AUTHORITY NUTRITION

Soylent Meal Replacements: Do They Work and Are They Safe?

Written by Helen West, RD on October 17, 2017

When you're busy, eating a healthy, balanced diet can seem difficult.

Cooking healthy food can be time-consuming, given that it takes time to plan, shop for, prepare and cook your food.

Depending on your income, tastes and cooking skills, it may also seem expensive, especially if a lot of food goes to waste.

In response to these issues, a group of engineers designed Soylent, a meal replacement drink.

Soylent claims to take the hassle out of maintaining a healthy diet by providing you with all the nutrition you need in a drink that’s cheap, tasty and easy to prepare.

This article takes a detailed look at Soylent meal replacements and explores whether they are a healthy alternative to eating regular food.

What Are Soylent Meal Replacements?

Replacement Shake

Soylent meal replacements were designed by a group of software engineers. They came up with the idea because they were frustrated by the amount of time they had to spend away from their work to cook and often found themselves reaching for cheap junk food to save time.

They set out to design a solution that solved their problems and provided people with a food source that was healthy, cheap, efficient and accessible. The result was Soylent.

The company claims you can swap your regular meals for Soylent meal replacement drinks and still get all the nutrients you need.

Each drink contains a source of fat, carbs, protein and fiber, in addition to a range of micronutrients, in 400 calories.

The drinks themselves come in three different forms:

  • Soylent drink: These are 14-ounce pre-mixed drinks, designed to replace one meal. Available in original and cacao flavors.
  • Soylent powder: Can be mixed with water to make a Soylent drink. Each pouch contains enough powder for five drinks. Available in original flavor.
  • Soylent cafe: These pre-mixed drinks are the same as the Soylent drink, but they contain added caffeine and L-carnitine. Available in coffiest, vanilla and chai flavors.

Drinking five Soylent drinks per day will provide 2,000 calories, around 15 grams of fiber and 100% of the daily recommended amount of essential micronutrients.

They cost $1.82–$3.25 USD per serving, with Soylent powder being the cheapest option.

However, there is a large do-it-yourself community linked to Soylent, with many people making their own recipes to improve upon the Soylent formula. If you take this approach, it will change the cost and nutritional makeup of Soylent.

Summary: Soylent drinks are complete meal replacements that provide you with carbs, fat, protein, fiber and essential micronutrients in a 400-calorie drink.

What's in a Soylent Drink?

Soylent drinks are a mixture of soy protein isolate, high oleic sunflower oil, isomaltulose and essential vitamins and minerals.

They’re nut-free, lactose-free and vegan.

Soy Protein

Soy protein isolate is a pure plant protein derived from soybeans.

It's a popular ingredient in the food industry since it’s a cheap, readily digestible source of protein that improves the texture of foods ().

Soy protein isolate is also a complete protein, meaning it contains all nine essential amino acids that your body needs to function ().

It also has a neutral taste, meaning it can be incorporated into foods easily without adding much flavor. Additionally, since it's plant-based, Soylent drinks are vegan.

One 400-calorie drink of Soylent contains 20 grams of protein, making it a high-protein drink.

High Oleic Sunflower Oil

The fat source in Soylent drinks is high oleic sunflower oil.

Sunflower oil is usually high in polyunsaturated fats. However, high oleic sunflower oil is derived from sunflower plants that have been bred to have a high concentration of oleic acid, a type of monounsaturated fatty acid.

Using this type of oil makes Soylent high in monounsaturated fats and also free of harmful trans fats.

Although Soylent doesn't make any health claims, using high oleic oils in place of unhealthy oils may help improve some risk factors for heart disease (, ).

Isomaltulose

Isomaltulose is a simple carbohydrate made up of two sugars — glucose and fructose.

It's found naturally in honey, but it can be produced on a commercial scale in large amounts from beet sugars.

Isomaltulose is used regularly in the food industry as a replacement for regular table sugar, also known as sucrose.

It’s made up of the same two sugars as table sugar, but they are bonded together differently, so it's digested more slowly. This means isomaltulose causes blood sugar levels to rise much more slowly than regular sugar does (, , ).

Vitamins and Minerals

Soylent is made up of nutrients and not whole foods. The vitamins and minerals essential for good health are added to each Soylent drink, with 20% of the recommended daily value for every nutrient in each serving.

Summary: Soylent drinks contain soy protein isolate, high oleic sunflower oil and isomaltulose. Each drink is also fortified, providing 20% of the recommended daily value of the essential vitamins and minerals.

Nutrition Breakdown

This is the nutrition breakdown for each of the Soylent meal replacement products.

Soylent Drink

Here are the nutrients you’ll find in a pre-made, 14-ounce (414-ml) Soylent drink:

  • Calories: 400
  • Fat: 21 grams
  • Carbs: 36 grams
  • Protein: 20 grams
  • Fiber: 3 grams
  • Vitamin D: 2 mcg
  • Iron: 4 mg
  • Calcium: 200 mg
  • Potassium: 700 mg
  • Vitamin A: 20% of the RDI
  • Vitamin K: 20% of the RDI
  • Riboflavin: 20% of the RDI
  • Vitamin B6: 20% of the RDI
  • Vitamin B12: 20% of the RDI
  • Choline: 20% of the RDI
  • Iodine: 20% of the RDI
  • Zinc: 20% of the RDI
  • Copper: 20% of the RDI
  • Chromium: 20% of the RDI
  • Pantothenic acid: 20% of the RDI
  • Vitamin C: 20% of the RDI
  • Vitamin E: 20% of the RDI
  • Thiamine: 20% of the RDI
  • Niacin: 20% of the RDI
  • Folic acid: 20% of the RDI
  • Biotin: 20% of the RDI
  • Magnesium: 20% of the RDI
  • Selenium: 20% of the RDI
  • Manganese: 20% of the RDI
  • Molybdenum: 20% of the RDI

Soylent Powder

This is the nutrition breakdown for one serving of Soylent powder:

  • Calories: 400
  • Fat: 21 grams
  • Carbs: 36 grams
  • Protein: 20 grams
  • Fiber: 5 grams

The only difference between the Soylent pre-made drink and powder is that the powder contains 2 more grams of fiber per serving.

The micronutrient content of the powder is the same as the pre-made drinks.

Soylent Cafe

In addition to nutrients, the Soylent cafe drinks also contain caffeine and L-theanine.

Caffeine is a commonly consumed stimulant that can increase your energy levels and help you feel less tired ().

L-theanine is an amino acid naturally found in green tea.

Caffeine and L-theanine have been shown to work together, so combining them may increase alertness and focus (, ).

Summary: Apart from a couple of minor differences, the drinks are the same. Soylent powder contains 2 more grams of fiber per serving than the pre-made drinks. Soylent cafe contains added caffeine and L-theanine.

Are Liquid Meal Replacements Healthy?

People use Soylent in a variety of ways.

Some people drink only Soylent to sustain them during certain periods of time, such as when they’re very busy at work or school. Others choose to replace occasional meals with the drink when it suits them.

Depending on your circumstances, there can be pros and cons to occasionally choosing liquid meals or switching to a liquid diet.

They May Make Your Diet More Nutritious

If you are short on time and often find yourself reaching for junk food, or if you are on a very low-calorie diet, switching to a meal replacement drink could improve your diet quality.

Meal replacement shakes like Soylent contain adequate levels of essential vitamins, minerals and fiber, which many people don't get enough of (, ).

This means that replacing a high-energy, nutrient-poor meal with a meal replacement shake could be better for your health.

However, the nutritional breakdown of meal replacement drinks can vary considerably between brands, and some may be lacking in essential nutrients.

In addition, Soylent drinks and other meal replacements are made up of the “building blocks” of food, but they lack the healthy plant compounds and other components found in whole foods, which may benefit your health ().

They May Help You Lose Weight

If you are trying to lose weight, then meal replacements may also be useful.

The time it takes to plan, shop for and prepare meals can prevent people from sticking to a diet.

Switching regular food for a calorie-restricted liquid meal once or twice a day has been shown to help people lose weight over the short term (, , , ).

However, studies so far have found mixed results over the long term, so the success of a liquid meal replacement plan probably depends on how well you can stick to it ().

It's also worth remembering this general rule: If your goal is to lose weight, you need to consume fewer calories than you burn, even in liquid form.

They May Not Be a Long-Term Solution

Although replacing regular food with meal replacement shakes could improve the quality of your diet and help you lose weight, they may not be effective over the long term ().

Maintaining weight loss and healthy eating require long-term lifestyle changes that meal replacements don't fix.

This means that if you switch back to regular eating, you may find yourself back in old patterns of behavior.

Additionally, it's important to consider that whole foods are more than the sum of their parts. They contain many different compounds that may work together to improve health.

Despite ensuring your body doesn't miss out on any essential nutrients, Soylent lacks important plant compounds, which are beneficial for your health ().

Summary: Liquid diets via meal replacements can be a convenient option that could improve the quality of your diet and help you lose weight. However, switching to a liquid diet completely may be difficult to stick to over the long term.

Safety and Side Effects

Soylent meal replacements are generally well tolerated and considered safe.

However, it's important to note that Soylent contains soy protein isolate, so these drinks are not safe for people with a soy allergy ().

In addition, a few people have reported experiencing some side effects when they started to drink Soylent, including excessive gas and some bloating.

Others have claimed that the lack of insoluble fiber in Soylent has significantly reduced the frequency of their bowel movements. However, this is all purely anecdotal, and there is currently no evidence to back up this claim.

The drinks’ phytate content is another potential issue that has been raised. Depending on the phytate content of the soy isolate used in manufacturing, the Soylent protein source may reduce iron absorption from the drink ().

However, this issue hasn't been researched, so it's unclear whether this would be a problem.

Some people have also raised concerns over the lead content of Soylent.

Lead is present in many foods because it's found in soil and plants that have absorbed it. Because of this, it’s commonly present in the food chain ().

However, it’s important to note that these concerns were specifically raised in relation to labeling laws in California. Lead levels in Soylent are below the levels deemed safe by the US Food and Drug Administration (FDA).

Summary: Soylent meal replacements are generally well tolerated and considered safe. However, they are not safe for those with a soy allergy. People have also expressed concerns over issues such as their gastrointestinal side effects and phytate content.

Should You Use Soylent Meal Replacements?

Although Soylent claims to contain all the nutrients you need, it hasn't been tested as a long-term replacement for all food.

Thus, its long-term safety is unknown.

That said, if you’re short on time and often find yourself eating junk food, using Soylent as an occasional meal replacement might help keep your diet healthy.

Overall, Soylent is a dietary tool that some people might find useful for maintaining a healthy diet.

An evidence-based nutrition article from our experts at Authority Nutrition.

CMS Id: 134109