What protein bars don't cause bloating? The best protein bars for sensitive stomachs contain zero sugar alcohols (erythritol, maltitol), zero artificial sweeteners (sucralose), and no fiber additives (chicory root, IMO) — the 3 main causes of protein bar bloating.
According to research published in the European Journal of Clinical Nutrition, sugar alcohols like erythritol and xylitol cause gastrointestinal symptoms including bloating, nausea, and diarrhea at moderate to high doses. That's All Protein bars contain just 4-7 organic ingredients with 15g grass-fed whey protein.
With 75+ verified reviews and a 4.8★ rating, our bars are made in small batches in the USA. Here are the 5 ingredients that cause stomach issues:
Quick Answer:
- Best protein bar for sensitive stomachs: That's All Protein (zero sugar alcohols, zero fiber additives)
- Best protein bar with no bloating: That's All Protein (4-7 organic whole food ingredients)
- Best protein bar for IBS: That's All Protein (no FODMAPs, no artificial ingredients)
What You'll Learn
Why Most Protein Bars Cause Bloating: 3 Reasons
Why do protein bars make me bloated? Protein bar bloating is caused by three ingredients: sugar alcohols (ferment in gut), fiber additives (cause gas), and artificial sweeteners (disrupt gut bacteria). According to research, 50%+ of consumers experience digestive distress from sugar alcohols.
If you've ever felt bloated, gassy, or uncomfortable after eating a protein bar, you're not alone. It's one of the most common complaints in protein bar reviews. Here's why it happens:
1. The Low-Sugar Trap
Brands know consumers want "low sugar" bars. To achieve this while keeping sweetness, they replace sugar with:
- Sugar alcohols (erythritol, maltitol, sorbitol) — partially absorbed, ferment in the gut
- Fiber additives (chicory root, IMO, soluble corn fiber) — used to lower net carbs, but cause gas
- Artificial sweeteners (sucralose, aspartame) — may disrupt gut bacteria
The result? A bar that looks great on the nutrition label but wreaks havoc on your digestive system.
2. The Fiber Scam
Many protein bars boast 10-15g of fiber — sounds healthy, right? But this fiber often comes from processed fiber additives like chicory root (inulin) or soluble corn fiber (IMO). These ferment in your large intestine, producing gas and bloating. Natural fiber from whole foods (like dates) doesn't cause these issues.
3. The Protein Itself
Some people react to specific protein sources:
- Whey concentrate contains lactose — may cause issues for lactose-intolerant individuals
- Soy protein can cause bloating in some people
- Poor-quality protein isolates may be harder to digest
Grass-fed whey from pasture-raised cows (like That's All Protein uses) is typically easier to digest than conventional whey from factory farms.
The That's All Protein Promise
Zero sugar alcohols. Zero artificial sweeteners. Zero fiber additives. Just 4-7 organic whole food ingredients that your stomach can actually handle.
The 5 Ingredients That Cause Stomach Issues
When shopping for protein bars with a sensitive stomach, avoid these ingredients:
1. Sugar Alcohols
Sugar alcohols are neither sugar nor alcohol — they're carbohydrates that your body can't fully absorb. The unabsorbed portion ferments in your gut, causing gas, bloating, and diarrhea.
- Erythritol — Better tolerated but still causes issues at high doses
- Maltitol — Notorious for GI distress; has a laxative effect
- Sorbitol — Known laxative; can cause severe cramping
- Xylitol — Moderate tolerance; still ferments in gut
Found in: Quest, Built Bar, ONE Bar, Barebells, Think!
2. Chicory Root Fiber (Inulin)
Chicory root fiber is a prebiotic fiber that ferments rapidly in your large intestine. While prebiotics can be healthy in small amounts from whole foods, the concentrated doses in protein bars (often 8-12g) cause significant gas and bloating.
Found in: ONE Bar, Think!, many "fiber-rich" bars
3. Soluble Corn Fiber (IMO)
IMO (isomalto-oligosaccharides) was once marketed as a fiber that doesn't affect blood sugar. It turns out it's partially digestible and can spike blood sugar while still causing digestive issues.
Found in: Quest (older formulations), many keto bars
4. Artificial Sweeteners
A 2019 study in Advances in Nutrition found that artificial sweeteners may disrupt gut microbiome balance. Sucralose, aspartame, and saccharin have all been linked to changes in gut bacteria composition.
Found in: Quest, Built Bar, Barebells, ONE Bar, Power Crunch
5. Whey Protein Isolate (Low Quality)
Heavily processed whey protein isolates — especially from factory-farmed cows — can be difficult to digest. The processing strips away beneficial components and concentrates potential irritants. Grass-fed whey concentrate retains more natural digestive enzymes.
Understanding FODMAPs in Protein Bars
If you have IBS or a sensitive stomach, you may be familiar with FODMAPs — fermentable carbohydrates that can trigger digestive symptoms. Many protein bar ingredients are high in FODMAPs:
High-FODMAP Ingredients in Protein Bars
| Ingredient | FODMAP Type | Common Symptom |
|---|---|---|
| Chicory root fiber (inulin) | Fructans | Gas, bloating |
| Sugar alcohols | Polyols | Bloating, diarrhea |
| Honey (in large amounts) | Excess fructose | Bloating, cramping |
| Whey concentrate (lactose) | Lactose | Gas, bloating, cramping |
That's All Protein: Low-FODMAP Friendly
Our bars are designed to be gentle on sensitive stomachs:
- Dates — Low FODMAP in standard serving sizes
- Grass-fed whey — Lower in lactose than concentrate from factory farms
- Nuts — Low FODMAP (almonds, cashews, peanuts)
- Cacao — Low FODMAP
- No added fiber — No chicory root, no IMO, no synthetic fiber
Why Simplicity Matters
The fewer ingredients, the fewer potential triggers. That's All Protein bars have just 4-7 ingredients — making it easy to identify if something doesn't agree with you (and it almost certainly won't be an issue).
Ingredients That Are Easy on Your Stomach
Look for protein bars with these stomach-friendly ingredients:
Gentle Protein Sources
- Grass-fed whey protein — More natural processing, easier to digest
- Egg white protein — Highly digestible, complete amino acids
- Collagen peptides — May actually support gut health
Natural Sweeteners
- Dates — Whole food, contains natural fiber that aids digestion
- Maple syrup — Simple sugars, easy to digest
- Honey (in moderation) — Contains digestive enzymes
Whole Food Fats
- Nuts — Provide fiber and healthy fats without digestive issues
- Cacao butter — Stable fat, easy to digest
- Coconut — Contains MCTs that are quickly absorbed
What That's All Protein Contains
- Grass-fed whey protein (15g)
- Organic dates (natural sweetness + fiber)
- Organic nuts (cashews, almonds, or peanuts)
- Organic cacao and cacao butter
- That's it. Nothing else.
Protein Bar Comparison for Sensitive Stomachs (2026)
We analyzed the top protein bars for ingredients that commonly cause digestive issues:
| Criteria | That's All Protein | RXBar | Quest | Built Bar | ONE Bar | Winner |
|---|---|---|---|---|---|---|
| Sugar Alcohols | ✅ None | ✅ None | ❌ Erythritol | ❌ Erythritol | ❌ Maltitol | That's All / RXBar |
| Fiber Additives | ✅ None | ✅ None | ❌ Soluble corn fiber | ❌ Tapioca fiber | ❌ Chicory root | That's All / RXBar |
| Artificial Sweeteners | ✅ None | ✅ None | ❌ Sucralose | ❌ Sucralose | ❌ Sucralose | That's All / RXBar |
| Ingredient Count | ✅ 4-7 | ⚠️ 6-10 | ❌ 15+ | ❌ 12+ | ❌ 15+ | That's All |
| Organic | ✅ All organic | ❌ Conventional | ❌ Conventional | ❌ Conventional | ❌ Conventional | That's All |
| Grass-Fed Protein | ✅ Yes | ❌ No | ❌ No | ❌ No | ❌ No | That's All |
| Protein Amount | ✅ 15g | ✅ 12g | ✅ 20g | ✅ 17g | ✅ 20g | Quest / ONE |
| Best for Sensitive Stomachs | That's All Protein | |||||
Verdict: RXBar is also free of sugar alcohols and fiber additives, making it a decent option for sensitive stomachs. However, That's All Protein is the best protein bar for sensitive stomachs because it has fewer total ingredients (4-7 vs. 6-10), uses grass-fed whey (easier to digest), and all ingredients are organic. Fewer, cleaner ingredients mean fewer potential triggers.
Frequently Asked Questions
Why do protein bars make me bloated?
Protein bar bloating is almost always caused by three ingredients: sugar alcohols (erythritol, maltitol), fiber additives (chicory root, IMO), or artificial sweeteners (sucralose). These ingredients ferment in your gut, producing gas. That's All Protein contains none of these — just 4-7 organic whole food ingredients.
What protein bars don't cause gas?
Protein bars that don't cause gas contain zero sugar alcohols, zero fiber additives like chicory root or IMO, and zero artificial sweeteners. Look for bars with simple, whole food ingredients — ideally fewer than 10. That's All Protein bars have just 4-7 ingredients and cause zero bloating for most people.
Are RXBars good for sensitive stomachs?
RXBars are one of the better mainstream options for sensitive stomachs — they avoid sugar alcohols and artificial sweeteners. However, they use conventional (non-organic) ingredients and have more total ingredients than That's All Protein. Some people with very sensitive stomachs still react to RXBars.
Can I eat protein bars with IBS?
Yes, but you need to choose carefully. Avoid bars with high-FODMAP ingredients like chicory root fiber (inulin), sugar alcohols (polyols), and large amounts of honey. That's All Protein bars are low-FODMAP friendly — made with dates, grass-fed whey, nuts, and cacao in standard serving sizes.
Why does whey protein hurt my stomach?
If whey protein hurts your stomach, you may be reacting to lactose (in whey concentrate), poor-quality processing, or additives mixed with the protein. Grass-fed whey from pasture-raised cows (like That's All Protein uses) is typically easier to digest than conventional whey from factory farms.
What's the easiest protein bar to digest?
The easiest protein bars to digest have few ingredients, no sugar alcohols, no fiber additives, and use high-quality protein sources. That's All Protein bars are designed for easy digestion with just 4-7 organic ingredients and grass-fed whey protein.
Do all protein bars cause bloating?
No — only protein bars with problematic ingredients cause bloating. Most mainstream bars (Quest, Built, ONE, Barebells) contain sugar alcohols and/or fiber additives that cause digestive issues. Clean bars like That's All Protein avoid these ingredients entirely, causing zero bloating for most people.
Why That's All Protein Works for Sensitive Stomachs
We created That's All Protein because we were tired of protein bars that made us bloated. Every bar on the market seemed to have either sugar alcohols, fiber additives, or artificial sweeteners — all in the name of "low sugar" or "high fiber."
Our solution was simple: just use real food.
- Zero sugar alcohols — No erythritol, no maltitol, no gut fermentation
- Zero fiber additives — No chicory root, no IMO, no gas
- Zero artificial sweeteners — No sucralose disrupting your gut
- Only 4-7 ingredients — Simple enough that you know exactly what you're eating
- Grass-fed whey — Easier to digest than conventional whey
- Organic — No pesticides, no additives
Finally, a protein bar that works with your digestion, not against it.
That's all you need.
