Meal replacement powders can be great for weight loss, building lean muscle, and portion control. But with so many on the market, which will actually help you slim down and deliver the nutrition you need?

That’s why we turned to the mecca of supplements (and everything else)—Amazon—to review the most popular meal replacement powders: RSP’s Truefit, SlimFast’s High Protein Meal Replacement, Flavcity’s Protein Smoothie, Garden of Life’s Meal Replacement, and Ka’Chava’s All-In-One Nutrition Shake.

With the help of dietitian and nutritionist, Jordana Tobelem (RD/LDN), we tried and tested each product. We considered macros, ingredients + nutrition, taste, and satiety + tolerability—and in the end, one clear winner emerged. Keep reading to find out which!

Should I Take a Meal Replacement?

Research shows that meal replacements can help reduce calorie intake. In fact, a 2022 meta-analysis in the Journal of Obesity concluded that meal replacements can support weight loss, especially when paired with exercise and healthy lifestyle habits.¹ Another study showed that using meal replacements led to more weight loss than using food alone.²

Still, don’t rely too much on these tools. According to our Registered Dietitian, Jordana, “Meal replacements should complement, not replace, healthy eating habits. Regular exercise, a varied diet rich in fruits and vegetables, and mindful portion control—remains key for lasting results.”

What Should I Look for in a Meal Replacement?

When choosing a meal replacement, here’s what our Registered Dietitian, Jordana, says to look for:

• High-quality protein builds muscle and promotes metabolic function (AKA calorie burning). Whey protein is considered the gold standard for muscle growth, as it’s a complete protein (includes all BCAAs) and is absorbed the quickest.
• Low sugar prevents insulin spikes and lowers risk for chronic disease.
• Healthy fats like MCT oil promote satiety and assists in absorbing key vitamins and minerals.
• Digestible formulations with ingredients like grass-fed whey, pre- and probiotics reduce bloating and support gut health.
• Real food nutrients from fruits and vegetables ensure a broad range of vitamins, minerals, and antioxidants that mimic a balanced meal.
• Taste matters just as much as nutrition: if the flavor or texture doesn’t appeal to you, it’s unlikely you’ll stick to it consistently.

How do our contenders compare on macronutrients, ingredients, taste, tolerability, and price? Let’s find out!

Macronutrients: TrueFit Leads With High Protein per Calorie, Healthy Fats, and Fiber

A good way to evaluate meal replacements is by protein per calorie—the higher the ratio, the more lean-building power. TrueFit comes out on top with 0.16g of protein per calorie. Half of TrueFit’s carbs come from fiber, which helps support satiety and steady energy. Finally, TrueFit’s 3g of fat are derived from MCT oil, a healthy fat that reduces appetite and boosts energy.³

FlavCity provides the same protein per calorie, but almost zero fiber and double the sugar. Ka’Chava’s protein per calorie is the worst in this test at just 0.10g of protein per calorie; and it also has the highest sugar (7g). Garden of Life and SlimFast also have the lowest protein, at 20g and 12g, respectively.

Overall, TrueFit hits the best ratios of high-quality protein, healthy fats, and prebiotic fiber.

Ingredients & Nutrition: TrueFit Wins With Grass-Fed Whey, Veggies & Probiotics

TrueFit again takes the top spot for ingredients & nutrition. Its primary ingredient is grass-fed whey (a better whey option for those with lactose sensitivity). It’s the only product in this test that includes prebiotics (to nourish beneficial gut bacteria) and probiotics (bacillus coagulans, proven to support digestion and immune function, and prevent bloating). Broccoli, spinach, strawberry, and raspberry powders deliver essential vitamins like Vitamins A, C, and K, as well as minerals like iron and magnesium. Finally, it has no artificial preservatives or sweeteners.

FlavCity’s Protein Smoothie combines grass-fed whey with collagen, which may help support joint, skin, and nail health.⁴ But, with no vegetable or superfood ingredients, it doesn’t quite measure up to TrueFit’s more comprehensive vitamin, mineral and antioxidant profile. If collagen is something you’re interested in trying, we recommend using a separate supplement (it’s also a lot cheaper!).

Both Ka’Chava and Garden of Life rely on plant-based protein blends, making them viable options for vegans or those with severe dairy sensitivities. However, plant protein can have an incomplete amino acid profile, which is less effective for building and maintaining muscle. Moreover, Ka’Chava contains 7 grams of sugar—which is simply too high per serving.

Finally, SlimFast uses soy protein isolate—a lower quality protein linked in some research to potential hormonal disruption⁵—and is loaded with artificial sweeteners, flavors, and other ingredients.

Taste: It’s a Tie between Ka’Chava & TrueFit

For consistency, our testers tried the vanilla flavors of each product. Ka’Chava and TrueFit were generally enjoyed by our testers. Testers like TrueFit’s “lighter vanilla” flavor, creamy texture, and noted it tasted like a “not-too sweet milkshake”. Ka’Chava’s “earthiness” wasn’t a surprise given its plant based protein; it tasted more “health foody” but still quite good.

FlavCity turned off some testers with its very sweet, “cake batter-y” taste and texture. Garden of Life was deemed “OK” but chalky, likely due to its use of plant protein. Finally, reviewers noted SlimFast’s artificial taste and cloying sweetness, putting it in last place.

Satiety & Tolerability: TrueFit Wins with High Satiety, and Gut Support

We asked testers to note their satiety (how full they felt) and if they experienced any digestive discomfort with each product. Here’s how each “shaked out.”

TrueFit

Testers reported feeling satisfied without bloating—likely thanks to grass-fed whey, prebiotic fiber, and probiotic cultures that work together to aid digestion. Several participants mentioned looking forward to starting their day with TrueFit. “I actually enjoy having it first thing in the morning. The probiotics and prebiotics seem to improve regularity and reduce bloating and gas,” said one reviewer.

FlavCity

‍Thanks to grass-fed whey, FlavCity provided expected satiety for most testers—though a few felt it wasn’t as filling as TrueFit, potentially due to low fiber. No major digestive complaints emerged, but the “sweet cake batter” taste and texture was “tough to take every morning” for one reviewer.

Ka’Chava and Garden of Life‍

Both Ka’Chava and Garden of Life use plant-based proteins and a few testers mentioned mild bloating and gassiness with each. “I appreciated the vegan formula, but I felt bloated afterward,” said one Ka’Chava user.

SlimFast

Slimfast’s smaller serving sizes and lower protein led to some testers needing to double up on scoops. One participant explained, “It’s so sweet that I can’t imagine drinking it every day without getting sick of the taste.”

Taken together, TrueFit emerged as the top pick for ongoing daily use, offering good taste, satiety and no digestion-related issues.

Price: SlimFast Wins as the Cheapest Per Gram Option

When comparing cost per serving and cost per gram, SlimFast emerged as the least expensive at $0.04 per gram—unsurprising given its reliance on lower-quality ingredients, like soy protein isolate and artificial sweeteners.

If you’re able to spend a bit more, TrueFit is the clear value winner. With premium grass-fed whey, pre/probiotics, and real-food nutrients, it’s about tied for the second most affordable option.

FlavCity and Ka’Chava were the most expensive in this test.

The Overall Winner: TrueFit

After evaluating the macros, ingredients, taste, digestibility, and price of these leading meal replacements—we found one clear winner: RSP’s TrueFit.

For TCD testers, TrueFit’s balance of grass-fed whey, prebiotic fiber, probiotics, and minimal sugars made it the top option for daily use.

“I recommend TrueFit because it uses clean ingredients, and tastes great without loading up on fillers or artificial sweeteners,” says our dietitian Jordana Tobelem, RD/LDN. “It’s close to an optimal combo of quality protein, healthy fats, and gut support.”

Ready to try TrueFit? With TCD, save 15% on your first order.

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^{1. International Journal of Obesity: Meal Replacements Can Support Weight Loss}

^{2. Journal of the Academy of Nutrition and Dietetics: Meal Replacement is More Effective for Weight Loss Than Food Alone‍}

^{3. Cleveland Clinic: MCT Oil Health Benefits}

^{4. Cleveland Clinic: Collagen Benefits}

^{5. NIH: Hormonal Effects of Soy}

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