Observe; Don't Engage
As you grow wiser, you learn when to engage in an ongoing conversation and when to observe without engaging.
Consider the following case: someone started to make erroneous claims and false statements, such as “most energy drinks have zero calories.” He/She is directing the conversation towards you. Now you can begin to correct him/her, or you can listen without agreeing or disagreeing and act as if learning something new. Which approach would you adopt?
The natural reaction is politely disagreeing and trying to summon scientific evidence that contradicts their statement. For instance, you can look up the number of calories in well-known energy drinks. Should you do that?
If the other person would listen and learn new facts, then you most definitely should proceed to inform them of related facts. The purpose would be for them to change their stance. However, if you know beforehand that they won’t change their opinion no matter what piece of evidence you can show, then the wiser choice would be to “observe” and not “engage” in a pointless debate.