Meal replacements have been around for decades, often marketed as powders, shakes, or bars designed to provide the nutrition of a meal in a quick and convenient form. Despite their popularity, they have developed a bad reputation. For many people, the phrase “meal replacement” conjures up images of bland, chalky shakes from the 1980s, crash diets, and unsustainable weight loss plans. But like many aspects of nutrition, the reality is a bit more nuanced. Not all meal replacements are created equal. In fact, when used in the right way they may play a helpful role in certain contexts.
What are meal replacements?
What are meal replacements?A meal replacement is typically a pre-formulated product designed to provide a balance of macronutrients (carbohydrate, protein, and fat) along with vitamins and minerals in a shake or bar. They differ from protein shakes because they aim to mimic the nutrient profile of a full meal rather than just topping up on one nutrient.
Modern formulations have come a long way and many now use higher-quality protein sources, contain added fibre, and are fortified with vitamins and minerals that meet regulatory standards. In the UK, for example, meal replacements for weight control are regulated under the European Union’s Food for Specific Groups legislation (EU No 609/2013), meaning they must meet specific nutritional criteria.
Why have meal replacements been demonised?
Despite their potential benefits, meal replacements carry a lot of baggage. Much of the negativity comes from how they were originally marketed and the way people have experienced them over the years.
Association with fad diets
In the 1980s and 90s, meal replacements were heavily marketed as quick-fix diet products, often used in crash diets that replaced every meal with a shake. People lost weight rapidly but usually regained it once they returned to normal eating patterns. Unsurprisingly, this cycle created a lasting impression that meal replacements were unsustainable and ineffective in the long term.
Perception of being ‘unnatural’
There has also been a cultural shift towards “clean eating” and whole foods. Many people view a powder or bar as “fake food,” and debates around ultra-processed foods (UPFs) have fuelled that scepticism. While some products do fall into the UPF category, it’s important to remember that processing isn’t always negative and fortification and formulation can serve a nutritional purpose.
Taste and texture legacy
Historically, many shakes and bars were overly sweet, had artificial aftertastes, or a gritty texture that made them unappealing. This reputation stuck, even though modern versions have significantly improved in taste and quality.
What are the common myths about meal replacements?
Like many nutrition topics, meal replacements have picked up their fair share of myths and misconceptions. Some of these are rooted in outdated products, others in diet culture, and some in misunderstandings about how they work.
Myth 1: Meal replacements are just for weight loss
It’s easy to see why people think this. Meal replacements first rose to prominence through weight-loss programmes and “slimming shakes” promising dramatic results. However, limiting their role to dieting overlooks the many other scenarios where they can be helpful.
Meal replacements can be a practical solution for busy professionals who might otherwise skip meals and end up grabbing something less nutritious on the go. They also have a role in nutrition as a post-exercise shake that delivers both protein and carbohydrates in the right balance when there’s little time to prepare food. For older adults, particularly those with reduced appetite or difficulty chewing, a fortified shake can be an accessible way to maintain adequate protein and micronutrient intake.
A systematic review in Obesity Reviews confirmed that partial meal replacement plans can support weight loss when combined with lifestyle changes, but they can also provide nutritional structure and convenience in other contexts [1]. The key takeaway is that they are a tool and like any tool, their usefulness depends on how they’re used.
Myth 2: Meal replacements are nutritionally inferior to real food
This myth has roots in the food-first philosophy, which is valid: whole foods contain thousands of bioactive compounds, like polyphenols and phytochemicals, that can’t be replicated in a shake or bar. It’s true that you won’t find the same diversity of plant chemicals in a powdered drink as you would in a plate of lentils, vegetables, and whole grains.
But that doesn’t mean meal replacements are nutritionally “empty.” When regulated properly, they provide all the macronutrients (protein, carbohydrates, and fat) plus fibre, vitamins, and minerals in amounts that are carefully designed to mimic the balance of a meal. For someone who might otherwise skip breakfast entirely, having a shake can mean the difference between meeting or missing their nutrient needs.
A systematic review in Nutrients showed that meal replacements, when used alongside whole foods, can support weight loss and provide adequate nutrition without adverse effects [2]. The important nuance here is that they should complement, not completely replace, whole foods. Food-first should always be the foundation, but in the real world, a shake may sometimes be the smarter choice than nothing at all.
Myth 3: Meal replacements are highly processed and therefore unhealthy
The word “processed” has become almost synonymous with “bad,” and in the age of the ultra-processed food (UPF) debate, meal replacements often get lumped into the same category as sugary snacks or fast food. While it’s true that many are technically UPFs, not all processed foods are created equal.
Monteiro and colleagues, who developed the NOVA classification, argue that the health impact of UPFs depends heavily on their formulation and the role they play in the diet [3]. For example a shake fortified with protein, fibre, and essential vitamins and minerals is very different to a fizzy drink or packet of crisps.
Modern formulations tend to use higher-quality ingredients, limit added sugars, and include fibre sources such as inulin, which can support gut health. In other words, while you wouldn’t want your entire diet to be made up of processed powders, using a well-formulated shake strategically can be a far cry from the negative stereotype.
Myth 4: Meal replacements can’t keep you full
One of the most common objections to shakes is that “liquid calories don’t fill you up.” And there is some truth to that as studies show that in general, liquids are less satiating than solid meals because they are digested more quickly.
But satiety is influenced by more than texture. Protein, fibre, and energy density are the real drivers of fullness. Modern high-protein shakes, often containing 20–30 g of protein plus fibre, are far more effective at suppressing appetite than older versions. In fact, a randomised controlled trial in the International Journal of Obesity found that high-protein meal replacements improved satiety and reduced calorie intake compared to lower-protein alternatives [4].
Myth 5: Meal replacements lead to weight regain once you stop using them
This myth comes from the yo-yo dieting history of meal replacements. People often lost weight quickly, only to put it all back on but the problem wasn’t the product itself, it was the lack of a long-term strategy.
The landmark DiRECT trial demonstrated this clearly. Participants with type 2 diabetes who followed a structured programme including meal replacements achieved remission, and those who transitioned back to whole foods with professional support maintained better outcomes over time [5]. Without support, however, weight regain was common.
This underlines the key point that meal replacements can be an effective part of a broader approach, but they’re not a permanent fix. Success depends on how they’re integrated into long-term healthy eating habits.
When Might Meal Replacements Be Useful?
- Busy lifestyles: Skipping meals can lead to overeating later in the day. A balanced shake is often better than grabbing a pastry or crisps.
- Health management: For people with obesity, diabetes, or metabolic syndrome, structured programmes using meal replacements can provide a useful intervention under professional guidance.
- Older adults: Appetite often declines with age, but nutrient needs remain high. Fortified shakes can help meet protein, calcium, and vitamin requirements when food intake is low.
- Exercise and Activity: As a recovery option, a well-formulated recovery shake can deliver protein and carbs in the right ratio, especially if you’re on the move.
What’s the bottom line?
Meal replacements are not magic bullets, nor are they inherently harmful. Like any nutrition tool, their value depends on how you use them. Demonising them overlooks their potential benefits for certain people and situations.
If you choose to use a meal replacement shake, look for options with:
- At least 15–20 g protein per serving.
- A good source of fibre (3–5 g).
- Limited added sugar (ideally <5 g).
- Fortification with essential vitamins and minerals.
Whole foods should always come first as they bring diversity, phytonutrients, and the enjoyment that a shake can’t replicate. But when life gets busy, or specific health goals are in play, a shake is often better than skipping a meal or grabbing an ultra-processed snack
References
- Astbury, N. M., Piernas, C., Hartmann-Boyce, J., Lapworth, S., Aveyard, P., & Jebb, S. A. (2019). A systematic review and meta-analysis of the effectiveness of meal replacements for weight loss. Obesity reviews : an official journal of the International Association for the Study of Obesity, 20(4), 569–587. https://doi.org/10.1111/obr.12816
- Min, J., Kim, S. Y., Shin, I. S., Park, Y. B., & Lim, Y. W. (2021). 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. Journal of the Academy of Nutrition and Dietetics, 121(8), 1551–1564.e3. https://doi.org/10.1016/j.jand.2021.05.001
- Monteiro, C. A., Cannon, G., Moubarac, J. C., Levy, R. B., Louzada, M. L. C., & Jaime, P. C. (2018). The UN Decade of Nutrition, the NOVA food classification and the trouble with ultra-processing. Public health nutrition, 21(1), 5–17. https://doi.org/10.1017/S1368980017000234
- Flechtner-Mors, M., Boehm, B. O., Wittmann, R., Thoma, U., & Ditschuneit, H. H. (2010). Enhanced weight loss with protein-enriched meal replacements in subjects with the metabolic syndrome. Diabetes/metabolism research and reviews, 26(5), 393–405. https://doi.org/10.1002/dmrr.1097
- Lean, M. E., Leslie, W. S., Barnes, A. C., Brosnahan, N., Thom. G., McCombie, L., Peters, C., Zhyzhneuskaya, S., Al-Mrabeh, A., Hollingsworth. K. G., Rodrigues.A. M., Rehackova, L., Adamson, A. J., Sniehotta, F. F., Mathers, J. C., Ross, H. M., McIlvenna, Y., Stefanetti, R., Trenell, M., Welsh, P., … Taylor, R. (2018). Primary care-led weight management for remission of type 2 diabetes (DiRECT): an open-label, cluster-randomised trial. Lancet (London, England), 391(10120), 541–551. https://doi.org/10.1016/S0140-6736(17)33102-1
