According to this fan theory, they might be!
Reddit-user thebeginningistheend suggests that Hobbits were once Men, only to be domesticated and bred by Elves. Kind of like what us humans did to the wolves back in the day. Once they were majestic beasts, and now we have pugs.
The theory might be a far stretch, but considering that no one really knows when or where Hobbits came from it can kind of make sense if you want it to. Besides, no one alive today can confirm or debunk the theory, so we may as well enjoy it.
So here's how it works
In The Silmarillion, there is a clear description of how Elves, Men and Dwarves came to be. But no such description exists for Hobbits, and their origins are unknown. One of the few things we do know about them is that they lived in a place called Anduin, and later on they traveled and settled in what we now know as The Shire.
Another race that lived in Anduin were the Wood Elves, and they were known for being somewhat reckless and less wise than their peers. So what if, at one point in time, the Wood Elves came in contact with Men, captured and domesticated them and bred them so they ended up looking like Hobbits.
Orcs and Servants
It wouldn't be the first time something like this happened, the Orcs were once Elves who were captured and tortured. If Elves can end up looking like Orcs, surely Men can end up looking like Hobbits.
Additionally, the Hobbits seem to share some qualities with the Elves, such as their love for wine, food, song, and friendship. And where the Elves are fit for ruling, the Hobbits are naturally subservient beings. After all, Merry and Pippin both pledged an oath to a foreign ruler and Sam followed Frodo on a suicide mission just because a wizard told him to do so. If you need a reminder of that, here's the clip of Pippin's song that he is singing because the Steward of Gondor told him to.
Elves and Hobbits seem to get along very well, just think about the fact that Frodo and Bilbo were allowed to sail with them to the Undying Lands, something which was very uncommon for other races to do.
The theory really is only speculation, but it's definitely an interesting thought and I for one would love to know more about the origins of Hobbits. If you'd like to read the original Reddit post, head on over to this link.