While the rest of the world, including the author of this piece, is trying their best to lose their excess kilos there is a significant number of people, male and female who desperately need to gain weight. A large number of Bangladeshis, and this figure comprises mostly girls, are underweight. And this is a problem, not because of the appearance, but because of the poor health these girls sometimes suffer from. Very poorly nourished people may have a lack of immunity or physical strength. When underweight girls become pregnant, not only do they become even more anaemic and weak, they also give birth to and raise children who may be unhealthier (both in terms of development and overall resistance to illness) than others of their age.
When a very underweight person asks for weight gain advice, we usually brush them off, but thinness can be a problem. This article will give those who want to gain weight a guideline that may help them reach their ideal size. Bear in mind, important causes for low weight or weight loss are different diseases including eating disorders, tuberculosis, cancer and hormonal disorders. If you are underweight because of these reasons, then it may be harder for you to gain weight till you have gotten better.  
Firstly, remember to take it slow. Set realistic goals for yourself. Weight gain is as hard as weight loss and takes almost as long. Do not lose hope. Aim to gradually gain weight over at least 4-6 months.
Secondly and surprisingly, start exercising. Join a gym or pick up a sport. This will increase your appetite. Exercise will help you gain weight by gradually building muscle mass. Also, if you get older, even a skinny person may develop an unsightly belly, which can be avoided by regular exercise throughout life. Combine weight training, cardio and free hand to gain weight. However, make sure you do the exercises under the guideline of an instructor. You do not need to hire a personal trainer but make sure the gym you are going to, if you do decide to go to a gym, has a trained instructor. He/she will be able to give you a guideline which you can follow. It's best to avoid running and stationary biking, these may make you lose weight. No appetite? Walk for 15 minutes before a meal!
A healthy diet will help you more than dietary supplements and medications for weight gain. Remember not to keep eating too much, simply because you can. You may see the weight suddenly piling up when you've crossed your 30s or 40s, and your miraculous metabolism has taken a dip. The trick is to watch what you eat, irrespective of your size and age, so that you look and feel young always.
Eat nutritious food and eat often. Sports nutritionists will encourage budding athletes to eat up to 6 meals a day, (or at least 3) containing all four important nutrients: proteins (meat, fish, eggs, milk and dairy products, beans and soya meat), starches (potatoes, rice, noodles, pasta, bread), fat (oils of all kinds, butter, cream, ghee) and vegetables.
Vegetables aren't only for weight losers, it's essential for gainers too. A good amount of fibre will prevent constipation and increase appetite. Choose sweet or starchy vegetables and fruits instead of watery ones. Examples are bananas, mangoes, jackfruit, dates, carrots, sweet corn. Eat nuts because they contain healthy oils and antioxidants. Try having dry fruits too.
Add a few teaspoons of honey to your drinks instead of sugar. It will be processed by your body more easily. Other easy ways to add calories to your food is by drinking a glass of full cream milk every morning (or soya milk for those who are lactose intolerant), adding a cup of yoghurt or a handful of nuts to your salads, adding peanut butter to your bread and cheese with your omelette, or two teaspoons of extra olive oil in your cooking. The trick is in moderation. Don't overdo it as thin people often get sick if they overeat and that would reverse the entire process.
If you want to gain weight you will have to increase your caloric intake, i.e. the amount of food you take to provide energy. If you need about 2000 calories for your day-to-day activities (your calorie needs will depend upon your age, size and amount of activity) then you need to eat food that contains more calories than that. Aim to slowly increase your caloric intake, from 200 extra calories a day up to 500 extra calories. A visit to a trained nutritionist may help. Weigh yourself around the same time everyday.   
If you are trying to gain weight after illness, then the diet needs to be a combination of proteins (at least 5 ounces of meats and fish with a glass or two of milk), vitamins, minerals and carbohydrates. This is important to recover the nutrients you had not taken because many people tend to eat poorly when they are sick. This will also provide the necessary fuel for healing the cells that may have been damaged during illness. Make milkshakes or smoothies with fruit to ensure you get the nutrition you need. Have thick creamy soups and not the watery ones. It's best to avoid spices till you feel a little better.
For weight gain and loss, restraint is equally important. As people who are underweight often suffer from lactose intolerance or IBS (Irritable Bowel Syndrome) it may be harder for them to enjoy calorie rich foods.
Don't stress yourself beyond your comfort zone. With healthy eating (300 - 500 extra calories) and moderate exercise, you will surely be able to gain at least a pound a week.

Dr. Naomi Mirza
Medical Consultant at Maya.com.bd