What can I eat to keep my energy levels up throughout the day?

By eating small, balanced meals or healthy snacks every three to four hours, you provide your body with a near constant supply of energy. It just takes a little bit of planning. Because you won't find yourself terribly hungry, grazing will also keep you from binging.

Prepare meals and snacks in advance. Carrying fresh veggies that need no preparation, such as carrot sticks, snap peas and cucumber slices is a smart way to have a healthy snack on hand that will prevent you from raiding that office vending machine or pulling into the local burger joint. You can also choose to enjoy natural popcorn with no added salt or butter for a high fiber snack that can be quite filling. Remember to buy some artificial butter flakes or powdered Parmesan cheese for health-conscious seasoning. A cup of low fat yogurt with a low fat granola bar or fresh fruit can satisfy the munchies, too, with no guilt.

When your blood sugar level drops, your energy lags. You can keep your blood sugar level up throughout the day by eating three small to medium meals plus two nutritious snacks that include the right nutrients. Click on the video to learn more from Harvard Medical School's Dr. Julie Silver. 

A quick hit of energy from food such as candy bars or other high-calorie, low-nutrition treats won't do the trick when you're trying to beat an afternoon slump. The body responds differently to different types of food, and eating carbs with a high glycemic index, such as sugary drinks or snacks, can lead to energy highs and lows that may exacerbate the post-lunch dip.

However, food can help maintain your energy throughout the day. Although researchers disagree about how much of the post-lunch energy dip is attributable to the noontime meal, overall energy levels and mood can be affected by what you do or don't eat throughout the entire day.

To fuel your brain for every thought and action you perform throughout the day and avoid feeling tired, you need a balance of the three key macronutrients—carbohydrates, protein, and fat—in your diet. A balance of these macronutrients will help:

• Keep blood glucose levels steady; blood glucose (sugar) regulation can enhance cognitive performance.
• Prevent hypoglycemia, a low blood sugar condition that can develop when a person doesn't eat enough or when a person eats excessive refined sugar. While it lasts, hypoglycemia impairs memory, shortens attention span, and causes irritability.
• Maintain the equilibrium of certain amino acid concentrations in the blood, which helps regulate the production of serotonin, a sleep-promoting hormone.

Because different people have different reactions to food, it's difficult to recommend the best macronutrient ratios for sustaining afternoon energy levels. Start with a basic ratio of about 55% of your calories from carbs, 30% from fat, and 15% from protein, and then fine-tune it to your own needs by trying slightly different combinations of each to see what feels best to you.

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