Any time you're thinking of getting a bunch of nutrition into your body in the form of a liquid, you're going to encounter shakes as an option. The two biggest kinds of shakes are meal replacement shakes and protein shakes, but there's a bit more nuance to it than that, and they have some big differences.
If you're trying to decide between one or the other, it's worth knowing what you're in for.
Different Types of Shakes
While the two main categories of shakes are meal replacements and protein shakes, there are actually three main variations we want to talk about today.
1: Nutritionally Complete Meal Replacements. These are shakes that have a full array of vitamins, minerals, macronutrients, and sugars necessary to keep your body going. These are generally carefully engineered shakes like Soylent and Huel.
2: Nutritionally Incomplete Meal Replacements. These are meant to be meal replacements for caloric content, but not for nutrition. Classic meal replacement shakes like Slim-Fast fall into this category.
3: Protein Shakes. These are shakes that have even less of a varied nutritional profile because they're tools for certain kinds of purposes. They're generally made up primarily of protein powder, sometimes with additional additives like peanut butter to give it a different flavor and a few more nutrients.
We'll reference these three kinds of shakes throughout the rest of this post, so this helps you know precisely what we're talking about.
Differences in Preparation
Different kinds of shakes have different preparation requirements. In fact, even within a single brand or single kind of meal replacement, you can have different forms for the shake. Generally, they will come in two forms.
Shakes. Shakes come in shake form. Obvious, right? You can buy these off the shelves of your local grocery or health food store. You can also order them online and have cases of them shipped to your house. They're liquid, they're already balanced and formulated for specific caloric content, and they're completely ready to go. Just shake it up, twist off the cap, and drink it down.
Powders. Powder-form meal replacements and protein shakes are just that; a powder. You take a scoop or two, depending on the formula and your caloric needs, and mix it with a liquid of your choice. Usually, that will be water or milk. Shake it up and drink it. If the powder option sounds interesting to you, be sure to check out our brand of Slim Shake flavors!
The main difference, of course, is preparation time. A premade shake can be opened and consumed in a matter of seconds. A powder needs to be measured and mixed, and that takes more work than the alternative.
Now, this isn't really a difference between meal replacements and protein shakes. Protein often comes in powder form, but you can get plenty of protein-infused shakes (like Muscle Milk) at any grocery store. Conversely, meal replacements like Soylent often come in shake form, but they can also come in powder form. Both are available for both kinds of shakes.
Differences in Taste
Similar to preparation, the taste is all over the board for both meal replacements and protein shakes. The truth is, most nutrients, when pared down to their basic molecules, are near-tasteless. Protein powder on its own is a mostly neutral flavor. Meal replacements and protein shakes can both be flavored with a wide variety of additives. Usually, you can find them in vanilla, chocolate, berry, citrus, and a handful of other flavors.
Some people will note that when mixing up a shake from a powder, the texture is affected, particularly if the powder doesn't dissolve completely. That can be an issue with both kinds of shakes as well. Thus, there's not much difference in taste between different types of shakes, and both can be customized with your own additives if you want.
Differences in Nutrition
Nutrition, now we're talking! This is where the biggest differences between different types of shakes crop up.
Protein shakes are the least nutritionally complete of the bunch. Most protein shakes are just that: protein powder. They have some additional nutrients, like some sugars and some fiber, in some cases, but not always. If you're mixing one up yourself, protein powder and water is all it has at the base. Anything else is something you add to it, like a fiber supplement, sugar to sweeten it, peanut butter or fat to add some additional body, or whatever you want.
Incomplete meal replacements are the middle tier. They tend to be more nutritionally complete than protein shakes, and have correspondingly more calories. They'll have your macronutrients; the right balance of protein, fat, and carbohydrates necessary to keep your body running. What they may or may not have, however, is a mixture of vitamins and minerals you need to keep going. A lot depends on brand and formula, but meal replacement shakes are generally only meant to replace a single meal each day, and may not be meant for long-term use.
Nutritionally complete meal replacement shakes are, well, nutritionally complete. They're generally designed to have all of those vitamins and minerals, the trace nutrients, the macronutrients; everything you need to completely replace your diet and still keep on keeping on. There's still a lot of study being done to see if they actually work for the long-term, though. There are some indications that the body doesn't work right without solid food, even if the nutrients are all there in the right quantities. And, of course, there's always the social aspect of eating.
You also have to consider the caloric content of each kind of shake. Caloric content varies from shake to shake and preparation to preparation, so the numbers we're going to give you are only an estimate. Be sure to reference your own daily needs, the caloric content of the shakes you make, and everything else you eat throughout a day, to calculate your numbers properly.
Protein shakes tend to be the lowest in calories, precisely because there's so little to them. A shake that is nothing more than a scoop of protein powder and some water will be around 100 calories. That's not a lot – many people need around 2,000 calories or more for maintenance levels – but it's enough for a snack or small meal.
Augmented Protein shakes. An augmented protein shake is a shake you add something else to. One of the common recommendations is a protein shake with a banana and a scoop of peanut butter added to it. The banana adds about 100 more calories, while two tablespoons of peanut butter add another 188, leaving you with nearly 400 calories of food in your shake. That's much more viable as a meal.
Incomplete meal replacement shakes. The smaller, less complete meal replacement shakes are about double what a plain protein shake is, though it can vary from brand to brand. A Slim-Fast shake is 180 calories in a single bottle. Orgain shakes are closer to 250 calories. Muscle Milk can be as much as 320 calories.
Complete meal replacement shakes. The more nutritionally complete a shake is, generally, the more calories it will have. Soylent Complete Meal shakes are 400 calories. Huel's basic, ready-to-drink shakes are also 400 calories. Ambronite's are 425 calories. Since these are engineered products, they're generally formulated to hit the "one small meal" point of 400 calories each.
Differences in Purpose
All three different kinds of shakes are meant for different purposes.
Protein shakes are meant to be used as workout supplements, not really as meal replacements. They're aimed at fueling your body with something other than sugar and carbs, and provide your body with the protein it needs to rebuild muscle fibers. Specifically, protein shakes are generally used as a way to help your body fuel and heal after working out. They aren't usually meant to replace meals, but they may help you minimize snacking and other bad habits after working out when you're hungry.
Incomplete meal replacement shakes are meant to replace single meals or snacks throughout the day. They're usually used as a way to lose weight or to control snacking or eating urges. Many people mix up one of these for breakfast or for lunch.
Incomplete shakes are also frequently part of overall programs. Slim-Fast is the archetypal example of this. They have shakes, but they also have a variety of meals and bars that give you other nutrients in other forms. You can use shakes to replace breakfast or lunch, use bars for snacks, and still eat a normal dinner each day.
The goal with these is to help reduce your overall caloric intake while giving you something healthier than just carb-loaded or sugar-coated snacks all day. It's aimed at health and weight loss more than anything else.
Complete meal replacement shakes are, conversely, the pipe dream of tech bros everywhere. They're meant to be the space-age nutritionally complete bars and shakes, stuff you see spacers eat out of tubes in sci-fi TV shows. The overall purpose of these is to replace eating, and they're used by a few types of people:
- Tech bros and executives who are too busy to sit down for lengthy meals and just want to keep working.
- People who don't really enjoy the taste of food or the act of eating, and just want to fuel their body while they get on with life.
- Journalists who want to write posts with titles like "I Ate Nothing But Space-Nu-Meta-Meal Shakes For Two Months: Here's What Happened."
- Futurists and transhumanists want to push the envelope and progress the human species past the need for such mundane concerns as food.
If it sounds like we're being dismissing or derogatory, we're not intending to be. There's a definite role for these kinds of meal replacements in society, and they can genuinely be helpful for some people. They also may not be all they're cracked up to be, and we won't really know until more long-term studies are done on how they affect the body over time.
Long-Term Viability for Shake Consumption
One of the biggest concerns with any kind of meal replacement shake is long-term viability. We've even mentioned it a couple of times. Can you take them long-term and be fine? Well, yes and no. It depends on what you mean by long term, and what you mean by fine. It also depends on your context and lifestyle.
Protein shakes. First up, protein shakes. Can you use them long-term? Sure, if you're using them properly. Taking a protein shake before or after you work out, every day or several times a week is just fine. You're fueling your body, you're not cutting out anything you need, and you're not trying to live solely off of protein shakes.
You'll run into problems in a few cases. If you're skipping other meals in favor of protein shakes, and those meals are major meals with the nutrition you need, you could end up with a deficiency. The more prominent issue, though, is cases where you may have kidney or liver issues. The kidneys are responsible for filtering a lot out of your blood, and that includes the remnants of protein. Too much protein can cause problems if you have certain medical issues. Alone, protein shakes aren't going to hurt you. With a medical issue, they might.
Incomplete meal replacement shakes. Can you use something like Slim-Fast long-term? Sure, again, if you're doing it properly. Replacing breakfast with a shake every day is just fine. Replacing breakfast AND lunch every day? You'll probably need to make sure your dinners are always healthy and nutritionally complete. Otherwise, you won't run into problems.
Complete meal replacement shakes. Can you take something like Soylent every day? Maybe. If you use them just like you would a Slim-Fast shake and replace a meal, while still eating normal meals other times of the day, you should be fine. There were some issues with additives and excess vitamins and even contamination with early Soylent, specifically, but there are dozens of these brands out there now. Pick the one you trust.
Can you replace EVERY meal with something like Soylent or Huel? Chances are, no. Additional studies still need to be done to figure out if it's possible, and if so, how, but right now, you're likely to run into long-term issues.
So there you have it; a complete rundown of the differences between protein shakes and meal replacements. What's your favorite kind?