Do you experience puffy eyes, swelling feet and hands, dry and scaly skin, hair that's unexpectedly losing its color, slow-healing wounds, achy bones and joints or nails that are brittle or curved? If so, you might be suffering from poor nutrition or malnutrition.This means your body isn't getting enough of the protein, carbohydrates, fat, vitamins, minerals or other nutrients it needs. "The New York Times" "Health Guide notes that eating too little, indigestion, problems with the way your body absorbs nutrients and imbalanced eating are possible causes of malnutrition.AnemiaThe United States National Library of Medicine and National Institutes of Health MedlinePlus website explains that if you have anemia, you lack a healthy number of red blood cells or your red blood cells don't contain enough hemoglobin.Hemoglobin is the substance that makes red blood cells look red. It also enables red blood cells to carry oxygen from your lungs throughout your body. Anemia usually results from iron deficiency. If you're anemic, you can feel easily tired, cold and short of breath, and your heart may race.Fatigue, Dizziness, TinglingLab Tests Online lists fatigue and dizziness, which can occur after skipping just one or a few meals, as signs of malnutrition. These symptoms generally disappear once you start eating balanced meals that include a healthy amount of calories, a form of energy.Vitamin B12, also known as folate or folic acid, plays a big role in red blood cell and nerve function. Insufficient amounts of B12 in your body can lead to nerve damage which in turn can make your hands and feet tingle.Weight LossObviously, weight loss can stem from eating less food than you were eating. But if you're slimming down so much or so quickly that it seems abnormal, seek medical advice to make sure your loss isn't caused by a health problem. If you purposely starve yourself, or you overeat then make yourself vomit, get help from medical and mental health professionals. These habits are respectively known as the eating disorders anorexia nervosa and bulimia.The U.S. Department of Health and Human Services National Mental Health Information Center warns that, if left untreated, eating disorders can cause malnutrition and death. Decreased Mental Function, Development and ImmunityFeeling foggy, confused and cranky can be symptoms of a poorly fed brain. In children, ongoing malnutrition can cause mental and physical developmental delays. Malnutrition lowers immunity, making it easier to get sick and stay sick.Even a plus-sized person can be malnourished if she mostly eats nutrient-poor foods. To prevent malnutrition, make the healthy carbohydrates found in vegetables and fruits the main part of your daily diet, eat less of the unhealthy carbs in sweets, baked goods, chips, and non-whole grains and avoid high-cholesterol protein sources. Instead, get your protein from beans, nuts, fish and lean poultry and meat.