William Howard Taft lost his lease on the White House in the 1912 election, then lost 60 to 70 pounds and lived until 1930. (Bain News Service/Library of Congress)

Look, I get it. The Washington Nationals’ fourth-inning Presidents Race is a diversion, nothing more — a ballpark tradition, a chance for a belly laugh. A diversion from a diversion, if you think about it, for pro sports are supposed to be the kind of entertainment that relieves us of our daily burdens.

But if the Nats are preparing to use their newest mascot, William Howard Taft, the way I think they will, their fifth racing president is a terrible choice, especially for the thousands of children in the stands every night.

“They’re all rather large,” Andy Feffer, the team’s chief operating officer, said of the presidents, “but he will be a little bit larger.”

The lovable fat guy is a dangerous anachronism, one that should be discarded in our cultural dustbin, along with the sexy smoker and the affable drunk. Fat kills, as surely as speed did in the 1960s, only it happens more slowly and you suffer more.

Taft, the 340-pound chief executive, who was about 6 feet tall, may have had severe obstructive sleep apnea and very high blood pressure, according to one journal article. Both conditions improved greatly when he dropped 60 to 70 pounds within a year of leaving the White House after losing the 1912 election. He died, at 72, of heart disease brought on by fatty deposits that narrowed his arteries.

Taft will join George Washington, Thomas Jefferson, Abraham Lincoln and Theodore Roosevelt in the Nationals’ Presidents Race. (Susan Walsh/Associated Press)

In addition to sleep apnea, hypertension and heart disease, obesity-related problems include stroke, Type 2 diabetes, some cancers, liver and gallbladder diseases, respiratory diseases and arthritis, according to the Centers for Disease Control and Prevention. Two-thirds of Americans are overweight or obese; the government considers obesity one of the top two causes of preventable deaths in the United States, along with smoking. Perhaps 300,000 deaths a year are attributable to obesity.

I am not some finger-wagging scold or super-fit athletic trainer. If you’ve read my MisFits columns for the past four years, you know that I am aging, unathletic and, yes, somewhat overweight. I freely admit to an unhealthful diet. Two years ago, I tried out to be a racing president myself, just to see how difficult it is. It was not my finest hour.

Nor do I pretend to know what it’s like to suffer the indignities we heap on the obese in our society, or to finally have a fat guy to root for, as my colleague Michael Rosenwald, a self-described “fat guy,” wrote in The Post on Sunday.

But if you read my columns, you also know that I believe that any able-bodied person, of any age, can and should be engaging in some kind of regular physical activity. And that the benefits of doing so are enormous, in some cases life-changing.

So as Taft gets ready to literally run again, here are a few things I’d love to see the Nats do:

●Let him win. That’s right, make him a role model instead of a buffoon. Show us that he struggles with his weight, but he’s out there training, getting his 30 minutes of cardio a day, maybe more — at least enough to beat Tom, Abe, George and Teddy occasionally.

I’m not betting heavily on seeing this. The Nats humiliated Roosevelt — perhaps the fittest president between Washington and Bush II — for six years before they let him capture a Presidents Race. I can only imagine what they’ll do with Taft.

●Resist the gluttony gags. Yes, Taft indulged extravagantly. That was then. Now, even as meals everywhere continue to grow in size and number of calories, one of the best things we can do is control our portions. Do we have to start the season watching Taft downing a vat of Ben’s chili while the other presidents take off for the finish line?

●Don’t get him stuck in a bathtub. Apparently, this did happen to the poor man during his White House years. Can we avoid replaying it for the home crowd?

One encouraging sign is the surprisingly svelte Taft that the team introduced last month, a character so thin that many fans complained he did not match their image of the 27th president. Perhaps the Nats are going with a post-presidential Taft, 60 or 70 pounds slimmer after an effective diet.

Or perhaps they know that tens of thousands of impressionable kids will be watching.