While most Americans struggle to lose weight, there are some who are underweight and unable to gain enough weight to stay in the healthy range.
While certain individuals may inherently have a high metabolism, others may have an illness or chronic condition that prevents them from maintaining a healthy weight.
Cancer treatments, for example, may cause nausea and food aversions.
People with gastrointestinal or liver problems may be unable to absorb nutrients adequately even if they are consuming what would normally be a sufficient amount for a healthy individual.
Mental well-being is an important aspect of weight maintenance as well.
People who suffer from depression, stress, or anxiety may have loss of appetite and subsequent weight loss.
Being underweight is associated with medical problems including osteoporosis, low muscle mass, weak immune systems, poor wound healing, and infertility.
Children who are underweight may have stunted growth and poor brain development.
In adults, underweight is defined as having a body mass index (BMI) less than 18.5.
In children, underweight is defined as having a BMI less than the 5th percentile for age and gender because the healthy range of BMI varies with gender and changes over time as children get older.
If you or someone you know is trying to gain weight, it does not mean that junk food or fast food meals are acceptable.
The goal is to increase caloric intake, but these calories should still be accompanied by nutrition.
The following suggestions are some simple ways to add tasty, healthy calories to the diet.
Sometimes the thought of having to eat more at any one meal can appear to be a daunting task, especially if nausea or reflux symptoms are a problem.
Rather than focusing on bigger meals at breakfast, lunch, and dinner, try having regular meals at those times but add three snacks throughout the course of the day.
Drinking calories is just as good as eating calories.
Be wary of soft drinks and juice, though, since these beverages often just add sugar to the diet.
Juice should be limited to no more than one glass per day if at all.
Substituting a glass of water with a glass of milk will provide more calories, protein, and calcium.
Make high protein smoothies by adding yogurt or soft tofu to milk and fresh or frozen fruit.
You can add other things like wheat germ or dry milk powder to increase the nutritional content even more.
You can also try drinking beverages after eating so that you do not fill up on fluid before finishing your meal or snack.
Sufficient amounts of protein are important for building muscle mass.
Healthy snacks with nuts or dairy products like cheese and yogurt are easy ways to increase protein.
Fruits can be dipped in yogurt, and crackers or vegetables can be paired with peanut butter, hummus, or bean dip.
Beans and legumes, eggs, or lean cuts of meat, fish, and poultry are also key ingredients for adding protein at mealtime.
Hard-boiled eggs can be a quick and easy snack or an addition to a salad.
Fats are nature's way of packaging a large amount of calories into a small space.
While butter, cream, and other animal-based fats will add calories, fats from plant-based sources like nuts or fruits and vegetables like olive oil or avocado are healthier for your heart.
Try adding an extra spoon or two of olive oil to your serving of soups, pastas, or other cooked foods.
Sprinkle nuts or seeds like sunflower or pumpkin on salads or soup.
Avocado slices go well on salads or in sandwiches.
In addition to trying these suggestions, it may be helpful to meet with a nutritionist who can tailor a diet for you.
You may also need to discuss with your healthcare provider whether you should take any nutritional supplements which are commercially available.