Diet Coke packs about 46 mg of caffeine per can. That’s roughly half a cup of coffee. Caffeine is known to stimulate stomach acid production, like turning up the heat under a pot of water.
But here’s the twist: not everyone reacts the same. Some people can down three cans and feel fine, while others get heartburn from one sip. Your body’s chemistry is a unique snowflake, and so is its relationship with caffeine.
Artificial Sweeteners: The Wild Card
Ah, aspartame. That’s the sweet stuff in Diet Coke. Some folks claim it triggers reflux, but science isn’t fully convinced. A 2026 review in the journal Nutrients found no strong link between artificial sweeteners and acid reflux for most people.
List of 12 Foods That Cause Acid Reflux Symptoms
However, plastic taste aside, your gut microbes might throw a party or a tantrum. Everyone’s microbiome is like a fingerprint—unique and sometimes dramatic. If aspartame upsets your gut, it could indirectly promote reflux, but it’s not a guaranteed firestarter.
