Meal Replacements: Are They a Good Option for Losing Weight?

mrp_drinksby David Greenwalt

The weight-loss market is loaded with diet shakes and bars that promise to make you drop pounds without any effort. Advertisements for products like Slimfast make the idea of replacing your normal meals with a pre-packaged alternative look pretty tempting if you are looking to shed some extra weight, get more fit, and save some time. But do these kinds of meal replacement products (MRPs) really help you lose weight? And even if they do, are they a smart and healthy option? Learn all about MRPs as a weight loss strategy below.

Do MRPs Really Help You Lose Weight?

Several studies show MRPs to be effective weight loss tools. These studies look at people trying to lose weight, comparing those who use MRPs (like Slimfast, Optifast, and more) and those who don’t.

The results of several of these studies show that the people who use MRPs lose significantly more weight than the people who do not use the MRPs. The results have led to the widespread conclusion that weight loss interventions should include MRPs to replace one or more meals per day.

The Academy of Nutrition and Dietetics (AND) even strongly recommends MRPs (for two meals per day) as part of an effective weight-management program. Unfortunately, the results from the scientific studies, and even the AND recommendation, may not be entirely reliable.

Bottom line: Based on the findings of scientific studies, the Academy of Nutrition and Dietetics strongly recommends MRPs in weight loss interventions. Unfortunately, the validity of the studies and the recommendations is not necessarily reliable.

Are Recommendations for MRPs Biased?  

The AND strongly recommends MRP drinks, purportedly based on the strong scientific evidence from randomized controlled trials. But is this recommendation, and the evidence behind it, to be trusted?

In turns out that many of the studies mentioned have conflicting interests. Several authors of the studies are involved in some way with the companies that make these products (like Slimfast), and several of the studies were also supported by and/or funded at least in part by those same companies. These factors raise significant concerns relating to potential bias in the results of the research.

So why would AND, an organization of nutritionists and dieticians, support MRPs for weight loss if the scientific evidence is questionable? AND has a history of being sponsored by and supported by large corporations, leading to questions regarding the validity of their recommendations.

For example, Kraft, PepsiCo, Coca-Cola, and Nestlé have all been sponsors of AND, and AND has supported many of their junk-food products, even putting their seal of approval on things like Kraft Singles.

How Might Corporate Sponsorship Affect AND’s Support of MRPs?

Let’s take Optifast, for example, one of the products used in many of the studies on MRPs. It turns out that Optifast is made by Nestlé, and Nestlé also sponsored AND. Does AND potentially have a conflict of interest when it comes to supporting MRPs products like Optifast, made by a company that sponsored them? It’s possible, and some may even say probable; many people believe AND has too many conflicts of interest to be a trusted and unbiased source of information.

Bottom Line: Although the Academy of Nutrition and Dietetics strongly supports MRPs for weight loss success, their recommendations may be the result of bias and conflicts of interest.

The Pros and Cons of Using MRPs

Biases aside, MRPs aren’t always all bad. In fact, they can offer benefits to people hoping to lose weight.


  • They are convenient (easy to eat on the go, little to no prep or cleanup, don’t need to plan ahead, save you time, etc.).
  • They can help you to pack in healthy nutrients that may be lacking in your daily nutrition regimen.
  • Using MRPs takes away decision making, which can be a major pitfall when it comes to weight loss success.
  • There’s no need to calculate calories or portion sizes, as that is already done for you.


  • MRPs aren’t usually real, whole foods (and WILL lack certain nutrients found in whole foods).
  • They can be loaded with unhealthy ingredients (like preservatives, sugars, artificial ingredients, and more).
  • The sugar content in these products can be quite high.
  • Sugar alcohols are often present, which can be bad for your digestive health.
  • They are monotonous to eat, with little variation in flavor and texture.
  • MRPs products aren’t regulated like other food products, so they can be hard to get accurate information on.
  • They often lack adequate fiber for optimum health.
  • You don’t learn how to choose healthy foods and portion sizes when eating MRPs.

Bottom Line: MRPs are helpful in many ways when it comes to losing weight, but they come with many drawbacks, as well.

David Says:

I suggest eating 3-6 meals per day, depending on the person. I recommend eating real food, and if you do decide to include MRPs as part of your weight loss strategy, here are my recommendations:

  • Use an MRP once per day. Eat real food for the rest of your meals.
  • If you can, make your own MRP at home from as many real, fresh ingredients as possible. Check out the two recipes below for examples.
  • If you opt for pre-made products, avoid bars and ready-to-drink goop, which are often more processed and contain more artificial ingredients than alternatives like shake powders. Read ingredient lists and look for as pure and real of ingredients as possible.

Two of My Favorite MRP Recipes

In a blender (I use a Vitamix)

  • 1 cup of pasteurized, pure liquid egg whites
  • 1 cup of cold water
  • get this spinning on low and keep it spinning


  • 1.5 scoops of chocoberry
  • 1 tblsp of barleans lime fish oil
  • 1 tbsp of PB2 (powdered, defatted peanut butter)

Stop blender

  • Add 1/2 banana
  • handful of ice cubes
  • Put lid on blender
  • Fire it up on med/high for 30 secs


Want it with whey protein instead?

  • 2 cups of cold water
  • Get this spinning on low

Add while water spinning

  • 1.5 scoops of chocoberry
  • 1 tblsp of barleans lime fish oil
  • 1 tbsp of PB2 (powdered, defatted peanut butter)

Stop blender

  • Add 1/2 banana
  • handful of ice cubes
  • Put lid on blender
  • Fire it up on med/high for 30 secs-ish

Keep it going but turn down to medium

Why add the whey at the end? Because if you add it early it’ll all turn to frothy/bubbly crap. Add it at the end for a creamier, better mouth feel.



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  1. Carol says

    Nice article! It is so easy for people to just look at the results of the research, but not pay attention to the validity of the study and who sponsored it!! Thanks for setting this one straight!