Ed Sheeran says he will do a "Carpool Karaoke" for "The Late, Late Show" with James Corden. But (and this is a really big but) he's bringing some "Big Booty Hoes" to raunch up the sketch. The "Thinking Out Loud" singer is thinking up lewd tweaks to Corden's famous skit. The bigger question however, is how that 56-lb weight loss is going on Sheeran's infamous vodka diet.

Could Ed Sheeran's vodka diet work?

In arguably the weirdest diet tip ever, "The Late, Late Show" guest said he gave up drinking beer. What's so odd about that food swap? It's not what Sheeran isn't drinking, but what he is.

The "Thinking Out Loud" artist swapped the brews for vodka and proclaims to have lost 35 pounds. The blog Diets in Review analyzed this claim and concluded that if he was swapping equal quantities he would take in six times the calories with vodka. But liquor is served in 1.5 ounce shots which contain 90 calories for 80-proof. Even Bud Light has 110-130 calories. It's not big calorie savings, but if you also cut quantity--two shots a day instead of six beers, for example--it adds up.

Ed Sheeran big weight loss an eating disorder?

The Daily Mail quoted the artist as saying he shaved off four stone (British) which equals 56 pounds. Sheeran admitted that at one point, he weighed 15 stone (or 210 pounds).

For a man of shorter stature that would put Sheeran in the obese category on the BMI (body mass index). But in 2015, he dropped down to 11 stone (or 154 pounds). So while 210 equals obesity, 154 nears underweight. The British crooner probably doesn't have anorexia, a common concern in big weight loss. With the Daily Mail interviewer, he ordered Subway and was hardly calorie counting.

Ed Sheeran maintains 56-lb weight loss?

Getting a lot of weight off may seem like the hard part. Shedding obesity is no easy feat, certainly, but it's much easier than maintaining the new body. Often after massive weight loss, folks navigate the maintenance diet part not as well. The pendulum swings the other way and pounds creep back on.

If it's only 10-20, it's usually okay. But statistics say many people gain back about half of what they took off. In interviews for the James Corden sketch, it appears Sheeran may have done this. But if folks take weight loss too far or have an eating disorder, return weight gain is healthy.