Rarely.

However, it is an issue that's more common than you might think.

An 'ectomorphic' body type is someone who is (generally) tall, slender, with long fingers and thin wrists. Such an individual has a tough time gaining weight, since his / her body tends to burn energy at a rapid rate. A 'high metabolism' is common, and these (lucky) individuals can literally eat all they want without gaining an ounce. This can be partly attributed to genetics. Many non-nutritional factors can also contribute to low body weight, such as stress or nervous tension. Some experts believe that emotional stability is an important factor in weight gain, since this may allow the body to retain calories better.

Being too skinny is not a good thing. Risks include slow recovery after illnesses and reduced immunity. Being underweight can also mean low endurance, strength and in some cases lower self esteem.

Diet plays the most important role for a 'hard gainer'. The energy density of foods is important factor to gain weight. Energy density refers to the amount of energy or calories compared to the weight of the food. For example, a macaroni and cheese is more energy dense than a corresponding amount of white rice and potatoes.

Here are some effective tips for those looking to gain weight.

Nutrition tips.

Eat more good-quality food.

To gain weight, eat food with extremely high caloric value. Try to increase your food intake without consuming too much fat and sugar. In other words, eat more protein, complex carbohydrates and foods rich in vitamins and minerals. Fast food is not the solution!

Eat regularly.

Regular meals, especially breakfast, are important if you find it difficult to gain weight. Taking your time with meals and making sure you are relaxed is also important to ensure that your digestive system functions properly. Do not eat in a hurry or under stress. Enjoy food, chew it slowly and do not be distracted while eating. Eat at fixed times.

Eat more often.

Eat five or more meals a day. Drink plenty of fluids that supply calories like juices, protein shakes, and sports beverages. Eat starchy grains and vegetables, such as rice, oats, pasta and potatoes. Add yoghurt, sour cream, sauces and dressings to plain foods and salads. Eat bread with fatty spreads such as avocado, peanut butter and olive or canola oil margarines. Try to eat more 'good fats' from nuts / olive oil as opposed to saturated fat from butter. Dry fruits are a great source of energy. Small size cashew nuts, almond and raisins have bundle of energy. From the milk Group, consume more milk, cheese, yogurt, cottage cheese, ice cream. From the grain group, consume more cereals, breads, rolls, pasta, muffins, pancakes, rice.

Eat more protein.

Protein is essential to the body, for repair, to enable the immune system to function and for recovery from illness. If you are recovering from illness, it is important to include adequate protein in your diet. Good vegetarian sources of protein include: cereals, nuts & seeds, Soya products (Soya milk, tofu etc) and pulses. Milk, yoghurt, cheese, and eggs are also excellent protein sources. Try to include a protein source at each meal.

Avoid caffeine and nicotine.

Caffeine and nicotine are stimulants that increase metabolism. Try to minimize them, since this helps your body to retain maximum nutritional value from what you eat.

Eat late at night.

Having snacks at bedtime may help to gain weight, as long as it does not interfere with sleep. This allows your body to 'retain' those calories rather than burning them away.

Exercise - more weight training, less aerobic exercise.

Lifting weights, under supervision, is an excellent way to gain muscle mass without burning excess calories. Cut down on cardiovascular (aerobic) exercise and focus on high intensity weight training. Ideally 2-3 sets of 6-8 repetitions results in hypertrophy (increased muscle mass).

The importance of sleep.

Sleep is perhaps the most important component of weight gain. 6-8 hours of sleep is important everyday to gain weight and improve fitness. Less sleep will result in fatigue, and muscle wastage. During sleep, the body recuperates and regenerates. This means that all the food eaten during the day is assimilated and then distributed amongst the various tissues of the body. New cells are generated, and old cells are destroyed. When the body has the right combination of high intensity exercise, good nutrition and sufficient water intake, the muscles become fuller, larger and more well-defined. This is the dream of anyone looking to gain weight.

In summary, good nutrition, rest, relaxation and regular exercise help in increasing body mass. Good luck!