Suffering from cravings, constant hunger, depression or fatigue? What's really eating you could be poor nutrition.

Problem #1: Low energy/fatigue

Cause: A low-carbohydrate weight-loss diet could be the culprit. Skimping on carbs, the body's prime source of immediate fuel, may leave you physically tired and mentally sluggish. Other possibilities: not getting enough iron or water.

Solution: Eat plenty of complex carbs to stay energized and mentally sharp while still losing weight. Add iron-rich foods such as oatmeal and spinach, and drink at least eight glasses of water daily.

Best foods to eat: Chicken and vegetable stir-fry over brown rice; chili with beans; black-bean-and-Wehani-rice salad; whole-grain cereal with fresh berries; brown rice pilaf with pine nuts; whole-wheat noodles with Asian sauces; extra-lean red meat.

Problem #2: Feeling down/depressed

Cause: Not getting enough omega-3 fats from fish or enough B vitamins, especially folic acid, vitamin B6 and vitamin B12, could make you feel down in the dumps.

Solution: Eat two to three weekly servings of fish to get your omega-3s and vitamin B12; two dark-green leafies or legumes a day for folic acid, and several foods rich in vitamin B6 like bananas, whole grains, asparagus and legumes.

Best foods to eat: Seafood chowder with whole-wheat crackers; whole-wheat pita with smoked salmon, cranberry or honey mustard, fresh spinach and pineapple; vegetarian chili; black bean soup; lentil salad; grilled trout fillets; Cajun chicken wrap with cucumbers and tomatoes; peanut-butter-and-sliced-banana sandwich on whole-wheat bread.

Problem #3: Premenstrual syndrome (PMS)

Cause: Consuming too little calcium and magnesium or too much sugar can exacerbate PMS symptoms like moodiness, anxiety, crying spells, bloating, headaches and cravings. Also, eating too few calories may contribute to moodiness.

Solution: Cut back on sweets. Consume more calcium-rich foods like nonfat milk, yogurt and calcium-fortified soy products. Eat more foods high in magnesium, including whole-grains, nuts and legumes, and eat sufficient calories.

Best foods to eat: Baked corn chips with salsa and bean dip; nonfat cottage cheese with pineapple chunks and toasted almonds; black bean soup with a piece of cornbread; nonfat yogurt sprinkled with lowfat granola; nonfat plain yogurt mixed with apricots and apricot jam; oatmeal cooked in nonfat milk and topped with walnuts; calcium-fortified chocolate soy milk.

Problem #4: Constant hunger

Cause: Skipping breakfast or other meals; following a fad diet with too few calories, carbs and/or protein; or skimping on fiber-rich foods. Or, you could be eating too many empty calories -- high-sugar/high-fat processed food that fills you out but not up.

Solution: Spread your food intake evenly throughout the day, starting with breakfast. Combine a little protein and high fiber (which together balance blood sugar and keep you full) with quality carbs at each meal and snack. Stay full on fewer calories by eating lots of fiber- and water-packed foods like vegetables, fruit, broth-based soups and stews.

Best foods to eat: Whole-grain cereal with nonfat milk and fruit; turkey-breast sandwich on whole-wheat bread with country-style mustard; whole-wheat pita stuffed with hummus and roasted red peppers; tossed vegetable salad with broccoli, peppers and kidney beans; a bowl of gazpacho with whole-grain crackers and peanut butter; lowfat, low-sodium vegetable and bean soup and stews.

Problem #5: Bingeing and craving

Cause: Overly strict, prohibitive diets, skipping meals and snacking on sweet and/or fatty snacks. Drinking too many caffeinated or alcoholic beverages also may aggravate food cravings.

Solution: Eat a balanced diet. Curb your sweet tooth with naturally sweet snacks like fresh fruit. To avoid feeling deprived, enjoy small portions of favorite treats a few times a week. Don't drink more than three cups of coffee or one alcoholic beverage a day.

Best foods to eat: Dried cranberries, almonds and fresh berries stirred into nonfat yogurt; sliced mango and papaya drizzled with fresh lime juice; prunes stuffed with almonds; strawberries or dried apricot halves dipped in fat-free chocolate syrup; fruit yogurt sprinkled with chopped kiwi; fruit spritzer (equal parts seltzer water and fruit juice with a twist of lemon or lime).

Problem #6: Irritability, anxiety

Cause: Skipping meals, not eating enough calories or relying on caffeine to give you an energy boost. Overloading on caffeine also can give you the jitters, so limit your consumption to 200 milligrams or less daily.

Solution: Consume at least 1,800-2,000 calories a day, focusing on high-quality foods, to keep your energy and metabolism in high gear. If you can't maintain your weight on a healthy number of calories, try upping your exercise rather than cutting calories. Boost your energy with natural foods rather than relying on stimulants like caffeine. Limit coffee, tea and colas to 2 cups (or 200 milligrams) daily. A 5-ounce cup of coffee supplies 60-180 mg of caffeine, depending on strength and blend; an 8-ounce latte, 50-70 mg; a 2-ounce shot of espresso, 51-130 mg; a 5-ounce cup of brewed tea, 38-77 mg. Avoid leaded java after 3 p.m.: Caffeine can linger in your body for up to 15 hours and interfere with a good night's sleep.

Best foods to eat: Whole-grain cereal with nonfat soy milk and sesame seeds; whole-grain pancakes with nonfat fruit yogurt and wheat germ; oat bagel topped with soy butter and pineapple chunks; fresh fruit parfait layered with nonfat yogurt; roasted vegetable shish kebab; broiled salmon with lemon juice; roasted chicken with quinoa; lean hamburger (7 percent fat) or soy burger on a whole-grain bun stuffed with lettuce, roasted onions and peppers; decaffeinated coffee and herbal teas.

Problem #7: Mental fogginess

Cause: Skipping breakfast or not getting enough antioxidants (found in produce) and vitamin E (found in nuts, seeds and wheat germ) may leave you feeling mentally dull, or even contribute to impaired memory. Or your lack of focus may be due to an insufficient amount of iron in your diet, finds a Pennsylvania State University study.

Solution: Rise and shine with a healthy breakfast to prevent fading by lunchtime. Load up on foods rich in antioxidants, including fruits (especially cherries, red grapes, dried plums, raisins, berries, fresh plums and oranges) and vegetables (especially kale, spinach, Brussels sprouts, beets and red bell peppers). Consider taking a multivitamin, plus a mineral supplement that contains vitamin E. And be sure to get the recommended 18 milligrams of iron a day.

Best foods to eat: Whole-grain waffles with frozen blueberries and maple syrup; hot whole-wheat cereal with wheat germ and raspberries; frozen grapes dusted with powdered sugar; equal parts toasted wheat germ, honey and peanut butter spread on whole-wheat toast; tossed green salad with roasted beets and/or pitted cherries; steamed chopped kale or turnips whipped into mashed "potatoes." For iron, go with foods like lean meat, poultry, and seafood.