"Food is fuel."

If you've heard that analogy once, you've probably heard it a hundred times. In fact, over the last couple of years, it's become something of a catchphrase among nutrition and fitness people.

Which is exactly why we need to challenge it.

The way we talk affects the way we think. And when we treat food as "fuel" and our bodies as simple machines, we ignore some fundamental aspects of nutrition, fitness, and health.

In the process, we actually make it tougher to meet our fitness goals. We also rob ourselves of a significant source of meaning, connection, and pleasure. Let's take a closer look.

The Problem with "Calorie Math."

I'll start with the practice of "counting calories."

On the surface, it seems to make sense. Put a certain amount of "gas" in the tank, and the "engine" (you) should run. But don't put in more fuel than the tank needs or it will "overflow." In the form of love handles, or muffin top.

The thing is, if you've spent any time doing "calorie math," you'll know that trying to calculate precise inputs and outputs can be very frustrating in theory (because calorie counts for many food items can be hopelessly wrong ) and in practice.

Perhaps you ate more calories than you thought you should... but got leaner.

Or you ate fewer calories than you thought you should... and gained weight. (Or you didn't lose that last stubborn 10 pounds.)

Or you started eating breakfast instead of skipping it... and dropped a couple of inches off your waistline.

According to the simplistic "food as fuel" view, none of this should be possible. Yet it happens all the time.

Why?

Because Human Bodies Aren't Combustion Engines.

We're complex, dynamic, organic, and infinitely sensitive systems.

More like the complete cast (and director, and producer) of a fantastic movie than a car. Even a fancy car, like a Ferrari.

For example: Research now shows that all food isn't created equal, and what we eat isn't necessarily what we absorb .

Dozens -- maybe even hundreds -- of factors affect how we digest, process, and use the food we eat.

This means that the fuel, or calorie, value of food outside the body isn't necessarily the same as the value inside the body .

(For more on why, see this research review .)

Food Is More Than "Fuel" Or "Energy" Or "Calories".

True, the macronutrients (proteins, carbohydrates, and fats) in food do contain "energy" or "calories." (Or, perhaps most correctly, "chemical bonds that, when broken, are used to create ATP.") And that energy keeps our bodies running.

But when we focus on "energy" and "calories," we're only telling part of the story.

That's because food also includes micronutrients, phytochemicals, zoochemicals, water, and more.

And these substances play a key role in our health and functioning .

Think of these as character actors in a movie. They may not be the big players. They don't really provide "energy" (or fuel) at all.

Yet their dynamic interactions create the spark. They're absolutely critical for performance, mood, and optimal long-term health. In other words, without them, the show won't go on.

Take just three examples:

• build bones,
• clot blood,
• regulate blood pressure,
• keep our muscles and heart pumping, and
• maintain cell communication.

• convert food into energy,
• the nervous system (including the brain) function,
• tissues grow, and
• red blood cell production.

• offer DNA protection against free radicals,
• protect against cancer,
• decrease risk of heart disease, and
• reduce overall mortality.

And that's only a tiny part of the picture! (If you'd like to find out more, check out this review article .)

In the end, when we reduce food to simple fuel, we start negotiating our diets on the basis of their caloric load. A 200 calorie, micronutrient devoid soft drink offers the same amount of fuel as a 200-calorie, micronutrient-rich vegetable dish.

That's when we get into trouble from a health and performance standpoint.

Food Is Smart. And So Is Your Body.

Here's the point: The "food as fuel" story reduces food to gasoline, our bodies to stupid machines, and you to a calorie accountant.

And that's not only dangerous -- from a health perspective -- it's sad. Because you're more than that. Food and your body deserve a lot more recognition and honor.

The more I learn, research, and coach, the more I'm amazed at the power of food. It's packed with meaning, information, communication.

Every food decision we make sends a message to our body.

Every food choice is an opportunity to direct, shape, and remake our health. Our body composition. Our performance. Our well-being.

And that's hardly the same as "filling up the tank."

Food Is Also Shared Humanity. And Connection.

I'm trained as a physiologist and biochemist. So I often look at food through a science lens. But that's not my only perspective. It can't be.

Because I also coach clients, it's essential to recognize that sharing food is a fundamental human act. Breaking bread (or whatever other food is on the table) is part of our history. Our culture. Our legacy as humans.

To think of food as "fuel" completely ignores this. And robs us of a meaningful way to connect with our families, our friends, and our communities.

So, the next time you hear somebody say that "food is fuel," maybe you can stick up for those bit players -- the hardworking phytochemicals, minerals, vitamins. Maybe you can challenge the whole idea of calorie math. Or maybe you can share something delicious.

Because food isn't just fuel.

Sure, in one very limited sense, food does provide us with "fuel." But the analogy is limited.

Worse, to look at food in this overly simplistic way will not only limit your health and fitness, it may also affect the quality of your relationships, and -- ultimately -- the expression of your own humanity.

Want some help finding the best way of eating for you? Download this free guide: Paleo, vegan, intermittent fasting... Here's how to choose the best diet for you .

About the author: John Berardi, Ph.D. is a founder of Precision Nutrition , the world's largest online nutrition coaching company. He also sits on the health and performance advisory boards of Nike, Titleist and Equinox.

Dr. Berardi was recently selected as one of the 20 smartest coaches in the world by livestrong.com, the Internet's most popular fitness site.

In the last five years, Dr. Berardi and his team have personally helped over 30,000 people improve their eating, lose weight, and boost their health through their renowned Precision Nutrition Coaching program.