Some links on our site may earn us a commission at no extra cost to you. Learn more.
Weight management is a medical topic. Meal replacement shakes are not right for everyone, and sustained calorie restriction should be discussed with your doctor or a registered dietitian — especially if you take medications, are pregnant, or have a history of disordered eating.
Among the big three meal replacement shakes, Huel Black Edition is the standout for anyone whose goal is losing fat while keeping muscle: it packs double the protein of Soylent at the same 400 calories. Soylent Original remains the smoothest all-purpose meal-in-a-glass, and SlimFast is the only one actually engineered around a weight-loss program — with the smallest servings and the smallest price tag. Which one fits depends on where you want your calories to come from, so let’s follow the numbers.
Three products, three philosophies
These shakes look interchangeable on a shelf and couldn’t be more different in intent. Huel Black Edition is a 400-calorie complete meal that happens to be high-protein: 40 g of plant protein, 27 vitamins and minerals, and up to 11 g of fiber per serving, at $2.65 a meal on Huel’s own pricing ($45 for a 17-meal bag, July 2026). It’s the one built like food you plan a day around.
Soylent Original powder is the convenience veteran: the same 400 calories per two-scoop serving but a leaner 20 g of protein and a notable 15 g of sugar, at roughly $2.80 per serving per BarBend’s 2026 review of the tub pricing. Owners consistently rank its texture the least gritty of the powders — the shake you’ll actually finish is worth something.
SlimFast’s Advanced Nutrition high-protein smoothie mix is the only one sold explicitly as a weight-loss tool. A scoop is just 100 calories with 12 g of protein and 1 g of sugar; prepared with 8 ounces of fat-free milk as directed it lands at 190 calories and 20 g of protein, per the retailer nutrition listing. At $14.38 for a 12-serving canister, the sticker price is a fraction of the other two — but note it’s replacing a smaller meal.
Protein per 100 calories: the number that matters when cutting
When you’re eating less, every calorie has to carry more protein — that’s what helps preserve muscle on a deficit. So we computed protein density and cost on a common footing, using each maker’s published nutrition and current prices. The last column normalizes cost to a 400-calorie eating occasion, which is what makes a $14 canister and a $45 bag comparable.
| Per serving | Protein | Sugar | Protein per 100 kcal (our math) | Cost per 400 kcal (our math) | |
|---|---|---|---|---|---|
| Huel Black Edition | 400 kcal | 40 g | low (no artificial sweeteners) | 10.0 g | ~$2.65 |
| Soylent Original | 400 kcal | 20 g | 15 g | 5.0 g | ~$2.80 |
| SlimFast high-protein mix (with fat-free milk) | 190 kcal | 20 g | 13 g (mostly milk’s lactose) | ~10.5 g | ~$2.40 + two cups of milk |
The table splits the field cleanly. Huel and prepared SlimFast are twice as protein-dense as Soylent — and Soylent’s 15 g of added-sugar-heavy sweetness per serving is the spec that sits worst with a weight-management goal. SlimFast’s density comes with an asterisk: half its prepared protein arrives via the milk you supply, and a 190-calorie shake is a snack-sized meal that works as designed only inside its shake-plus-sensible-meals program.
Where each one breaks down
- Huel Black: the 40 g of pea-and-rice protein makes it the thickest and most filling — some owners find it heavy as a daily breakfast, and the $45-per-bag outlay stings upfront even though per-meal cost is the lowest of the three complete meals.
- Soylent: lowest protein density here and the most sugar; fine as an occasional skipped-lunch rescue, harder to justify as the backbone of a cut.
- SlimFast: smallest serving means it lives or dies by what you eat around it, and its sweetener-forward flavor profile divides owners more than the other two.
How we compared
Nutrition and pricing come from Huel’s product page, BarBend’s 2026 Soylent powder review, and retailer nutrition listings for SlimFast (all July 2026); the protein-density and cost-normalization math is our own. We don’t taste-test, we make no claims about what any product will do for your weight, and our editorial standards explain how we handle health-adjacent comparisons.
Still deciding
Are meal replacement shakes good for weight loss?
They’re a portion-control tool, not a solution: a shake makes one meal’s calories predictable, which some people find easier to sustain than restricting a cooked meal. Whether that suits your health situation is a conversation for your doctor or dietitian.
Which shake has the most protein per calorie?
Huel Black Edition among ready-mix complete meals — 40 g in 400 calories, or 10 g per 100 kcal. SlimFast prepared with fat-free milk matches that density, but only because the milk contributes half the protein.
Can I replace every meal with shakes?
That’s not something to attempt without medical supervision. These products are designed to replace some meals; full liquid diets belong under professional care.
Why is SlimFast so much cheaper per canister?
Smaller servings and outsourced calories: each 100-calorie scoop assumes you’ll add milk, so part of the real cost and nutrition arrives from your fridge. Normalized to the same 400 calories, the three land within about forty cents of each other.
Working on the same goal from other angles? Our protein shakes vs. powders comparison covers preserving muscle on a smaller appetite, the portion control tools face-off handles the solid-food side, and our tracking comparison sorts out how to measure progress. More in Weight Management.
