However, undernourished people are often thin and short, with very poor energy levels; and swelling in the legs and abdomen is also common. People who are undernourished often get infections and frequently feel cold. Micronutrient malnutrition
Micronutrient malnutrition results from inadequate intake of vitamins and minerals. Worldwide, deficiencies in iodine, Vitamin A, and iron are the most common. Children and pregnant women in low-income countries are at especially high risk for micronutrient deficiencies.Anemia is most commonly caused by iron deficiency, but can also result from other micronutrient deficiencies and diseases. This condition can have major health consequences.It is possible to have overnutrition simultaneously with micronutrient deficiencies; this condition is termed the double burden of malnutrition. Protein-energy malnutrition
Undernutrition sometimes refers specifically to protein–energy malnutrition (PEM). This condition involves both micronutrient deficiencies and an imbalance of protein intake and energy expenditure. It differs from calorie restriction in that calorie restriction may not result in negative health effects. Hypoalimentation (underfeeding) is one cause of undernutrition.Two forms of PEM are kwashiorkor and marasmus; both commonly coexist. Kwashiorkor is primarily caused by inadequate protein intake. Its symptoms include edema, wasting, liver enlargement, hypoalbuminaemia, and steatosis; the condition may also cause depigmentation of skin and hair. The disorder is further identified by a characteristic swelling of the belly, which disguises the patients undernourished condition. Kwashiorkor means displaced child and is derived from the Ga language of coastal Ghana in West Africa.
Usually dogs are known to understand when its time to eat in their bailey chair, and this helps prevent issues. Bailey chairs can be made and are sold. Also, a simple chair turned upside down can be successfully used for this purpose. In two unrelated incidents in Latvia and Australia megaesophagus developed in dogs that had eaten certain brands of dog food, however no agent that could have caused the disorder has been found in lab tests of the food. Diagnosis
An important distinction in recognizing megaesophagus is the difference between when a dog regurgitates or vomits. When a dog regurgitates there is usually not as much effort involved as when a dog vomits. Often when regurgitating, the dog will tip its head down and the liquid and/or food will almost appear to "spill out" of its throat.One of the primary dangers to a dog with megaesophagus is aspiration pneumonia. Because the food stays lodged in the throat, it can often be inhaled into the lungs causing aspiration pneumonia. One way to avoid this is to make sure that every time the dog eats or drinks anything, that the dog sits for at least 10 minutes afterward or is held in a sitting up or begging position. This disorder has a guarded prognosis, however, a successful management technique is vertical feeding in a Bailey Chair. Affected breeds
Cats
Affected breeds:

American Shorthair
Persian (cat)
Siamese (cat)

Horses
Megaesophagus is rare in horses. It is more frequently reported in Friesian horses than in other breeds.