Harry x Luna x Hermione x Harem?

Messing with the fabric of time ALWAYS has consequences, 99% of them making no sense at all.

Meeting in 4th Year instead of 5th, Harry Potter, a confused obese Hermione Granger enjoy an overweight Luna Lovegood's company, both girls ignoring what everyone is saying about them, save Harry, who stays quiet but looks upon their forms with love.

Later in the month, the trio happen upon The Room of Requirement, where the trio figure out during 3rd Year, Harry and Hermione use of the Time Turner put their consciousness, along with Luna's, into alternate versions of themselves, one where the two girls are the first carriers of The Munchies, a female magical disease that causes the host to continously gain weight with no known cure, with non-magicals unknowing, which starts at age 11.

Come The Tri-Wizard Tournament, Harry is ostracised by Hogwarts after being unwilling entered, save Hermione and Luna, who, after a long emotional talk, start a three way relationship.

As the weeks pass, and female pounds are gained, not by just Hermione and Luna, the trio must handle Dumbledore's machinations, Ron eating both of the girls food, heartbroken girls, divorced women seeking love, and the looming threat of Voldemort, though he isn't that important in the grand scheme of things.

TLDR: The minds of Canon Harry, Hermione and Luna are placed into a timeline where both girls start The Munchies, a weight gain disease that affects only female magicals, which has them start a three way relationship while the local witches, both single and divorced, flock to Harry in hopes of romance while Dumbledore schemes, Voldemort plots domination and Ron eats food that belongs to Hermione and Luna.