Optimum Nutrition
Marshmallow Crunch
TL:DR
In 2 Sentences
A rice‑crispy‑style build—soy‑protein crispies under a low‑sugar white‑chocolate‑style coating—using a soy‑plus‑whey blend to reach 20g of protein at 217 calories.
When to choose Optimum Nutrition Marshmallow Crunch
Reach for it when you want a marshmallow cereal‑treat vibe with real protein after a workout or during the 3 p. m.
slump. Skip it if you avoid wheat or soy, or if sugar alcohols and refined fibers tend to bother your stomach.
What's in the Optimum Nutrition bar?
Optimum Nutrition’s Marshmallow Crunch is built like a modern protein treat: crunchy soy‑protein crispies set in a sugar‑free white‑chocolate‑style coating, then held together with soluble fibers.
The protein backbone is a blend—soy protein isolate leads (it’s the main component of the crispies) with support from dairy proteins (whey isolate/concentrate and milk protein concentrate)—delivering 20g, which lands around the 90th percentile for bars.
Carbs skew toward refined, low‑glycemic binders (fructo‑oligosaccharides, polydextrose, and isomalto‑oligosaccharides) rather than grain flours; fat stays modest and comes mainly from palm and palm‑kernel oils in the coating; and sweetness is mostly from a sugar alcohol (isomalt) plus a tiny dose of sucralose.
That’s how you get a marshmallow‑and‑crunch experience—courtesy of the white‑chocolate flavor coating and milk flavorings—without a big sugar spike.
- Protein
- 20 g
- Fat
- 6 g
- Carbohydrates
- 17 g
- Sugar
- 4 g
- Calories
- 217
Protein
2015HIGHTwenty grams of protein come from a mixed stack: soy protein isolate in the crunchy crispies does much of the lifting, with dairy proteins (whey isolate/concentrate and milk protein concentrate) rounding out the amino acid profile. Soy isolate is a highly refined yet complete plant protein, while whey is fast‑digesting and high‑leucine—together they cover quality and texture. It’s a strong protein showing versus most bars, powered by that soy‑plus‑whey combo.
Fat
69LOWAt 6.3 grams, fat is modest and comes mainly from palm and palm‑kernel oils in the white‑chocolate‑style coating. Those tropical oils are more saturated than fats from nuts or olive oil, but the total amount here is low. You get structure and a creamy bite without a heavy fat load.
Carbs
1720MIDMost of the 17 grams of carbs are engineered rather than from whole foods: soluble fibers and fiber‑like syrups provide bulk and bind, while the crispies’ starch and a touch of wheat flour add a little digestible carb. This mix generally hits blood sugar more gently than table sugar, though some isomalto‑oligosaccharides are partly digestible, so responses vary. Expect a steadier trickle of energy, with the caveat that higher loads of these refined fibers can bother sensitive stomachs.
Sugar
44MIDSugar stays low at 3.8 grams, largely from natural dairy lactose in the whey/milk ingredients rather than added cane sugar. Sweetness instead comes from a sugar alcohol (isomalt) for bulk plus a tiny dose of an artificial sweetener (sucralose), with soluble fibers contributing mild sweetness. That keeps blood sugar steadier than a sugary coating, though polyols can cause gas or bloating for some.
Calories
217210MIDAt 217 calories, this sits near the middle of the category, with protein and carbohydrate providing most of the energy and fat the smallest share. Rough math: about 80 calories from protein, ~57 from fat, and the rest from carbs (including lower‑calorie bulking sweeteners that bring texture with fewer calories than sugar). Satisfying, but not a calorie bomb.
Vitamins & Minerals
No standout micronutrients are listed above 10 percent Daily Value—this bar isn’t fortified. The tocopherol‑rich extract on the label is mixed vitamin E used as an antioxidant to protect the oils, not as a meaningful nutrient source. Dairy proteins may bring a little calcium naturally, but nothing jumps off the label.
Additives
This recipe leans on a handful of refined helpers: soluble fibers to bind and bulk, a sugar alcohol and sucralose to sweeten without much sugar, glycerol to keep it soft, lecithin to emulsify, and tocopherols to keep fats fresh. They’re effective and widely used, but they’re more processed than pantry‑style whole foods. If you prefer short, minimally processed ingredient lists, take note.
Ingredient List
Defatted soybean flakes
Sugar beet or cane sugar
Chicory root
glucose
Soybeans
Corn or tapioca
Vegetable oils and animal fats
Cow's milk
Sugar cane and sugar beet
Plant oils
What are people saying?
Sources
Range
“First time trying this one, and it’s become a favorite already! I love the new granola/puff type of protein bar! It’s so much different than the classic soft and chewy chocolate ones! I can definitely recommend this! Macros are on the last picture! I also are yet to try their Marshmallow White Chocolate and Nutty Caramel! 🤤🤤🤤”
“Just had the marshmallow crunch and it was excellent. Very different from most bars I've tried. Similar to fitness bars.”
“- Optimum Nutrition Marshmallow crunch. Tastes extactly like a marshmallow rice crispy bar with some white chocolate.”
Main Praise
Taste and texture lead the applause.
Multiple Redditors call Marshmallow Crunch “very different” in a good way—more like a puffed, granola‑meets‑Rice Krispies bar than the usual taffy‑like block—and one even said it tastes exactly like a marshmallow rice crispy treat with a touch of white chocolate.
Stack3d raves about the bite, noting your teeth “sink right through” as if it were a soft marshmallow. The protein number is strong for the category at 20g, and the overall calories stay moderate, so it feels like a treat without throwing off a day’s macros.
Sweetness is present but not syrupy, which some readers appreciate because it dodges that cloying, candy‑bar sugar rush. In short: it’s easy to eat, easy to enjoy, and it scratches a very specific craving most bars don’t even try to hit.
Main Criticism
Not everyone finds the flavor as bold as the name suggests. Independent reviewers and a few Reddit comments say the profile can read milder than “marshmallow white chocolate,” sometimes landing more as a gentle sweetness than a big flavor pop.
Because sweetness comes from isomalt (a sugar alcohol) plus a tiny dose of sucralose, sensitive stomachs may notice gas or bloating—one Reddit user put it bluntly: “My stomach did NOT like this at all.
” The ingredient list leans processed, with refined fibers for structure and palm‑derived oils in the coating, which won’t appeal to whole‑food purists. And since this variety includes wheat and soy, it’s a no‑go for gluten‑free or soy‑free eaters.
The Middle Ground
So which is it—marshmallow magic or marketing fluff? The truth sits between the poles.
If you like crispy cereal bars and prefer a lighter, less chewy bite, you’ll probably love this texture; that consensus spans Reddit and Stack3d’s deep dive on the lineup’s marshmallow‑soft feel.
The flavor, though, is intentionally restrained. Expect a nostalgic marshmallow‑cereal vibe, not a sugar‑bomb.
On the nutrition side, the low sugar is achieved with refined fibers (like fructo‑oligosaccharides and polydextrose) and isomalt for bulk, plus a sprinkle of sucralose for punch.
That combo helps keep blood sugar steadier than a typical candy coating, but it can bother some people’s digestion—especially if you inhale one on an empty stomach or pair it with other fiber‑sweetened snacks.
As for “5g net carbs” claims floating around older threads, it’s worth remembering that some of these fibers are partly digestible, so net‑carb math isn’t identical for everyone. Translation: great texture, measured sweetness, smart macro play—just know your tolerance and your allergens.
What's the bottom line?
Optimum Nutrition’s Marshmallow Crunch is a crowd‑pleaser for anyone who wants the fun of a rice‑crispy treat with real protein behind it. The 20g protein lands well, calories stay moderate, and the puffed‑cereal texture is refreshingly easy to eat. It’s not a whole‑foods bar, and it isn’t trying to be; the sweetness and structure come from refined fibers, a sugar alcohol, and a touch of sucralose.
If those sit fine with you and you’re not avoiding gluten or soy, this is a smart, satisfying swap for a nostalgic sweet. If, however, you want bold, candy‑bar flavor or you’re sensitive to polyols, you may find the taste too gentle or the digestion not worth the trade. Everyone else?
Keep one in your gym bag for post‑lift cravings or when a marshmallow mood strikes. Condensed listicle version: Crispy, marshmallow‑meets‑cereal bar feel with 20g protein and a mellow white‑chocolate finish.
Lower sugar thanks to fiber and isomalt, but that combo can bother sensitive stomachs. A great post‑workout or afternoon treat if you eat wheat and soy and want dessert energy without the sugar swing.