The Difference Between Meal Replacements and Protein Shakes

By Rachael Attard, Updated Jul 14, 2021

Meal replacements and protein shakes can help you achieve your fitness goals and assist you with weight loss. But each one serves a different purpose and will help you in different ways.

In this post, I’ll explain what each one does and how to pick the right one for you. :)

What Are Meal Replacements?

Meal replacements were first created to help athletes who needed a quick, but effective, source of fuel for their workouts. Today, people from various lifestyles use meal replacements.

Meal replacements are drinks or bars that are meant to substitute a meal. They contain the nutrients and calories that you would get from a meal. People who are busy, don’t like to cook, or have certain dietary goals can sometimes use them in place of a traditional sit-down meal.

Why Do People Drink Meal Replacements?

Some people are turned off by the idea of non-traditional meals. However, others find that meal replacements can help in achieving their fitness and diet goals. :) Here’s why:

They’re Convenient When You Don’t Have Time to Meal Prep

I understand that life gets busy! Parenting, working, attending school, and managing relationships take time. Because of this, you might not always have the time to meal prep or cook a healthy meal. Some people find it hard to cook or prepare meals for themselves when they are stressed out or struggling with their mental health.

Instead of grabbing fast food or eating out, some people pick up meal replacements. They can be a healthier option when you need something quick and filling.

They Provide Nutrients That You Need

High-quality meal replacements are designed to give you the nutrients that you need. The best ones will contain fiber, protein, and vitamins, and minerals.

If you’re trying to cut back on calories, it can be tricky to still get enough nutrients in. Some people have trouble with eating the correct amount of nutrients no matter what. Meal replacements could make this process a lot easier for you.

They Might Help With Weight Loss

To lose weight, you need to burn more calories than you consume. For most people, this requires keeping track of their diet and making sure they’re not eating too much. But tracking calories and eating correct portion sizes can be difficult! Not only can it be complicated, but it can also leave some people feeling hungry.

Meal replacements can help people feel full without eating too many calories. One study showed that people who followed a partial meal replacement diet plan lost 5.6 more pounds (2.4 kg) in three months than those who did not.

Some people also find that meal replacements help them maintain their healthy weight after they’ve lost weight too.

Some Meal Replacements Are High in Protein

Many meal replacements are high in protein. This is good news for people who are interested in building muscle and who struggle to eat enough protein from traditional meals.

Eating enough protein also helps with weight loss. Meals that include protein tend to make people feel more satisfied, which helps them eat fewer calories overall. Protein also helps to reduce cravings, including late at night.

People who eat diets that are high in protein also tend to have:

Less body fat
An easier time maintaining their weight
More lean muscle mass

How to Choose Your Meal Replacement

There’s no standard meal replacement. Some are made better than others. If you want to try a meal replacement, you should consider:

The nutrients in the meal (does it contain what you need)
The sugar content
If the meal replacement has been tested by a third-party
If you can afford it (consider the price per meal)

Meal replacements should also contain one-third of the daily vitamins and minerals. Try to pick ones that contain the following:

220-230 calories per serving
Less than 5 grams of fat per serving
3-5 grams of fiber per serving
At least 10 grams of protein, but ideally more than 15 grams

If you’re concerned about your fiber intake, you can always eat a meal replacement with some vegetables or a piece of fruit to increase your fiber.

I recommend that you avoid meal replacements that contain corn syrup and hydrogenated vegetable oils.

WHAT ARE PROTEIN SHAKES?

Protein shakes are considered dietary supplements. They aren’t meant to replace meals. Instead, dietary supplements enhance your diet.

Protein shakes add additional protein to your diet, but they typically also include some carbohydrates and fat. They can come in powder form that you mix with a liquid (typically water), or you can buy them as packaged drinks.

Why Do People Drink Protein Shakes?

Protein shakes can be useful to people for a variety of reasons. People drink them in order to:

Help With Muscle Gain

Eating enough protein is an essential part of gaining muscle, and protein shakes can help athletes and people who are into fitness get enough protein in their diet.

People who combine protein shakes with resistance training will typically see muscle growth. They will also experience faster recovery times after strength workouts, and they should notice that their physical performance improves.

Some people want to lose weight without losing muscle mass. This can be challenging to do without eating enough protein. However, studies show that people who lose weight while still eating plenty of protein lose less muscle mass than people who eat less protein. Because of this, people who are on a weight loss diet often drink protein shakes to help them consume plenty of protein without eating too many calories.

Helps You Stay Fuller for Longer

Protein helps keep you full and it does this in two different ways:

Protein slows down your digestive system, helping you feel fuller for longer.
Protein affects the hormones that control how full you feel, meaning that you will be less likely to want to overeat.

Research suggests that all types of protein, including protein from protein shakes, have these hunger-reducing effects. In fact, one study found that shakes with 20-80 grams of protein all decreased hunger by 50-65%.

Boost the Metabolism

Diets that are high in protein boost your metabolism. They help you burn more calories in general, even when you are asleep!

Part of this has to do with the fact that protein helps you build muscle, and muscle burns more calories than fat.

In addition to this, your body uses more calories to digest protein than it does to digest fat or carbohydrates. This is called diet-induced thermogenesis (DIT).

High protein diets also stimulate a process called gluconeogenesis. In this process, your body produces glucose from proteins or fats instead of carbs. Your body burns extra calories during this process.

Lose Weight and Abdominal Fat

High-protein diets can help people lose weight from the belly area. Losing fat from this region is especially good for you. Abdominal fat is linked to chronic inflammation, which can cause insulin resistance and heart disease.

One study showed that women who consumed an extra 40 grams of protein per day lost slightly more fat around their midsection than women who did not eat the extra protein.

How to Choose Your Protein Powder/Shake

There are a lot of different types of protein powder and available. I love that there are a lot of options, but that can make it hard to choose too. :)

Different Types of Protein Powders

Different protein supplement shakes use different powders. These powders are typically sourced from at least one of the following.

Whey: A protein found in milk. Whey contains essential amino acids, and it is quickly absorbed.
Casein: The other protein found in milk. Casein contains essential amino acids, and it is slowly absorbed.
Hemp: This is high in omega-3 and omega-6 fats, but it is low in the essential amino acid lysine. It is plant-based.
Pea: This protein is low in the non-essential amino acids cystine and methionine. It is plant-based.
Soy: This protein is plant-based, and it contains all essential amino acids.
Rice: This protein is low in the essential amino acid lysine. It is plant-based.

Plant-based protein powders and shakes often combine multiple types of plant-based powders in order to balance out the missing amino acids.

You can buy shakes pre-made, or you can mix the powder with water on your own.

What I Recommend

I use and love whey protein, and it is what I recommend to most people (unless you can’t eat products derived from dairy). I like whey because:

Your body absorbs it quickly, helping you feel less hungry faster.
Studies show that people lose more fat when they use whey protein, rather than soy protein.
Research suggests that whey helps people maintain their muscle mass when they are losing weight.
It contains all essential amino acids.

Even though I have a favourite, all the different protein powders I mentioned can help give you the protein that you need. If you can, most experts suggest that you chose a protein powder that contains all essential amino acids. Whey, casein, and soy all do this.

However, it isn’t a huge problem to consume the other powders that are lacking some essential amino acids. If you do, just be sure that you are getting protein from other sources too. That will help make up for the deficiency.

The Main Differences Between Meal Replacements and Protein Shakes

The big difference between meal replacements and protein shakes is their purpose. Meal replacements are substitutes for a meal, but protein shakes are only meant to provide you with extra protein. Because of this, meal replacements contain all the nutrients that you need, but protein shakes contain just protein (with small amounts of carbs and fat).

If you struggle to get enough protein in your diet through regular meals, consider trying protein shakes.
If you don’t have time to make meals or want a meal that provides all your nutrients for you, consider trying meal replacement shakes. Meal replacements contain protein and other nutrients.

In addition to this, protein shakes are always liquid, but meal replacements can be drinks or bars.

Both meal replacements and protein shakes can be quick, effective ways to support your weight loss and/or fitness goals. If you choose to use meal replacements or protein shakes to support your needs, that’s great! Just pick the right one for you. :)

Love Rachael Xx

Article written by Rachael Attard

Rachael is an Australian born certified personal trainer and nutritionist who holds a Bachelor degree in Science.

After struggling for years to find an exercise and diet program that is tailored to women striving for lean and toned body with no bulk she designed her Lean Legs Program. This program is tailored to each body type and focused on helping women get toned but feminine bodies, without getting bulky.

Her mission is to empower women and help them stay in shape in a healthy and balanced way.