Meal replacement shakes versus protein shakes – what is the difference?

By Kamyra La Fauci – Accredited Practising Dietitian

When visiting your local pharmacy, supermarket or even health food store, you’ll likely notice the abundance of meal replacements and protein shakes on offer. But what actually are meal replacements, and how are they different from protein shakes? Do they have the same uses, and are they suitable for everyone? Our Accredited Practising Dietitian Kamyra answers all your questions below! 

What is a meal replacement shake and how should it be used? 

A meal replacement shake is a portion controlled, nutritionally balanced product that is typically formulated using skim milk powder, and is supplemented with fibre, fats, protein and several vitamins and minerals. Depending on the brand, meal replacements can also be offered as soups, bars and sometimes even desserts. 

Meal replacements have various uses, but typically they are designed to replace a meal or several meals across the day to lower total calorie intake and assist with weight loss. Also, meal replacements are frequently used by those who are undergoing a weight loss procedure, for example an Intragastric Balloon (IGB), Endoscopic Sleeve Gastroplasty (ESG) or a Sleeve Gastrectomy (SG). In these instances, meal replacements are used beforehand as part of a specialised Very Low Calorie Diet (VLCD) designed to shrink the liver and reduce anaesthetic risk, and after the procedure to support nutrition needs during the various diet progression phases.  

There are so many benefits of using meal replacements to assist with weight loss: 

• Affordability – meal replacements usually sell for approximately $4 per shake. To find a meal for $4 is almost unheard of!
• Convenience – meal replacements are very easy to transport. They often come in sachets and be kept in a handbag or even in your desk draw at work. 
• Nutritious – you are guaranteed a nutritionally balanced meal (depending on the brand).
• Quick and easy – perfect for people who lead busy lifestyles and struggle to find time to make healthy meals. 
• Portion controlled – using meal replacements makes it easier to track your daily intake of calories which is helpful for reaching your weight loss goals.

There are various meal replacements on the market, but it’s important to know they are not all created equal. When purchasing meal replacements, be sure to choose a brand that is classified as a Formulated Meal Replacement. Formulated meal replacements must adhere to strict guidelines which are governed by FSANZ (Food Standards Australia and New Zealand) and must contain at least 12g protein, 850kJ and 25% of the recommended daily intake (RDI) of 16 vitamins and minerals. A product that ticks these boxes will usually be marketed a “Formulated Meal Replacement”, so look for this claim on the product packaging. Our most loved meal replacement product brands are Impromy, Flexi and Optifast. 

What is a protein shake and how does this differ from a meal replacement shake? 

There are several differences between protein shakes and meal replacements, particularly when comparing their intended use and nutrition profiles.  

Protein shakes are typically used to help people increase their consumption of protein in their diet. It’s a product that is used to supplement a diet, versus replacing a meal and therefore is not designed for weight loss. They are commonly used by gym go-ers who are wanting to increase their muscle mass, or for athletes who may have increased requirements for protein in their diet and can be consumed during and after workouts. 

When looking at the nutrition profile of a protein shake, these products are typically formulated using either whey, soy or casein protein isolate and also contain flavours (both natural and artificial) and either sugar or sweeteners for taste. On average a protein shake contains 25-30g protein and is approximately 120-150 calories. 

Can protein shakes be used to replace a meal versus a meal replacement? 

In short answer, no. As protein shakes are not designed to replace a meal, they lack key nutrients that should be featured in a meal including fibre, fats, low GI carbohydrates or vitamins and minerals. Over time this could lead to nutrient deficiencies if protein shakes were used to replace meals. Also, as a protein shake is only 120-150 calories, the calories are insufficient to keep you feeling fuller and will likely result in increased snacking which may interfere with your weight loss goals.  

So in summary, there are several differences between meal replacement shakes and protein shakes and it’s important to understand these key differences before incorporating these products in your diet. Please note, it is always best to discuss the use of meal replacements or protein supplements with your dietitian or doctor prior to use to determine if they are suitable for you.