I recently had a conversation with high-performance nutrition expert Cheryl Zonkowski. She consults with professional athletes, tactical operators, and other people interested in enhancing their cognitive and physical performance through their nutrition. When I asked her what nutrition advice she would give to law enforcement officers, she paused and then said, "Eat real food."

But, of course, that simple advice can become fairly complicated when you try to translate it into real life practice. If you look at popular nutrition literature, you will find there is a seemingly endless number of choices for the "best" foods to eat; the "best" way to prepare foods; the "best" diets for weight loss, improving health, increasing performance, and on and on.

The law enforcement lifestyle complicates this even further. As officers we tend to eat during hours when other people are sleeping, eat on the fly between calls, eat the sugary foods that give a quick burst of energy, eat what is available where we are working, and eat what does not break the bank.

But as WebMD explains in its slide show "Brain Foods That Help You Concentrate," poor eating habits create problems that go well beyond the physical issues involving weight, cholesterol levels, and blood pressure. "If your diet lacks essential nutrients, it can hurt your ability to concentrate. Eating too much or too little can also interfere with your focus," WebMD says.

Since concentration and focus are critical in the law enforcement profession, we really do need to think about our nutrition as a key element of our performance.

What to Eat

Coach Greg Glassman, the founder and CEO of CrossFit ( www.crossfit.com ), personally taught a CrossFit Level 1 seminar to my SWAT team. Speaking about eating for optimal health and performance, Glassman said, "Eat meat and vegetables, nuts and seeds, some fruit, little starch, and no sugar."

Broadly stated, Glassman was telling us how to get our protein, nutrients, essential vitamins and minerals, fiber, and antioxidants. In just 14 words, he outlined a great starting point for developing a nutritional plan for improving health and wellness and enhancing performance.

Glassman further explained that a simple plan exists for shopping for this nutritional approach. He told us to buy only the foods in the perimeter of the grocery store. After taking a moment to visualize where I shop for food, I immediately knew he was right. All of the processed foods are in the center aisles, and the fresh foods are along the perimeter. I have even read that over 60% of the food offered in grocery stores is processed.

When to Eat

In their book, "The Brain Always Wins," Dr. John Sullivan and Chris Parker explain that "30% of your calories are consumed by your brain at rest." Think about that for just a moment — our resting brains are utilizing our nutritional intake to a significant degree, let alone our active brain, our muscles, our organs, and our nervous systems. Looking at it this way, you can see that providing our bodies with a good, clean, consistent source of the nutrition that fuels its needs is imperative for optimal functioning.

When I talk to or read the works of sports scientists and high performance nutritionists, the advice to eat 4 to 6 small meals per day pops up over and over again. This means having something to eat approximately every three hours. Proponents of eating this way say that it increases metabolism, improves energy, assists with concentration, bolsters mood, and helps to keep your blood glucose and insulin levels steady.

How to Eat at Work

As you know, eating on the job has its challenges, especially when you are assigned to late night or morning watch shifts. Preplanning and preparing your meals before your shift and bringing the food to work in a cooler is the ideal way to go. On whatever day precedes your work week, set aside time to prepare a variety of fresh, nutritious foods and pack them into containers that will fit into your work cooler. Some companies sell cooler bags with containers and compartments designed specifically for this purpose.

Greg Amundson, a law enforcement officer and the author of the newly released book "Firebreather Fitness," told me that he packs his cooler with individual containers using a "40% protein, 30% carbohydrate, 30% healthy fat" approach. Amundson said that this simple plan has done wonders for his energy levels, strength, and overall performance.

Discipline yourself to bring your cooler to work every shift and you'll have your food at the ready, which will allow you to eat consistently and healthfully. There will be no need for you to hit the drive-through.

Nobody is Perfect

That said, life happens. Even former Navy SEAL commander and owner of SEALFIT ( www.sealfit.com ), Mark Divine, recognizes that there is a difference between ideal eating and real eating. He utilizes an "80/20 Rule" by eating a Paleo diet 80% of the time and allowing himself to cheat 20% of the time. (Note: The Paleo diet is based on the idea that the human body performs best when we eat the kind of hunter/gatherer diet that fueled our ancestors.)

Photo via Getty Images.

Divine recently discussed the 80/20 Rule in his SEALFIT blog. He wrote: "Being deployed into the field is a big challenge to eating a perfect meal. Even in our busy lives when not 'deployed' to an event or combat zone, shit happens … So I propose this: stick to Paleo when you can, striving for 80% of the week (or year if you deploy frequently). Don't sweat the remaining 20%. With the 80-20 principle, the 20% — MREs and Snickers bars included — is not going to overturn the Paleo fat-burning metabolic diesel engine you've worked hard to create."

Every Body is Different

Not only does real life get in the way of ideal eating, but your individual likes, dislikes, allergies, and tolerances also will dictate what a "Real Food" diet looks like in your work cooler. Maybe you cannot have nuts. Maybe you are like me and you cannot eat some tree fruits. Maybe you are like some of the incredible athletes I have met or read about who are vegetarians or vegans. Maybe eating in the way recommended in this article would require a drastic lifestyle change and you need to transition your diet. No matter what, it is imperative that you understand that nutrition is very personal. A specific diet or way of eating that's optimal for one person may not be ideal for another.

To this end, you should consult with a knowledgeable doctor or professional nutritionist regarding the kinds of foods, the quantities of foods, and the frequency of eating that works best for you. Also, pay attention to how you feel after you eat. Do you feel sluggish or energized? Do you feel uncomfortable or content?

Above all, though, when it comes to eating for performance, it is most helpful to remember the words of Leonardo Da Vinci, who wrote, "Simplicity is the ultimate form of sophistication."

George Ryan is a sergeant with a major Southern California agency. He spent 17 years in SWAT, and he created his department's Peak Performance and Recovery Training program.