Overview
Malnutrition from undernutrition happens when the body does not get enough energy, protein, or nutrients to function and stay healthy. It can affect anyone but is common in older adults, people with chronic illness, and those recovering from surgery or serious infection. It weakens the body, slows healing, and increases the risk of infections and falls.
Symptoms
- Unintentional weight loss
- Loss of muscle and strength
- Clothes, rings, or dentures becoming loose
- Constant tiredness and weakness
- Frequent infections or slow wound healing
- Low mood or poor concentration
- Reduced appetite
Causes & risk factors
- Eating too little due to illness, low appetite, or limited access to food
- Conditions that increase nutrient needs, such as cancer or recovery from surgery
- Digestive diseases that reduce nutrient absorption
- Swallowing difficulties
- Mental health conditions such as depression
- Social factors including isolation or poverty
- Older age with reduced appetite
Treatment & self-care
Care begins with identifying why intake or absorption is low. It generally involves a nutrition plan to rebuild energy and protein intake, treating the underlying illness, and sometimes supplements or specialised feeding under supervision. A licensed clinician or dietitian should assess severity and guide safe refeeding, as rapid changes can be harmful.
See a doctor urgently if
- You or someone you care for is losing weight without trying
- Appetite has dropped for more than a couple of weeks
- Wounds heal slowly or infections keep returning
- An older adult is becoming frail or falling
- Swallowing has become difficult