Want to develop a first-rate body? That’s great, but along with that I’d argue that you also need to develop something else.

First-rate intelligence.

First-rate intelligence, according to that great American novelist F. Scott Fitzgerald is “the ability to hold two opposed ideas in the mind at the same time and still retain the ability to function.”

Isn’t that what this column often challenges you to do? To consider conflicting health and fitness concepts concurrently to decide a course of action that’s best for you?

And while I’d love for it to be otherwise and for me to have the ability to simply prescribe a set course of action for you, that cannot be — primarily because the science of human performance is still clearly in a stage of infancy. If you refuse to admit that when you begin to build that first-rate body, you’ll thrash about in an ocean of endless ideas like a non-swimmer shoved off the deck of a cruise ship.

So allow me to offer some words on how to keep your head above the waves while it develops into something first-rate.

When I first started teaching a health-and-fitness course to teachers titled “Simple Ways to Be Well” in the mid-80s, grocery store shelves were filled with fat-free versions of anything and everything.

Kraft and its competitors offered fat-free cheese slices. Wishbone and other condiment producers created fat-free salad dressings. Eventually, Lay’s and its competitors (with the help of science gone mad) produced fat-free potato chips (and, I might add, a great deal of gastric distress).

Even Entenmann’s, my favorite childhood baked goods producer — whose Cheery Cheese Danish Rolls I would eat all at once if mom wouldn’t keep a close watch — offered an entire line of fat-free danishes and donuts.

That’s because avoiding dietary fat had become the thing to do and seemingly for good reason: research showed that it was far easier for the body to store excess dietary fat as body fat than an excess of complex carbohydrates or protein. This discovery combined with the well-established knowledge that complex carbs provide the body its best fuel led to several versions of the high-carb, low-fat diet seeing long stretches atop the New York Times Bestseller book list.

And then the ultimate irony occurred.

People got fat. In record numbers.

Yes, that’s right. During what now might be called the “fat-free craze,” more people got fat than at any other time in history.

How could that be? Because these people couldn’t hold two opposed ideas in their minds at the same time: that both carbs and fat could be both good and bad.

Now its old hat that not all carbs are equal, and that the worst of them, highly processed, simple carbs, become body fat even faster than dietary fat because they create a spike of insulin. It’s even older hat that trans fats and saturated fats increase the incidence of cardiovascular disease, that monounsaturated fats decrease the incidence of cardiovascular disease, and that polyunsaturated fats fall somewhere in between.

So let’s pick another weight-loss strategy that only appears to come from that same old hat: eating less to weigh less. The idea: Consume 2,000 calories per day when your body’s accustomed to 2,500, and since 3,500 calories equals a pound, you should lose one pound per week.

It makes sense, don’t you think? And it does. Mathematically.

But there are opposed ideas at work here, and one is known as the hypo-caloric state. In short, if you shortchange your body the calories it needs, it interprets that deficit as famine and hoards body fat by decreasing its resting metabolic rate.

In that state, the reduction of 500 calories creates no weight loss, but it does make you tired and lethargic.

Exist in the hypo-caloric state for too long, and your body makes another adjustment to save itself from what it fears to be famine that just about insures you’ll gain weight later on. It starts catabolizing its own muscle for energy.

While that immediately increases energy, it also immediately decreases the total number of calories you need because that pound or two of muscle that’s gone used to require up to 150 calories per day.

So once you lose the weight you want, and consume the number of calories you did before the diet, that’s now an excess.

Eventually you become heavier than before, and your body composition takes a turn for the worse. Losing five pounds of muscle and gaining 10 pounds of fat tends to do this.

So as counterintuitive as it may seem, there are times when you may increase the amount of calories you consume because your long-term goal is to lose weight.

It’s an idea that some people will never be able to wrap their head around, but you should be able to — if you work on developing a first-rate intelligence along with that first-rate body.