The Benefits of Meal Replacement Shakes

Whole food purists might be tempted to view meal replacement shakes negatively because they’re processed, and not ‘real’ food. But the data suggests they can be part of a health-promoting diet.

Introduction

There was a time when I was a whole food purist. Don’t get me wrong, a mostly whole food diet is great, and I would never recommend someone eating a diet rich in whole plant foods—like what is shown on the Canadian food guide (Figure 1)—to change much of what they’re eating. But I also recognise that whole foods aren’t the be all and end all for achieving a health-promoting diet. In fact, I think we can make the case that certain processed foods are preferable than certain whole foods when it comes to promoting long-term health. For example, tofu is a processed food, but greater (compared to lower) intakes are associated with a reduction in heart disease and death from any cause (1,2), whereas greater (compared to lower) intakes of unprocessed red meat are associated with a greater risk of heart disease and type 2 diabetes (3).

Figure 1. Canada’s food guide (4).

Meal Replacement Shakes

The European Food Safety Authority defines meal replacements as distinct foods that serve as substitutes for regular foods, which are between 200 and 400 calories, between 25 and 50% protein, do not contain more than 30% of energy as fat, and contain at least 30% of the recommended daily values of vitamins and minerals (for adults) per serving (5). These foods are often used in weight loss diets, and are typically consumed as a replacement for one or more meals throughout the day. Examples of popular brands include Huel and Whole Supp.

Health Benefits

In a recent systematic review and meta-analysis of 10 studies that included individuals with at least 1 feature of poor metabolic health (over a median period of 12 weeks), using meal replacements for at least 1 meal per day was reported to significantly reduce body weight (-1.38 kg), waist circumference (-1.07 cm), a measure of blood sugar control called glycated haemoglobin (-0.74%), low-density lipoprotein (LDL) cholesterol and non-high-density lipoprotein (non-HDL) cholesterol (-1.33 mmol/L and -0.69 mmol/L, respectively), and systolic blood pressure (-2.22 mmHg) (6). These changes represent an improvement in cardiometabolic health, and are quite impressive considering that, in almost all of these studies, the group using meal replacement shakes were being compared to a group also advised and given support to eat an equally low-calorie whole food diet (6).

The Irish meal replacement brand Whole Supp formulate their meal replacement shakes with a number of whole food ingredients such as those presented here.

These results are in agreement with other systematic reviews and meta-analyses which included different population groups (e.g., those living with type 2 diabetes) (7,8,9,10). Meal replacement shakes help with weight loss by helping people to stick with a low-calorie diet. This is likely because these shakes are an easy, ready-to-eat option, which simplifies dietary choices and reduces the likelihood of choosing options less likely to facilitate weight loss (5). In addition, their high-protein, low-fat composition may promote feelings of fullness (5). Their ability to reduce body weight largely explains their associated health benefits (e.g., reductions in blood sugar, blood pressure, etc.). In addition, their low-saturated fat composition, paired with their often relatively high-fibre content, helps to explain their ability to substantially lower LDL cholesterol and non-HDL cholesterol. This is a major benefit of their use, as LDL cholesterol and non-HDL cholesterol are causal risk factors for heart disease (11).

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PS. Check out our ‘Technical Terms’ section at the end of this article for an explanation of some key scientific terms used throughout this article (i.e., those highlighted in bold orange text).

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Meal Replacement Shakes for Athletes

While the literature discussed so far has looked at how meal replacement shakes can help people lose weight, I actually think there are a number of potential use cases beyond this goal. For example, I think you could make the case that meal replacement shakes are a convenient way for athletes to ensure they’re getting enough calories, protein, and carbohydrates throughout the day. Because it is so important that athletes fuel regularly, packing a meal replacement shake for school or work could be an easy way to help athletes to meet their fuelling needs. This is especially true for those with busy schedules.

Summary

Despite being 'processed', meal replacement shakes have been consistently shown to improve measures of cardiometabolic health, and they provide an easy and convenient means to fuel. In addition, the semi-whole food, plant-based composition of leading brands have the added benefit of delivering good amounts of fibre and polyphenols that positively influence health, while having a low environmental impact. Of course, these foods are not necessary for good health, but if you are looking for a convenient way to eat better and improve your health, they’re a good option.

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As always, thanks so much for reading and have a lovely weekend!

Patrick Elliott, BSc, MPH

Health and Nutrition Science Communication Officer at Training121

Instagram: @just.health.info

Twitter/X: @PatrickElliott0

References

(1) Yan Z, Zhang X, Li C, Jiao S, Dong W. Association between consumption of soy and risk of cardiovascular disease: A meta-analysis of observational studies. Eur J Prev Cardiol. 2017;24(7):735–47. Available at: https://academic.oup.com/eurjpc/article/24/7/735/5926697

(2) Chen Z, Qian F, Hu Y, et al. Dietary phytoestrogens and total and cause-specific mortality: results from 2 prospective cohort studies. Am J Clin Nutr. 2023;117(1):130–40. Available at: https://www.sciencedirect.com/science/article/pii/S0002916522105332

(3) Shi W, Huang X, Schooling CM, Zhao JV. Red meat consumption, cardiovascular diseases, and diabetes: a systematic review and meta-analysis. Eur Heart J. 2023;44(28):2626–35. Available at: https://academic.oup.com/eurheartj/article/44/28/2626/7188739

(4) Canada’s food guide. 2024. Available at: https://food-guide.canada.ca/en/

(5) EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA). Statement on the conditions of use for health claims related to meal replacements for weight control. EFSA Journal. 2015. Available at: https://efsa.onlinelibrary.wiley.com/doi/abs/10.2903/j.efsa.2015.4287

(6) Noronha JC, Nishi SK, Khan TA, Blanco Mejia S, Kendall CWC, Kahleová H, Rahelić D, Salas-Salvadó J, Leiter LA, Lean MEJ, Sievenpiper JL. Weight management using meal replacements and cardiometabolic risk reduction in individuals with pre-diabetes and features of metabolic syndrome: A systematic review and meta-analysis of randomized controlled trials. Obes Rev. 2024;25(7):e13751. Available at: https://onlinelibrary.wiley.com/doi/10.1111/obr.13751

(7) Astbury NM, Piernas C, Hartmann-Boyce J, Lapworth S, Aveyard P, Jebb SA. A systematic review and meta-analysis of the effectiveness of meal replacements for weight loss. Obes Rev. 2019;20(4):569–87. Available at: https://onlinelibrary.wiley.com/doi/10.1111/obr.12816

(8) Noronha JC, Nishi SK, Braunstein CR, Khan TA, Blanco Mejia S, Kendall CWC, Kahleová H, Rahelić D, Salas-Salvadó J, Leiter LA, Sievenpiper JL. The Effect of Liquid Meal Replacements on Cardiometabolic Risk Factors in Overweight/Obese Individuals With Type 2 Diabetes: A Systematic Review and Meta-analysis of Randomized Controlled Trials. Diabetes Care. 2019;42(5):767–76. Available at: https://diabetesjournals.org/care/article/42/5/767/40494/

(9) Min J, Kim SY, Shin IS, Park YB, Lim YW. The Effect of Meal Replacement on Weight Loss According to Calorie-Restriction Type and Proportion of Energy Intake: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. J Acad Nutr Diet. 2021;121(8):1551–64.e3. Available at: https://www.sciencedirect.com/science/article/pii/S2212267221003026

(10) Zhang Y, Chen X, Allison DB, Xun P. Efficacy and safety of a specific commercial high-protein meal-replacement product line in weight management: meta-analysis of randomized controlled trials. Crit Rev Food Sci Nutr. 2022;62(3):798–809. Available at: https://www.tandfonline.com/doi/full/10.1080/10408398.2020.1829539

(11) Ference BA, Ginsberg HN, Graham I, Ray KK, Packard CJ, Bruckert E, Hegele RA, Krauss RM, Raal FJ, Schunkert H, Watts GF, Borén J, Fazio S, Horton JD, Masana L, Nicholls SJ, Nordestgaard BG, van de Sluis B, Taskinen MR, Tokgözoglu L, Landmesser U, Laufs U, Wiklund O, Stock JK, Chapman MJ, Catapano AL. Low-density lipoproteins cause atherosclerotic cardiovascular disease. 1. Evidence from genetic, epidemiologic, and clinical studies. A consensus statement from the European Atherosclerosis Society Consensus Panel. Eur Heart J. 2017;38(32):2459–72. Available at: https://academic.oup.com/eurheartj/article/38/32/2459/3745109

Technical Terms

Systematic review: A systematic review is a comprehensive summary of all the relevant research on a specific topic. It includes multiple studies to provide a clear picture of what the science says about that topic. Studies are included such that they meet certain eligibility criteria, which are defined by the researchers. For example, the researchers may only want to look at a certain age group of people, or a certain study type. This helps to narrow the focus of the review to a particular research question.

Meta-analysis: A meta-analysis is like a big study of studies. Instead of just looking at one study, it combines the results of multiple studies on the same topic to see if there are any overall patterns or trends. By doing this, researchers can make more reliable conclusions about the topic they're studying—but only if the meta-analysis is well done.

Median: The median value of something is the value bang smack in the middle of all other values, which divides the numbers so that an equal amount are below, and an equal amount are above. In other words, it is the middle value of a range of values.

Statistical significance: This is a term to describe the likelihood of whether a finding in a study is a ‘real’ finding, or if it is the result of chance. Statistical significance is denoted by a p-value, which is usually set at a significance (alpha) level of 0.05. This means that if a result is significant at this level (p≤0.05), we can say that the probability of getting a value as or more extreme than the observed value (under the assumption that the null hypothesis is true) is less than 5%. In other words, it is more likely that this finding is not the result of chance than if the p-value was >0.05 (although this is not always the case).

Polyphenols: These are a group of phytochemicals—or plant nutrients—that act as antioxidants and improve our health. Health benefits from polyphenol intake include reductions in LDL cholesterol, improved cognition, and other metabolic improvements.