The Ingredient You Don’t Want in Your Protein Bar: Esterified Propoxylated Glycerol (EPG)
When you’re tearing into a protein bar, you’re doing it for one of two reasons: to fuel muscle gains or support fat loss. What you’re not doing is signing up for a chemistry experiment with your gut. But that’s exactly what you’re risking if your bar contains Esterified Propoxylated Glycerol (EPG)—an artificial fat replacer that’s quietly slipped into more and more “health” bars.
Let’s break down what EPG really is—and why serious athletes and bodybuilders should avoid it at all costs.
Esterified Propoxylated Glycerol (EPG) is a synthetic, modified fat used as a low‑calorie fat replacer in many high‑protein bars. Scientifically engineered to be poorly digestible—offering roughly 0.7 kcal per gram compared to the 9 kcal in natural fats—it mimics creaminess and texture without the calories. However, that “benefit” often comes at the cost of uncomfortable gastrointestinal symptoms, such as oily stools, cramps, and diarrhea, especially when consumed in larger amounts. Instead of resorting to chemical shortcuts like EPG, it’s worth reaching for clean, transparent nutrition, like Muscle Up Bars. Made with organic sweet potato, grass‑fed whey, nut butters, cacao nibs, and no sugar alcohols or artificial fillers, Muscle Up Bars deliver real flavor and gut‑friendly fuel without compromising your health. Try their Cacao + Vanilla flavor and feel good about what’s fueling your workout—and your gut.
What Is EPG?
Esterified Propoxylated Glycerol (EPG) is a synthetic fat substitute developed to provide the mouthfeel of fat without the calories. It’s made by chemically modifying glycerol (the backbone of triglycerides) through a process called propoxylation, then esterifying it with fatty acids.
Sounds delicious, right? Didn’t think so.
This Frankenstein fat isn’t digested the same way real dietary fat is. In fact, it’s specifically engineered to be poorly absorbed in the digestive tract, which is how it reduces calorie intake. Think of it as the Olestra of the 2020s—but with fewer warning labels and far less transparency.
How Is EPG Made?
Let’s geek out for a sec:
- Propoxylation – Glycerol is reacted with propylene oxide, a petroleum-derived chemical, to form propoxylated glycerols.
- Esterification – These modified molecules are then reacted with long-chain fatty acids (often from soybean or palm oil) to mimic the texture of real fat.
The result? A lab-made fat-like substance that can replace up to 85% of the fat in a product—with fewer calories.
But here’s the kicker: it doesn’t get absorbed well. That’s literally its selling point. But your digestive system might not appreciate that trick.
Side Effects of EPG
Since EPG isn’t fully absorbed, it can lead to gastrointestinal issues—particularly if you’re consuming more than one bar a day (which most bodybuilders do).
Common side effects include:
- Stomach cramping
- Bloating
- Loose stools
- Greasy, oily bowel movements
- Nausea
These aren’t hypotheticals—they’re straight from real consumer reports and FDA petition responses. In some users, EPG may also interfere with the absorption of fat-soluble vitamins like A, D, E, and K.
So you’re trading some calories for… what, exactly? A compromised digestive system and less nutrient absorption?
Which Protein Bars Contain EPG?
While not all brands openly disclose EPG on the front label, you’ll find it in the ingredients list of certain mass-market protein and energy bars, especially those branded as “low calorie” or “keto-friendly with indulgent taste.” Watch out for:
- “SlimFast Keto Fat Bombs”
- Quest Frosted Cookies
- Think! Bars (select varieties)
- Other “functional foods” with suspiciously low fat but creamy texture
Look for “EPG,” “esterified propoxylated glycerol,” or even vague descriptions like “fat replacer” or “engineered fat” in the fine print.
What Should You Eat Instead?
You want performance nutrition—not experimental fat substitutes. If you’re after real results, your post-workout fuel should come from clean sources of protein, real carbs, and healthy fats.
At Protein Factory, we don’t use shortcuts. No EPG. No fillers. No gimmicks. Just real protein, scientifically sourced and transparently labeled. Whether it’s native whey from milk or hydrolyzed peptides for ultra-fast absorption, our ingredients are chosen to build muscle—not bloat your gut.
Bottom Line
EPG is a lab-engineered, low-calorie fat substitute with questionable side effects and zero performance benefits. If your protein bar has it, it’s time to toss it. You train hard—don’t undo your gains with trash ingredients disguised as “innovations.”
Choose clean. Choose honest. Choose Protein Factory.
Notable Protein Bars with EPG
1. David Protein Bars
– Widely recognized for their 28 g protein / 150 calorie macro ratio, David Bars prominently use EPG as a fat replacer in their “fat system” alongside coconut oil modernretail.co+15dairyprocessing.com+15fda.gov+15.
– The EPG is derived from modified rapeseed (canola) oil—turned into a saturated, non-digestible form providing texture without calories popsugar.com+1vegnews.com+1.
2. Own Your Hunger “Wonder Squares” & Spreads
– Own Your Hunger is one of the smaller brands along with Lighten Up and Defiant that built their entire business model around EPG. All their flagship products, including high-protein bars and reduced-calorie nut spreads, contain EPG fda.gov+14cheatdaydesign.com+14dailydot.com+14.
3. Defiant Foods’ High‑Protein Chocolate Bars
– Defiant Foods also relies on EPG in their protein-packed chocolate bars. The recent acquisition by David Protein cut off this supply, prompting legal action agfundernews.com+10cheatdaydesign.com+10modernretail.co+10.
4. Nick’s Light Ice Cream
– Nick’s, known for low-sugar and low-cal options, uses EPG in their ice cream formulations to reduce fat while retaining creaminess sciencedirect.com+13cheatdaydesign.com+13snaxshot.com+13.
5. Legendary Foods – Sweet Rolls
– The brand incorporates EPG in their protein- and fiber-rich sweet rolls, again to cut calories without compromising texture .
6. Gatsby Chocolate
– This chocolate bar brand made waves on Shark Tank and also uses EPG as a fat substitute in its formulation cheatdaydesign.com.
Why It’s Widespread
- EPG provides fat mouthfeel while being nearly non-digestible (just 0.7 cal/gram vs. 9 cal for real fat) agfundernews.com+4agfundernews.com+4cheatdaydesign.com+4.
- It earned GRAS status for use in a variety of foods including baked goods, confections, and bars cheatdaydesign.com+14en.wikipedia.org+14epogee.com+14.
- Most high-protein, low-calorie products aiming for indulgent textures have used or still use EPG—until David Protein’s acquisition dramatically restricted broader access.
Industry Impact & Supply Crash
- David Protein’s purchase of Epogee (the sole manufacturer of EPG) in May 2025 secured exclusive supply and halted new orders for competing brands epogee.com+14agfundernews.com+14modernretail.co+14.
- As a result, many smaller brands—including Own Your Hunger, Lighten Up Foods, and Defiant Foods—have been forced to discontinue products that relied heavily on EPG cheatdaydesign.com+6agfundernews.com+6dailydot.com+6.
- This control has triggered antitrust lawsuits alleging monopolization and “bait-and-switch” tactics dairyprocessing.com+3agfundernews.com+3vegnews.com+3.
Consumer & Nutrition Expert Notes
- Dietitian Kim Yawitz notes EPG gives David Bars their soft texture but warns that higher doses (25–40 g) have caused diarrhea and greasy stools in a 2014 study cheatdaydesign.com+3popsugar.com+3vegnews.com+3.
- Reddit users describe EPG as “modified plant fat that’s intentionally indigestible,” and praise David Bars for their macros while noting concerns about ultra‑processed ingredients modernretail.co+3reddit.com+3cheatdaydesign.com+3.
Summary Table
| Brand / Product Type | Role of EPG | Status Now |
|---|---|---|
| David Protein Bars | Key fat substitute for soft, low‑cal bars | Active use; owns Epogee |
| Own Your Hunger (Wondersquares) | Core ingredient in bars & spreads | Discontinued due to EPG supply cut-off |
| Defiant Foods Chocolate Bar | Provides texture without calories | Bar halted; suing for access |
| Nick’s Ice Cream | Reduces fat calories in low‑fat ice cream | Previously used; supply uncertain |
| Legendary Foods Sweet Rolls | Adds creaminess with low calories | Previously used; future unclear |
| Gatsby Chocolate | Used EPG in formulation pre-acquisition | Supply now affected |
Final Takeaway
If you’re seeking high-protein, low-calorie bars with a creamy, satisfying texture, EPG has been a go-to for many brands—especially David, Own Your Hunger, Defiant, Nick’s, Legendary, and Gatsby. However, following David Protein’s acquisition of Epogee, the landscape has shifted dramatically: certain small brands have lost access to EPG, and existing formulas may soon be reformulated or discontinued.
Looking for a Cleaner Swap? Try Muscle Up Bars
Tired of artificial fat substitutes like EPG hiding in your protein bar? Muscle Up Bars offer a clean, transparent alternative that delivers on taste and nutrition—without the digestive drama:
- Made with USDA‑organic sweet potato, grass‑fed whey protein, organic nut butters, and cacao nibs, with zero EPG, sugar alcohols, stevia, or sucralose reddit.com+8muscleupbars.com+8amazon.com+8.
- They promise “no chemical aftertaste” and clean results—your gut will thank you muscleupbars.com.
- Each bar delivers ~15–16 g of protein and just 8 g of sugar—more protein than sugar, and none of the processed fat substitutes self.com+10muscleupbars.com+10amazon.com+10.
As their website states: “Most protein bars are loaded with sugar alcohols, artificial flavors, and processed fillers … Ditch the fillers. Choose real food.” muscleupbars.com
Alex Rogers is a supplement manufacturing expert. He has been formulating, consulting, & manufacturing dietary supplements since 1998. Alex invented protein customization in 1998 & was the first company to allow consumers to create their own protein blends. He helped create the first supplement to contain natural follistatin, invented whey protein with egg lecithin, & recently imported the world’s first 100% hydrolyzed whey.
