Daniel Berlin: The Babson Senior Who Put Probiotics in a Chocolate Bar

The first thing you notice about Daniel Berlin’s chocolate company is the name, and he knows it. “You might not like the name, but you won’t forget it,” he told the Boston Globe this spring. DIRTY GUT, in capitals on a bag of individually wrapped chocolate bites, sounds like a dare. Inside are 10-gram pieces of dark or milk chocolate sweetened with coconut sugar, carrying two grams of prebiotic fiber and a billion live probiotic bacteria each. Berlin was 22 and a senior at Babson College when the Globe met him, a business student from Annapolis, Maryland who had already sold out his first production run, won his school’s biggest pitch competition, and put the bites on shelves in farm stands and specialty grocers from Massachusetts to Virginia. On March 31 the full line went on sale nationally online. It is the oldest trick in the new gut-health playbook, and one that Let Loose pulled with a pair of platform shoes in July: make people laugh at the package, then hand them something real.

The 40 poundsA sweet tooth that survived a diet

Berlin tells the origin story the same way every time, and it is not a gut story. It is a weight story. “I was overweight at 15 and 16,” he told the Globe. “I got rid of junk food and lost 40 pounds, but still had a sweet tooth.” The version on his company’s own site is blunter: “A few years back, I lost 40 pounds and realized something that changed the trajectory of my life: what you eat is everything.” What he could not find, once he had cleaned up everything else, was a chocolate that met the standard he was now holding the rest of his diet to. So he started making his own.

His argument for why that gap exists is a historical one, and he makes it with the confidence of a college senior. “For centuries, chocolate was valued as a healthy food,” he said in the company’s launch announcement. “It only became junk over the past 150 years. We’re bringing it back to its roots.” To Poets&Quants, which named the company one of 2025’s most disruptive business-school startups, he put it another way: “The chocolate our great-grandparents bought 100 years ago is the same we buy today: cacao, highly processed cane sugar, and a slurry of unnecessary additives.” The idea that followed was almost too simple. “I was like, why can’t we just combine probiotics in chocolate?” he said early last year, weeks before his first bar shipped.

The first companyMistakes, made early

DIRTY GUT is not Berlin’s first business. It is his second, and he is unusually candid about the first. In his senior year at the Severn School outside Annapolis, through a school fellowship program that lets students spend a year on an independent project, he built a sports-recovery supplement called Complete Recovery under a company he named Performance Backed. The pitch was that the recovery products he had been buying as a teenage athlete were mostly filler. “After reading the ingredients on some of these products, I realized I basically bought a bunch of worthless ingredients,” he told the school. The product launched in February 2023 and, by his own account, went nowhere. “I made a lot of mistakes,” he said, “from branding to developing the formula.”

That is a rarer admission than it should be from a founder, and it is more than a footnote: the company that sells DIRTY GUT today is, on paper, still Performance Backed LLC, doing business under the new name. He kept the vehicle and changed the cargo. The lesson he took from the supplement, that a product lives or dies on its formula and its label, is visible all over the chocolate.

The towerFour years in a dorm full of founders

Berlin arrived at Babson, the Wellesley, Massachusetts college that teaches almost nothing but entrepreneurship, already planning the business, and he has spent all four years living in eTower, a residence hall reserved for students running companies. “Everyone runs a business, from junk removal [to] food to tech,” he told the Globe. By the spring of his junior year he was its president. He credits professors by name, Brad Johnson, Vini Onyemah and Len Green among them, and a sales practicum run by an alumnus who is chief executive of a nutrition company. His first retail account, the farm stand Volante Farms in nearby Needham, is owned by another Babson graduate.

The turning point was a Friday night in April 2025. The B.E.T.A. Challenge is Babson’s annual pitch competition, and its finale that year, held April 11 in an auditorium in Olin Hall, offered a $25,000 grand prize in each of three tracks. Berlin took the undergraduate track for a chocolate bar formulated with prebiotics and probiotics, and a $10,000 alumni award on top of it, for a total of $35,000. He had, Babson noted, already sold out his initial production run. “You come to Babson to be an entrepreneur, and I think winning this is the pinnacle of being an entrepreneur at Babson,” he said that night. “So, I almost, in a way, feel like I completed my Babson journey by winning this tonight.” Asked what the money was for, he did not reach for a vision statement. “The main thing right now is I just don’t have enough money to scale. Now that I have this, I can go out and do my production run, get it in all the stores, partner up with distributors.” And then, the line that tells you how old he is: “To be able to come here and win and have all my friends from eTower and my mom here is so special to me.”

The month before the competition he had shipped his first bar into Boston-area stores. A year later the bar had become bites, three flavors, and a national online launch. His ambition has not been scaled down to match the size of the company. “My long-term goal with my startup is to take on Hershey’s,” he told Poets&Quants in January. “I want to be the modern chocolate brand that brings health and your gut back to the chocolate aisle.”

The biteWhat is actually in it

The company’s own framing, from its launch release, is the right place to start: “We didn’t start with a probiotic supplement and try to make it taste like chocolate. We started with delicious cocoa and crafted exceptional chocolate. Then we enhanced it with more fiber, less sugar, and live probiotics.” On the nutrition panels that translates to a Rich Dark bite of 10 grams at 50 calories, with 2 grams of fiber and 2 grams of sugar, all of it added; a Sea Salt Crunch bite, slightly smaller at 9 grams and 45 calories, with the same fiber and sugar plus a little crisp rice; and a Classic Milk bite, 10 grams and 50 calories, with 1 gram of fiber and 3 grams of sugar. The cocoa is sourced in Ghana, the sweetener is organic coconut sugar, and the milk version uses A2 milk powder, a form of dairy some people say they tolerate better. The two dark flavors are vegan.

The fiber is a blend of chicory root, acacia and cocoa fiber. The probiotics are named on the label as Lactobacillus rhamnosus GG, L. plantarum, Bifidobacterium lactis and B. breve, at a stated one billion live cultures per bite; the company recommends one to three bites a day. A bag holds eight, sold in stores for $7.99 and online only as a six-bag pack, currently $49.99. The store locator lists ten stockists, most of them farm stands and specialty grocers around Boston, with outposts in New York, New Jersey, Virginia and Florida. That is a small footprint, and an honest one.

What the research actually measuredA chocolate, read at its real size

No study of DIRTY GUT exists, and the company does not cite one. What exists is research on its parts, and it is worth reading at its actual size. The idea of chocolate as a delivery vehicle is not new: a 2010 laboratory study in a model of the human gut found that chocolate protected two probiotic strains through simulated digestion far better than milk did, with 80 to 91 percent surviving in milk chocolate against 20 to 31 percent in milk. Those were different strains from Berlin’s, and it was a lab model, not people, but the principle holds: fat and cocoa are a kind place for bacteria to travel.

The strains themselves are among the better-studied in the category. L. rhamnosus GG has a 2015 meta-analysis of 12 randomized trials behind it for preventing diarrhea during antibiotics, cutting the rate from about 22 to 12 percent, though the effect was clear in children and not in adults. For B. lactis, the dose question matters more than the name, and the numbers cut both ways for a one-billion bite. In a 1,248-person trial of the BB-12 strain, one billion a day improved how often people went as much as ten billion did. A smaller trial of the HN019 strain shortened gut transit time at 1.8 billion a day. But a later HN019 trial at one and ten billion found no difference on its main outcomes, and the Cochrane review of probiotics for antibiotic-associated diarrhea in children found doses of five billion a day and up worked better than lower ones. Read together: one to three bites a day sits at the floor of the doses that have shown anything, not in the middle.

The fiber is the same story in miniature. Two grams is the whole blend, not two grams of inulin, and the trials that moved gut bacteria used more: a 2007 trial, pleasingly, delivered its inulin in a chocolate drink, and found 5 grams a day was enough to raise bifidobacteria, while an earlier dose-ranging study found 2.5 grams a day was not. Three bites is six grams of mixed fiber, which is a real contribution to a day, roughly a fifth of the 28-gram target on the label, and a fair distance from a fiber supplement. For a sense of where you stand, our fiber calculator does the arithmetic; for the difference between what fiber and probiotics each do, see our explainer.

Our read: this is a good low-sugar chocolate with a genuinely thoughtful formula, made by someone who reads labels for a living, and that is the honest reason to buy it. The gut benefits are plausible and unproven, and the company’s own site reaches further than the evidence does in places, which is common in the category and which we have not repeated here. Anyone with ongoing digestive symptoms should treat a chocolate as a chocolate and start with their own doctor.

The disclosure mapWhere his interests sit

Berlin is the sole founder of DIRTY GUT and profits from its sales; the company is privately held, and the prize money and retail details in this piece come from Babson, the Boston Globe and the company’s own materials. He is a business student, not a clinician, dietitian or food scientist, and his account of losing weight as a teenager is his own experience, not advice. The nutrition figures are the brand’s stated values from its panels, which we have not independently tested. Gut Health Times has no commercial relationship with DIRTY GUT and was not sent product. This profile is educational, is not medical advice, and was prepared without input from the company.