ne of the most common complaints I hear from customers is of fatigue. When I begin inquiring about the possible causes of their tiredness, my first question is whether they eat breakfast, lunch, and dinner. The answer is almost always "no." Bingo! I've already hit on a major culprit of energy deficiency.

Aside from being a highly skilled nutrition detective, I also know that there is a direct link between food and energy. You see, calories are actually a unit of measure of energy, much like watts describe the power output of a light bulb. Foods that contain calories offer energy to your body. When you don't eat, overeat, or choose the wrong foods, your energy may suffer.

Our energy levels are bound to be different throughout our lifecycles, with stress and milestone events affecting our sleep and requiring more mental and physical energy. On a daily basis, however, we should be able to function at the highest level possible. If you feel like something is dragging you down or preventing you from feeling your best, now may be a good time to examine some of your lifestyle practices for clues about any energy exterminators.

Lifestyle Factor #1: Sleep
This one is the most obvious factor that contributes to fatigue. If you don't get enough sleep, you feel tired. Only about 30% of American adults get the recommended eight hours of sleep a night and another 30% get fewer than seven hours of sleep on weeknights. Even if you get enough hours of sleep, the quality of your slumber might not be great. Sleep apnea, which affects millions of Americans, can disturb sleep by repeatedly cutting off air flow during the night. Obesity, which is a risk factor for sleep apnea, has also been shown to cause sleep disturbances at night and drowsiness during the day. Try to practice healthy sleep habits by: going to bed and waking up at the same time every night, aiming for seven to eight hours of sleep a night, implementing a bedtime routine (like taking a bath), and not eating, working, or watching TV in bed. If you have an overactive brain that prevents you from falling asleep, try relaxation techniques such as meditation and breath work for a few minutes before going to bed.

Lifestyle Factor #2: Eating Regular Meals
Like I said before, food gives us energy. Skipping your morning meal after an overnight fast can send your body into starvation mode, in which your brain, blood sugar, and body cannot function optimally and your mood and energy levels dip. Controlling your blood sugar is an important factor in keeping your energy levels up. If your blood sugar gets too low, like if you skip a meal, you have an energy slump until you eat and bring your blood sugar back up. When you do finally eat, if you choose the wrong foods or eat too many carbohydrates (think of how you feel after Thanksgiving dinner), you may tip off a vicious cycle in which your blood sugar and energy levels spike and dip like a see-saw all day long. However, if you eat balanced meals of reasonable size, your blood sugar does not rise and fall in large swings. Instead, you will have a steady release of blood sugar that allows for sustained energy over several hours that helps carry you through to your next meal. Read on to learn more about creating balance in your meals.

Lifestyle Factor #3: Choosing Good Carbs
Without its preferred "fuel" or the right balance of foods, your brain doesn't readily make the chemicals that increase alertness and energy. Carbohydrates are your body's favored source of energy, but the type and amount of energy you get depends on the kind of carbohydrate you choose. Highly refined carbohydrates like a bagel, cream of wheat, or cold cereal with less than five grams of fiber, as well as sugary foods like breakfast bars, muffins, and doughnuts, cause a quick burst of energy (a blood sugar spike) and then a rapid decline in energy (a blood sugar dip) about an hour later. Whole grains are complex, high-fiber carbohydrates that help keep blood sugar at even levels for several hours. Construct balanced meals and snacks that include one or two servings of whole-grain carbohydrate, some protein, and a little fat. See my Balanced Snacks box for some creative ideas.

Lifestyle Factor #4: Caffeine
Caffeine, obviously useful for helping you wake up, may also be keeping you awake, since it stays in your system for several hours. Initially, you may feel more alert and focused, but soon after you'll hit bottom, possibly with a headache or heart palpitations and almost certainly with drowsiness and irritability. Can't live without your morning coffee? One or two cups of coffee, tea, or soft drinks a day is considered acceptable, but try to have them with a balanced meal or soon after, and cut off the caffeine by 1pm. Since you can build up a tolerance to caffeine, take breaks over the weekends so it takes less joe to get you going on Monday morning; you'll sleep better, too.

Lifestyle factor #5: Water
Water is essential for the body to function properly-after all, water makes up about 60% of our total body weight. Even slight dehydration can drain your energy and decrease mental clarity. Be proactive to prevent dehydration and the fatigue associated with it; sip water throughout the day or create a drinking schedule for yourself-don't wait to drink until you are thirsty! Your water needs vary depending on diet, weather conditions, and activity level. Increase your water intake on hot days or if you exercise. For the average person, a good range to shoot for is eight to 12 eight-ounce glasses per day.

Lifestyle factor #6: Exercise
It sounds counterintuitive that you have to expend energy in order to make more, but it's true. Exercise is a terrific energy enhancer. It helps get your blood flowing, provides an outlet for stress and other emotions that build up over time, and it helps you sleep more soundly. Regular exercise can improve your stamina for daily activities and promote mental clarity. Talk to your doctor before you begin an exercise routine and then aim for at least 30 minutes of cardiovascular exercise each day.

Lifestyle factor #7: Nutrient Deficiencies
Wander down any vitamin and supplement aisle and you'll see dietary supplements that claim to boost energy. We now understand that our energy comes from calories and adequate sleep, not from pills (or legal ones, at least). However, there are a couple of situations in which a nutrient deficiency could be causing your low energy. Fatigue and weakness are sometimes symptoms of iron-deficiency anemia. New research on magnesium found that low levels of the mineral make the body work harder and increase energy and oxygen requirements. Legumes, whole grains, leafy green vegetables, and seafood are all good dietary sources of these nutrients. If you suspect you may be low in either one, talk to your doctor first-never self-medicate.

I hope you're still awake and that you have discovered some clues about why your get-up-and-go has got-up-and-gone. If there is more than one lifestyle factor affecting your energy level, choose one to work on improving for now. Hopefully, making that one change will give you the vigor and motivation to make more vitalizing adjustments to your lifestyle.

Balanced Snacks

• Kashi TLC 7-grain crackers with low-fat cottage cheese
• Milton's healthy whole-grain bread with some nut butter
• Eggs with a corn tortilla
• Kashi Go Lean Crunch! cereal with nonfat milk or soy milk
• A handful of raw or dry-roasted nuts with a yogurt or a piece of fruit
• A vegetable salad with soybeans or other beans