A weight below normal compared to the height. However, the body structure has to be considered. Many elderly and some young people suffer from undernourishment or malnutrition making them too thin. Stress and emotional problems may also reduce appetite.

You can have a hereditary disposition to being thin. An insufficient diet, both regarding the amount and the content of it can be contributory and hard competitive sports like triathlon suppress the production of sex hormones and thereby making it impossible to gain weight.

Stress and emotional problems might reduce the appetite and cause weight loss, but this is most often seen in young girls in the form of anorexia. These girls often have a mixed-up self-image and think that they are overweight.

Smokers have a larger fat metabolism than non-smokers often leading to an increase in weight in the time after having stopped smoking; so quitting the cigarettes will be the first step for smokers who would like to gain weight.

Children and underweight
No child, regardless of age, needs large amounts of sugar, but small children need a fat – rich diet.  Growing children need more food per kilo bodyweight than adults.  Fruit, vegetables, and fiber are filling and children who eat only these foods risk being full before achieving their caloric requirement.


General advice on disease prevention and a healthy lifestyle can be found in the library article "General Advice - both for the healthy and the sick"

You can gain weight without eating unhealthy food.  People who want to lose weight by keeping their metabolism high should eat three main meals and possibly three snacks daily.  Underweight people can achieve weight gain by eating only two large meals daily.  By skipping a meal the body will normally reduce its metabolism.

The greatest weight gain is normally achieved by skipping breakfast and only having lunch and dinner.

Exercise is still recommended, but preferably before meals.  The metabolism is reduced by exercising on an empty stomach so that fewer calories are burned.

To stimulate the appetite, it is important not to drink too much coffee and not to eat too much sugar in the form of sweets. They both have a filling effect and stop the appetite too soon and then you might not get enough of the healthy and energy rich food. Too much fibre in the food also will suppress the appetite whereas too little will be able to create problems with the stomach.

Do not eat alone.  Appetite is often improved by eating with others.

The way you eat rather than the amount can be the deciding factor to whether you gain or lose weight. 

Herbs that stimulate appetite:

  • Artichoke, Cynara scolymus (leaves)
  • Chili, Capsicum frutescens
  • Gentian, Gentiana lutea (root)
  • Turmeric, Curcuma longa (root)
  • Cumin, Carum carvi (oil)

If none of this has enough of an effect you have to work on your own image. Place yourself in front of a mirror every day, for example, and tell yourself that this is how you look and that your are good enough just the way you are.


Also see "Anorexia", "Appetite, loss of", "Bulimia", and "Stress".