You can change a habit in 21 days. But it takes thousands of years to change the genome. As it turns out, that basic Biology 101 factoid has an enormous impact on the efficacy of your wellness program.

Not all fitness methods are created equal. Some align with the body’s natural processes, taking advantage of the hormonal, chemical, physical and mental interplay that defines the parameters of existence. Their effects compound across all the body’s processes, to include the whether, when, and how the body binds glycerides together to form triglycerides within fat cells, and whether proteins combine to repair and strengthen muscles or are consumed for energy.

And then, there’s the Nautilus machine.

Let me explain.

The human body was created to endurance hunt, then fell prey through short high-energy bursts of physical activity. Our ancestors could run a gazelle to exhaustion by sheer persistence, and could then win the physical scuffle to turn fauna to food at the end of the chase. All of those activities are what today’s exercise gurus would term “functional fitness” – whole-body involvement at various levels of intensity in a wide variety of time domains.

Those activities produce neuromuscular responses that influence the macro- and micro-hormones that govern all biological processes in the body (google Barry Sears and Greg Glassman for background here). The greater the systemic involvement in movement, and the greater the intensity of that movement, the greater the beneficial adaptation that results. Most importantly, that adaption occurs systemically, not in isolated parts of the body. The bloodstream carries the macro-hormones that govern how the body handles food (whether it stores fat or burns it, and whether it builds muscle or tears it down).

What I’m saying is that the best way to a six-pack isn’t doing crunches. It’s whole-body high-intensity functional movement.

Run. Squat. Jump. Lunge. Do pullups and pushups. Pick up heavy things (safely, of course).

Your exercise regime should strive for the maximum muscle involvement at every turn. Unless you’re a bodybuilder taking steroids, isolation movements are ineffective in the absence of whole-body movements that produce genetically-programmed hormonal and chemical responses with inherently beneficial whole-body effects.

Our ancestors didn’t survive by doing isolation movements. It makes sense that the body doesn’t reward them today, either.

This set of biological certainties is somewhat controversial, largely because of the economic size of the industries designed around various silver bullets – machines, powders, supplements, etc. Put enough marketing power behind it, and you can promulgate any collection of misunderstandings you like (seriously intelligent people used to think the earth was flat). But just because someone discovers a new way to isolate the biceps in an exercise movement doesn’t mean it’s going to have a positive impact on your fitness level.

What’s the upshot of all of this? If you’re going to spend time and money on a wellness and fitness program, it might as well be one that works.

In one of life’s beautiful ironies, the most effective fitness programs I’ve ever encountered are incredibly inexpensive and require very little equipment, overhead, or expense. The best place to start is at www.crossfit.com. Then check out www.mtnathlete.com. The first program is imminently scalable for all levels. The second is not for the faint of heart.

Make no mistake, though. These programs are the most difficult I’ve ever taken part in. That’s why they work as well as they do. Does their degree of required effort mean that many employees will not do them? Absolutely. But their incredible viral growth over the past ten years proves that when you tell people up front that they’re going to work harder than they’ve ever worked, and that maximum effort is the surest, shortest, and most rewarding path to success, you’ll be surprised who joins.

If you’ve been sugarcoating wellness and fitness, it’s probably time for a dose of brutal honesty. Our bodies were designed to respond to the demands we place on them. If our existence is characterized by little movement or exertion, our bodies will reflect that fact. Results demand effort, and effort is the shortcut.

“But what about the employee who can barely get to and from the car?” The most important takeaway is this: intensity is relative. When a deconditioned person exercises at what is a high level of intensity for their current level of physical fitness, their body responds just as favorably as if they were putting in a world-record performance. The formula works across the entire spectrum of fitness levels. It’s all about personal gains, and improving your own personal bests.

The glacial pace of genome adaptation can work for you or against you. If you align your fitness program with the way the body is genetically programmed to respond – whole-body involvement at as high intensity as possible – good things happen in your wellness program.