Ever since I was a little kid I’ve been anxiously awaiting the day when human beings would start evolving into Bigheads. Futurists and science-fiction writers have long predicted that, when technology relieved us of the need to perform physical labor, we’d turn into superintelligent creatures with massive craniums atop spindly little bodies. As a devoted cinéaste, I naturally figured that 2001 would prove a breakthrough year in this development, but I’ve done the math, and it’s not our heads that are getting bigger. It’s our butts.

And our guts, along with every other part of our anatomy capable of ballooning up to record-breaking tubbiness. That’s how you know we really haven’t been visited by aliens from outer space. If human evolution is any yardstick, they wouldn’t have looked like E.T. or the creatures in Mars Attacks! or Independence Day. They would have looked like Al Roker. And, so far, I haven’t seen anything like that on “The X Files.”

You can’t turn on a TV without being bombarded by the statistics. Men, women and children in this nation are getting more mammoth by the minute. And, as Americans, we’ve responded to the problem in our own inimitable fashion: Rather than improving our dietary habits or getting regular exercise, we’ve come up with ways to integrate flab into the matrix of fame and fortune.

The land of the fat has developed whole new ways to live off the fat of the land. There are the obvious examples, such as the boom in sales of over-the-counter treatments for gas, bloating, flatulence and heartburn. What was once a simple plop, plop, fizz, fizz has swelled into a tsunami of pharmaceuticals promising relief from the effects of eating too much, too fast, the foods we shouldn’t be eating at all.

These remedies used to be pills we turned to for help after overdoing it. But, as Jerry Seinfeld once marveled in his show, medications are marketed today to ingest in advance of experiencing symptoms of distress. Medicine, evidently, for people who are planning to be sick and would rather medicate preemptively than simply eat properly.

There are the infomercials for exercise machines — everything from home gyms, treadmills and Nordic Traks to an apparently endless variety of ab-building contraptions engineered by leading scientists like Suzanne Somers and Chuck Norris.

There are ads for national fitness centers and diet books. And then there’s Richard Simmons, a booming, bizarro TV industry unto himself. In what other country could a guy this out of control, this gigglingly unhinged and, let’s not forget, plump strike it rich as an icon of self-control?

And, of course, there are the more traditional, non-sweating-to-the-oldies-based weight-loss programs like Optifast, NutriSystem and Jenny Craig. From Halloween through Thanksgiving, right up to the moment Dick Clark drops that ball in Times Square, the airwaves are stuffed with ads for holiday candies, hams, turkeys and desserts. Then, suddenly, they make way for an onslaught of diet-system ads bringing us the news that we’ve been pathetic gluttons for the past few months and the time has come to shape up.

No wonder the economy has been so strong. Think of the billions generated each year just through this orchestrated see-saw of bingeing and abstinence. What I find more interesting, though, are the subtle ways in which our increasingly porky culture has recalibrated feelings about fat, and how those shifts have come to be exploited in the pursuit and maintenance of celebrity.

In the old days, as you may have heard, one actually had to accomplish something to earn fame. Think Charles Lindbergh, Babe Ruth, Pablo Picasso, Ernest Hemingway. The bar has been lowered steadily over the last half-century, however. Today, the simple fact that a person has controlled their weight can make the difference between being famous and being forgotten.

Take the case of Ricki Lake. She built a daytime talk dynasty on the fact that she’d once been obese and funny-looking but managed to diet her way down to twentysomething perkiness. Sure, the format for her show played a part in her success, but clearly, she never would have spent a minute in front of those cameras if she hadn’t shed those pounds.

The problem with basing your fame on your waistline: What happens if you re-chub? In Lake’s case, she’s adopted the philosophy, “If you can’t beat ’em, join the cast of a show about a lardbucket.” She now costars on CBS’ “The King of Queens” as stocky Doug Heffernen’s stocky younger sister. She’s on the blubber border, though. A few more pounds and America may not find her so funny.

Just ask Delta Burke about that. Remember what happened to her? The former beauty queen packed on a few too many pounds and got heat from both her network and the producers of her hit show, “Designing Women.” She blamed the usual suspects — a bad metabolism, a problem with diet pills, etc — but disappeared from the spotlight anyway. Until recently, when she reappeared at a drastically reduced weight in the new sitcom, “DAG.”

But who’s got time to slink off and quietly drop a hundred pounds in today’s fast-paced, media-driven world? The examples of Lake and Burke seem quaint next to that of overinflated chanteuse Carnie Wilson, who decided to make her reduction in size itself a return to the limelight, rather than merely a prelude to it, by having her stomach surgery simulcast on the Internet. Lights, camera, rib retractors — now that’s entertainment!

Today Wilson is relatively svelte and newly married. It’s odd, though, that whenever I see her interviewed on TV, everyone just says, “Oh, doesn’t she look great!” No one ever says, “My God, she couldn’t stop eating and the only way she could lose weight was to have a doctor sew her stomach shut, and she thought that was something millions of people would want to watch? She makes her father look like Ozzie Nelson.”

Take Richard Hatch. Please. The smarmy “Survivor” champ always seems to be described on television in terms of his cunning, intellect and sense of control. Every now and then someone mentions the fact that he used to weigh almost 400 pounds, but no one ever says, “So, Rich, where was all that control when you were closing in on 400 pounds? Were you hoping to make your TV debut as one of those naked fat guys Jerry Springer has to forklift out of their house?”

Have we become so superficial that we actually look at someone like Hatch, congratulate him for being in better shape, and never question the character and thought processes responsible for his putting on hundreds of pounds in the first place?

Well, yes. Simply losing weight has come to be viewed as an accomplishment ranking with the noblest works of humankind — an ipso facto, no questions asked, goes-without-saying good thing, meriting the attention and approval of all.

Just ask Oprah. She never tires of taking credit for taking off a pound or two, telling the world how she did it, how everyone else should do it, too, walking around for a year or so like the high priestess of mental health and political correctness before blimping out and beginning the cycle all over again.

Have you seen those Subway spots featuring former load Jared Fogel? In the “before” shot the guy weighs an easy 350 pounds. In the “after” photo he’s slimmed down, we’re told, through a combination of taking walks and eating lots of low-fat submarine sandwiches. Have we become so gullible that we actually believe submarine sandwiches are an important part of an effective weight-loss program? Well, yes. Apparently viewers are just so dumbstruck by the fact that the kid dropped so much weight, the wackiness of the ad’s premise doesn’t register. The campaign has been a huge success, so to speak.

I realize Fogel isn’t technically a celebrity — not yet, anyway — but I just find the idea of a grinder-based diet plan so humorous I couldn’t resist mentioning it. There’s no shortage, though, of famous and infamous types who’ve attempted to parlay reduced poundage into increased public acceptance. There’s Fergie, the overeating royal who found true happiness in the States shilling for Weight Watchers. There’s Monica Lewinsky. She likewise dropped a few, got work as a weight-loss plan spokesperson, but then, unfortunately, put more than a few back on. That poor girl has never been able to tell what she should and shouldn’t put in her mouth.

There’s Broadway diva Jennifer Holiday, who tipped the scales at 380 pounds when she starred in the hit musical, Dream Girls. As it turned out, there weren’t a lot of parts for nearly-400-pound crooners after that one closed, so she made a bee-line for the O.R. Presto, 280 surgically removed pounds later, she’s a television “heavyweight” with a role on “Ally McBeal.”

There’s Meat Loaf, who figured maybe no one would notice he hasn’t had a hit since the Carter administration if he turned into a slim jim. And, of course, there’s the new and improved Linda Tripp. That didn’t exactly turn out to be money well spent, now did it? The surgeon who makes her over into America’s sweetheart is going to get the Nobel Prize for medicine, believe me. I’m not sure science is quite there yet.

If I’ve forgotten anyone, you can hear all about them on “Entertainment Tonight,” in the show’s ongoing “Where Are They Now?” series, which specializes in celebrity triumphs over tubbiness. It’s such a predominant theme the series really ought to be called “How Much Do They Weigh Now?”

You see my point. The bar is so low you can stub your toe on it. New and ludicrous paths to celebrity are continually becoming accepted within our culture. People achieve notoriety by running around nude on reality shows, taking part in heinous crimes, getting their penises cut off, marrying semi-comatose billionaires or, in the case of Elizabeth Taylor, simply remaining above ground.

Now we’ve added one more to the ridiculous list: losing weight. The time has come, don’t you think, to ask ourselves where all this is headed? What’s next? Worldwide fame for managing to get out of bed in the morning? Public acclaim for not going through the yellow light? Pulitzer Prizes for punctuality? How likely are our children to aim for true greatness tomorrow if we teach them today to place so much value on relatively trivial traits and achievements? The dawn of a new millennium seems as good a time as any to pose that question.

Along with this one: Why hasn’t Al Roker felt the same compulsion to drop poundage felt by almost every other super-sized human in show biz? America’s cuddliest weatherman — an alien life form? Could it be? Do you think?