy drinks

Whole, minimally processed foods are encouraged on the 21-Day Smoothie Diet, including fruits, vegetables, nuts, and seeds. Meanwhile, the plan limits processed foods such as refined grains, convenience meals, and sugary drinks.

According to the 21-Day Smoothie Diet creator, the plan provides a total of around 1,500 calories per day.

Consuming 1,500 calories per day will lead to weight loss for many people. However, this may vary based on many different factors, including your age, body size, health status, and activity level (1).

The diet also encourages a variety of nutrient-dense foods, like fruits, vegetables, nuts, and seeds, all of which are high in fiber.

Fiber moves through the digestive tract slowly, helping to keep you feeling fuller for longer, which could support weight loss (2, 3).

However, despite being low in calories and high in fiber, the 21-Day Smoothie is also very restrictive and can be difficult to follow.

Furthermore, research suggests that liquids, such as smoothies, are less filling than solid foods, meaning you may feel more hungry drinking mostly smoothies each day (4).

Not only that, but some studies show that weight loss programs that use meal replacements may be associated with a higher risk of weight regain once a typical diet is resumed (5, 6).

Therefore, while swapping some of your meals for smoothies may lead to short-term weight loss, it’s unlikely to be effective long-term.


The 21-Day Smoothie Diet is low in calories, plus high in fiber, which may lead to short-term weight loss. However, studies suggests that smoothies may be less filling than solid foods. Additionally, the plan may be difficult to follow and could increase the risk of weight regain.

In addition to being restrictive, unsustainable, and difficult to follow, the 21-Day Smoothie Diet may have several other downsides and side effects.

Increases risk of nutrient deficiencies

Eating just one solid meal per day and replacing your remaining two meals with smoothies may increase the risk of nutritional deficiencies.

Though the smoothie recipes recommended by this program contain nutrient-dense ingredients like fruits and veggies, they also omit or limit many of the foods typically included in a balanced meal, such as whole grains, healthy fats, and lean proteins.

Some are also low in protein. For example, the Green Detox smoothie — made with kale, coconut water, bananas, ginger, and lemon — contains less than 4 grams of protein per serving.

That makes it challenging to ensure you’re meeting your protein needs, negatively impacting tissue repair, muscle growth, immune function, and more (7).

Additionally, though the diet claims to provide around 1,500 calories per day, most the smoothie recipes are very low in calories and unlikely to provide enough calories to meet the needs of most healthy adults.

Consuming too few calories each day can slow your metabolism and cause serious negative side effects, including hunger, nausea, headaches, and fatigue (8, 9).

May be high in sugar

Many of the smoothies on the 21-Day Smoothie Diet contain multiple servings of fruits, including bananas, pineapples, peaches, and strawberries.

Some also contain other high sugar ingredients, such as honey or granola.

Though these ingredients can be enjoyed as part of a healthy, balanced diet, the high amounts included in this diet may not be suitable for everyone.

In particular, people with diabetes may need to monitor their intake of foods high in carbohydrates, such as fruit or honey, to prevent spikes in blood sugar levels (10).

Not based on evidence

One of the biggest flaws of the 21-Day Smoothie Diet is that there is no research to back it up.

While smoothies can be a great addition to a well-rounded diet, there’s no evidence to show that eating smoothies in place of other nutrient-dense foods can improve your skin, gut health, or immune function, as the diet claims.

Furthermore, the diet’s official website is filled with testimonials from customers claiming to lose large amounts of weight very quickly.

Not only is this unrealistic and unsustainable, but it could also be harmful to health (11).


The 21-Day Smoothie Diet is not based on evidence and may be associated with an increased risk of nutritional deficiencies. It is also relatively high in carbs and sugar.

The 21-Day Smoothie Diet is a 3-week weight loss plan that involves replacing some of your meals each day with smoothies.

Though the diet encourages many nutritious ingredients, it’s also restrictive, unsustainable, and very low in calories and protein, increasing the risk of nutritional deficiencies and other side effects.

Furthermore, it’s not backed by research and is high in carbs and sugar, which might not suit people with diabetes.

Instead of cycling through different fad diets to reach your goals, consider pairing a nutritious, well-rounded diet with a healthy lifestyle for best results.

That is more beneficial for weight management and overall health in the long run, and it’s also much more simple, sustainable, and effective.

Just one thing

Try this today: If you prefer a structured diet plan like the 21-Day Smoothie Diet, there are plenty of other options to help you reach your health goals. Check out this article for a list of the 9 best diet plans to consider.

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