Independent of the underlying causes behind low weight, a very low BMI (such as BMI 18.3) can have serious health consequences.
People that are underweight tend to be very tired and prone to exhaustion. The lack of nutrients can also deplete the immune system, making a person much more susceptible to illnesses and infections. Low iron intake can lead to anemia, as state where less oxygen is carried in the blood, furthering their feelings of exhaustion and reducing organ function.
Without adequate nutrition, your body's immune system may not function properly.
Vitamins A and C are of particular importance to healthy immunity, and being underweight may mean you don't have enough reserves on hand to prevent illnesses from the common cold to cancer. Lowered immunity makes it difficult for your body to fight off viruses and bacteria that contribute to disease and sickness.
Females who don't weigh enough may not menstruate on a regular basis or at all. This might interfere with fertility now and down the road because your body's reproduction isn't regulated normally, which can skew ovulation and make it difficult to sustain a healthy pregnancy.
In order to gain weight, you will have to eat more calories.
The best way to add weight is to increase your intake of complex carbohydrates, particularly whole grain ones. Foods like whole wheat bread, muffins, pasta, crackers, Noodles, and bagels are good to include. Also, legumes and fruits would be wise choices.
You will need to include regular exercise and strength training into your lifestyle in order to prevent gaining too much weight as fat. And, as I mentioned, those extra calories should come mainly from additional carbohydrate.
It is best to gain weight slowly and steadily. This will help to ensure that your weight gain is in the form of lean body mass and not excessive fat.
Tips to gain weight
- Drink 6 glasses of water a day.
- Eat lots of raw fruits and vegetables (green leafy vegetables are great)
- Do not drink coffee, or alcohol.
- Do not eat processed foods (sugar, white flower, ...)
- Keep track of everything you eat.
- Avoid red meat and animal fats.
- Eat frequent but small meals.
- Reduce intake of dairy products.
- Do not smoke.
A qualified nutritionist will try to help you gain weight safely, and once you have reached your goal will help you to ensure you eat the right amount of food to meet your needs but also to be in balance and remain within a healthy weight range.