Caffeine and sugar do provide an immediate energy, but the effect is fleeting. You'll get a longer-lasting effect by substituting high-carbohydrate foods such as fruit, vegetables, juices, or energy bars.

Improve your eating habits in general:

• A carbohydrate-rich diet, including breads, cereals, rice, beans, pastas, fruit, juices, and vegetables, will boost your energy.
• Your three daily meals should represent 85% of your caloric intake. Make up the balance with high-carbohydrate snacks, such as apples or bagels.
• Protein quickens thinking and reactions. Choose lean sources, such as skinless chicken, fish, and nonfat yogurt, because digesting fat diverts blood from the brain causing weariness.
• Vitamin deficiencies sap energy -- take a supplement daily.

Dehydration causes lethargy. Drink six-eight glasses of water daily -- more if you're physically active or dieting.

Regular exercise increases circulation, blood sugar levels, metabolism, and helps maintain your ideal weight. A 30-minute daily walk is all it takes to release adrenaline and mood-elevating endorphins, increasing alertness. For a quick exercise boost, dash up and down a flight of stairs.

Power napping improves concentration, mood, and job performance. Putting your head down on your desk, for 15-20 minutes, contradicts our natural, mid-afternoon energy dip. Nap between1-4 p.m. so that your nighttime sleep isn't compromised.

Avoid alcohol, which saps energy and interferes with nighttime sleep.

If you average less than eight hours of sleep nightly, you're probably suffering from sleep deprivation -- a major cause of low energy levels. Catch-up on lost sleep by retiring early once a week for a full night of intense "recovery" sleep or sleeping late one weekend morning.