Do meal replacement shakes have side effects?

One of the best things I’ve found about meal replacement shakes is the convenience and flexibility they offer, especially for those of us who are always on the go. Many shakes offer the full calorie and nutrient profile that you can expect from a meal, and can be substituted into any meal plan. The best meal replacements tend to have a low calorie count but high nutritional value - meaning you can adjust and add ingredients as needed to fit your goals. This also means that you don’t have to have the same flavours and textures every day! 

Plus, they’re a healthier alternative to picking up fast food for breakfast! 

However, introducing any type of supplement into your routine carries with it questions about side effects, and meal replacement shakes are no exception. Most supplements and their active ingredients are considered to be generally safe, meaning that the majority of the population will not have an adverse reaction to using them. Meal replacement shakes are no different. This raises the question: what might the side effects be, and how can I avoid them? 



Are there side effects to using meal replacement shakes? 

The first thing to reinforce is that meal replacement shakes are not a substitute for a healthy, varied diet with lots of whole foods - you know, foods you can chew. Relying too heavily on shakes to provide all your calories and nutrients for the day can introduce certain side effects. Mostly this is down to which shake you choose to use, and how you use it. 

  1. Gut Health -  Many meal replacement shakes do not contain enough dietary fibre, which may have an impact on the health of your gut over time. A good intake of dietary fibre may help to reduce the likelihood of chronic illness, and also improve your digestion. If your shake doesn’t contain enough dietary fibre, this may have an impact on your gut health over time. (Guarner and Malagelada, 2003)
  2. Unexpected Weight Gain - Adding a meal replacement shake to your routine is often thought to help with weight loss, not gain. However, these liquid calories might not help you to feel like you’ve had a full meal, leading you to choose a more calorie dense option for your next meal. These extra calories, if not used effectively, will cause weight gain over time. (Drewnowski and Bellisle, 2007)
  3. Nutritional Deficit - Whilst high quality shakes are often fortified to contain a lot of the nutrients that your body needs, no powder can fully bridge the gap between liquid calories and a balanced, whole foods diet. Certain compounds, such as phytochemicals and antioxidants can only be found in plants, and they are vital for your continued good health, including heart health and combating inflammation in the body. (Zhang et al., 2015)
  4. Hidden Ingredients - There are often hidden dangers lurking in your supplements, especially those which are not tested by a third party. Some contain heavy metals and other contaminants from their sources and environments, which can cause low levels of heavy metal poisoning. (Tchounwou et al., 2012)
  5. Stomach Issues - The really great thing about whole foods is that they contain digestive enzymes which help your body break down what you eat into all of its nutritional parts quickly and efficiently. Meal replacement shakes do not contain digestive enzymes, and without an adequate supply, your body may struggle to digest food, leading to stomach pain, diarrhoea and bloating. (Cooper, 2000)



How do I avoid these side effects? 

An excellent question! In short, if a high quality meal replacement shake is part of a healthy and balanced diet, there’s no reason why they’d be the cause of any side effects. It is not necessarily the act of replacing a meal with a shake which can lead to these issues. 

In fact, it is largely down to the quality of the product you’re using, and the ways in which you’re using it - here are some good rules of thumb for helping you to incorporate meal replacements into your dietary routine with ease: 

  1. Avoid shakes which contain artificial ingredients, fillers and bulking agents. More often than not, it is the artificial ingredients in a product which are responsible for negative effects. Maltodextrin, for example, is a thickening agent which can cause large spikes in blood sugar. 
  2. Avoid shakes with more grams of sugar than protein - these will not keep you feeling full and sated, and may have you reaching for the cookie jar before too long, whereas higher levels of protein have been shown to keep you feeling fuller for a longer period. (Dhillon et al., 2016)
  3. Look for a shake which contains natural ingredients and is fortified with extra nutrients. Vivo Life’s WHOLE, contains 21g of plant-based protein, 25 plant-based vitamins and minerals, live cultures, turmeric, and black pepper to reduce inflammation. The best part about a nutritional shake like this? It’s only 150 calories per serving, meaning you can add it to your favourite smoothie in the mornings, giving yourself a boost of nutrition with no hassle! WHOLE is the perfect nutritious base to a good meal. 
  4. Always ensure that the company who produces your shakes has their products tested by a third party to ensure that there are no heavy metals, contaminants, herbicides or pesticides in the mix. 
  5. Read the instructions, and don’t use more per day than the manufacturer’s recommendations. Those are there to help you keep your diet balanced and healthy and prevent you from trying to live on shakes alone. It can’t be done, my friends. 

Let’s conclude by saying that if you want to avoid any potential stomach upsets, ingesting heavy metals or slowing your metabolism, then choose a high quality shake (which includes dietary fibre for gut health!) and check that it’s third party tested for heavy metals. You’ll also want to make sure that it’s incorporated into your routine in a safe and healthy way, as part of a balanced whole foods diet. 




Dhillon, J., Craig, B.A., Leidy, H.J., Amankwaah, A.F., Osei-Boadi Anguah, K., Jacobs, A., Jones, B.L., Jones, J.B., Keeler, C.L., Keller, C.E.M., McCrory, M.A., Rivera, R.L., Slebodnik, M., Mattes, R.D. and Tucker, R.M. (2016). The Effects of Increased Protein Intake on Fullness: A Meta-Analysis and Its Limitations. Journal of the Academy of Nutrition and Dietetics, 116(6), pp.968–983. doi:10.1016/j.jand.2016.01.003.

Guarner, F. and Malagelada, J.-R. (2003). Gut flora in health and disease. The Lancet, [online] 361(9356), pp.512–519. doi:10.1016/s0140-6736(03)12489-0.

Drewnowski, A. and Bellisle, F. (2007). Liquid calories, sugar, and body weight. The American Journal of Clinical Nutrition, 85(3), pp.651–661. doi:10.1093/ajcn/85.3.651.

Guo, X., Xu, Y., He, H., Cai, H., Zhang, J., Li, Y., Yan, X., Zhang, M., Zhang, N., Maddela, R.L., Nicodemus-Johnson, J. and Ma, G. (2018). Effects of a Meal Replacement on Body Composition and Metabolic Parameters among Subjects with Overweight or Obesity. Journal of Obesity, [online] 2018. doi:10.1155/2018/2837367.

Cooper, G.M. (2000). The Central Role of Enzymes as Biological Catalysts. [online] Nih.gov. Available at: https://www.ncbi.nlm.nih.gov/books/NBK9921/.

Tchounwou, P.B., Yedjou, C.G., Patlolla, A.K. and Sutton, D.J. (2012). Heavy metal toxicity and the environment. Experientia Supplementum, [online] 101(1), pp.133–164. doi:10.1007/978-3-7643-8340-4_6.

Zhang, Y.-J., Gan, R.-Y., Li, S., Zhou, Y., Li, A.-N., Xu, D.-P. and Li, H.-B. (2015). Antioxidant Phytochemicals for the Prevention and Treatment of Chronic Diseases. Molecules, 20(12), pp.21138–21156. doi:10.3390/molecules201219753.