Are Meal Replacement Drinks Actually Healthy?
Are Meal Replacement Drinks Actually Healthy?
A closer look at the health claims behind liquid meals.
If you walk through any pharmacy or grocery store, you might notice that meal replacement drinks are everywhere. In fact, they are more profitable than ever, and a whole new generation of them is targeting a whole new generation of people. But are they healthy? Can they actually replace food? And beyond the marketing hype, what does the science say about them? Let's get to the bottom of the shaker bottle and try to answer every one of these questions.
Meal Replacements and Weight Loss: An Old Story with New Science
The first mass-market meal replacement was aimed squarely at American dieters as far back as 1959. Popular brands like SlimFast became household names- and remain on the market decades later- based on lofty promises of controlled calorie intake and effortless pound shedding. But do they live up to the claims?
Actually, and perhaps surprisingly, they seem to. Meal replacements have been studied more for weight loss than anything else, and many studies have confirmed that with support and under clinical supervision, they can be both safe and effective in this regard. An extensive 2021 systematic review and meta-analysis of randomized controlled trials (the highest form of evidence in existence) found that programs using meal replacements for 60 per cent of daily energy led to significantly greater weight loss after one year compared to conventional food-based diets. In 2019, an even bigger meta-analysis looking at RCTs on 7884 participants found a similar result.
Beyond Weight Loss: Inflammation and Oxidative Stress
However, health benefits aren't limited to weight loss. Several of the clinical trials looking at using meal replacements for weight loss also evaluated broader biomarkers of health, including markers of inflammation and free radical damage that underpin the pathology of most progressive illnesses.
Encouragingly, when compared to standard food-based weight loss diets, these markers tend to either stay the same or get better. One study concluded that meal replacement program participants didn't just lose weight, but also experienced improvements in inflammation and oxidative stress. These findings suggest that meal replacements, when used appropriately, aren't just safe but may even offer added protection against the risk of chronic disease.
Blood Sugar, Cardiovascular Risk, and Diabetes
The potential benefits get even more exciting when we focus on blood sugar and cardiac health. Several weight loss studies using meal replacements have tracked other biomarkers in addition to pounds lost, reporting major improvements in blood pressure, lipid profiles, and important markers of blood sugar balance and insulin sensitivity.
For individuals with type 2 diabetes, the number one risk factor for heart disease, the data is particularly compelling. One 2023 meta-analysis including 17 RCTs showed that meal replacement plans significantly reduced HbA1c, fasting glucose, and BMI. Astoundingly, the UK's massive "Soup and Shake" NHS program, which incorporated regimented calorically-controlled meal replacements, saw nearly one-third of participants with type 2 diabetes achieve total remission. Strategic use of meal replacements effectively cured their diabetes!
Better Than Hospital Food?
Historically, meal replacements have their roots in hospital care, where they retain an essential role for post-operative care and feeding those who can't eat solid food. While meal replacements have not been specifically studied as much in this context as for weight loss, quality nutrition is universally recognized as crucial for recovery. A balanced array of micro and macronutrients can reduce infection rates, speed wound healing, and shorten hospital stays.
One study showed that a calorically balanced, high-protein meal replacement formula for patients recovering from bariatric surgery helped slow muscle mass loss and prioritize fat loss. In another study, cancer patients undergoing chemoradiation maintained body weight and even reported a higher quality of life when using liquid meal replacements. It's one thing to lean on meal replacements to cut calories or because we're too busy to cook. However, for medical patients struggling to eat due to surgery or appetite loss, these formulas can be a lifeline, supplying critical calories and nutrients when it counts the most.
Fine Print and Final Thoughts
There is a time and a place for replacing food, but despite all the possible benefits, there is no perfect substitute for the real thing. And to be sure, meal replacements are not all created equal. Many such products on the market are predominantly made of ultra-processed ingredients, often containing vegetable oils, synthetic emulsifiers, and problematic artificial sweeteners.
Moreover, while meal replacements are fortified with basic (synthetic) vitamins and minerals, they generally lack the full complexity of real food, including phytochemicals, antioxidants, and diverse fibre types crucial for balancing gut health.
In the final analysis, these formulas aren't inherently good or bad; they're tools, and their value depends on precisely what's in them and how we put them to use. The science makes it clear that when used strategically and with support, they can be powerful allies to support weight loss, metabolic health, and even recovery from illness or surgery. But we also shouldn't forget that in the end, food is profoundly complex, if not impossible, to replace. Balanced meals rich in diverse plants, healthy fats, and whole proteins offer sophisticated layers of health-promoting compounds far beyond the reach of product development.
As research expands into other areas of health, such as microbiome modulation, we may discover even more potential benefits of incorporating meal replacements. In the meantime, for most of us, meal replacements should complement a real-food foundation, not replace it entirely.
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Lead photo by Aleksander Saks on Unsplash.
