eli5 : Why do we gain a tolerance to consuming certain things but not for others?


Im mainly referring to caffeine like coffee or pre workout. After a while the effects of those will be less than the first time you take it but something like protein powder? How can you not build a tolerance towards it even after, for example, drinking a shake or two a day?

In: 4

Caffeine is a psychoactive drug. Your brain has receptors where caffeine molecules can fit (they’re supposed to be for the amino acid adenosine, but caffeine fits in there too, keeping you awake). So you create more and more receptors which means it takes more to get the same effect. That’s the short of tolerance. Protein powder is food which gets broken down by enzymes in your digestive tract. It never makes it to your brain/rest of your body in its original form the way a drug does.

Caffeine is a drug that directly stimulates receptors. Protein powder is just food. It’s not a drug with an effect.

You can’t have a tolerance to protein powder in the same way you can’t have a tolerance to donuts. I wish! But no, when you eat food, your body digests it. Evolutionarily speaking there’s never been a good reason to not digest and consume fuel that’s been eaten, so there’s no mechanism for that.