The reputation of carbohydrates greatly mirrors a Game of Thrones character: first they're good, then they're evil, then they're vindicated, then they're the devil. Let's sort out some of the confusion.
The demonisation of carbohydrates is something that I have been guilty of in the past. In fact, I spent about three years on and off on a carbohydrate-free ketogenic diet. But I was wrong.
Best-selling author and fitness expert, Adam Bornstein, explains that poor diet setup is one of the main reasons that carbohydrates are often demonised. Lots of people will cut carbohydrates from their diet, then lose weight rapidly due to their body's glycogen stores being depleted.
This isn't true long-term progress, however. In fact, completely cutting out carbohydrates is usually unsustainable. Once you re-introduce carbs to your diet, you'll re-gain weight, and the replenishment of glycogen may lead to bloatedness and/or feeling sick. The natural conclusion most people come to: carbohydrates are bad.
This confusion is exacerbated by the fact that carbohydrate "tolerance" varies from person to person at a physiological level. This tolerance depends on everything from insulin sensitivity, as Adam explains, all the way to genetic polymorphism.
The reality is that carbohydrates aren't inherently bad. In fact, if you have a proper exercise regimen, they may help you maintain a high level of energy. Of course, some people might be better with more carbohydrates, and some might be better with less. This is what you need to figure out to make your diet succeed: where do you lie on that spectrum?
I highly recommend checking out Adam's comprehensive explainer at the link below for a more in-depth look at carbohydrates, how they affect your body, and how to determine what kind of carb intake is best for you.