How to tell someone is malnourished? The signs to look for

October 19, 2025 •

5 min read

Malnutrition is a common and serious health issue, with a 2021 review finding that it's associated with a higher mortality rate and longer hospital stays. Yet, it can be a silent condition, making it critical to know how to tell someone is malnourished by observing both subtle and obvious warning signs.

Quick Summary

Malnutrition can manifest through unintentional weight loss, loss of appetite, and changes in behavior, though symptoms vary between adults and children. It can stem from under- or overnutrition and result from various health conditions, social factors, or lifestyle issues. Early detection is vital for effective treatment and better health outcomes.

Key Points

Weight Changes Are Key: Unintentional weight loss of 5–10% or more over 3–6 months is a major sign of malnutrition, even if a person appears to be at a healthy weight.
Look for Physical Cues: Dry skin, thinning hair, brittle nails, and slow wound healing can all be physical indicators of nutrient deficiencies.
Recognize Behavioral Shifts: Emotional changes like apathy, irritability, depression, and poor concentration can signal underlying malnutrition.
Spotting Signs in Children: In children, malnutrition may present as faltering growth, low energy, and developmental delays, requiring different assessment tools like MUAC bands.
Remember It Isn't Just Undernutrition: Malnutrition includes both undernutrition and overnutrition, with overweight individuals also potentially lacking essential vitamins and minerals.
Take Action by Seeking Help: If you suspect someone is malnourished, encourage them to see a doctor for a proper diagnosis and treatment plan to prevent serious complications.
Consider Underlying Causes: Malnutrition can result from health conditions, mental health issues, social isolation, and financial difficulties, so a holistic view is necessary.

Understanding the Complexities of Malnutrition

Malnutrition is not solely a problem of starvation but refers to any imbalance in a person's nutrient intake. This can mean undernutrition, where a person lacks sufficient calories, protein, or micronutrients like vitamins and minerals, or it can mean overnutrition, characterized by an excess intake of calories. Both forms can severely impact health, yet undernutrition often goes unnoticed until symptoms become severe. Recognizing the signs requires a close look at a person's physical appearance, emotional state, and behavior.

Physical Indicators in Adults

Many physical signs can alert you to potential malnutrition. These symptoms often develop gradually, making them easy to miss in the early stages. Paying close attention to a person's body and physical well-being is crucial for early detection.

Key physical signs to watch for in adults include:

Unintentional weight loss: Losing 5–10% or more of body weight over a period of 3 to 6 months is one of the main indicators. This can cause clothes, watches, and rings to feel looser.
Muscle and fat loss: Visible wasting of muscle, particularly around the temples, clavicles, and thighs, is a clear sign of undernutrition.
Changes to skin, hair, and nails: A lack of essential nutrients can cause dry, flaky, or pale skin, as well as thinning, brittle, or easily pluckable hair. Nails may become brittle, ridged, or spoon-shaped.
Swelling: Fluid retention, or edema, can be a sign of severe protein deficiency. This may manifest as thin arms and legs with swelling in the belly and face, a condition known as kwashiorkor.
Slow wound healing: The body's inability to repair itself efficiently is a common symptom due to a lack of vital nutrients needed for tissue repair.
Weakened immune system: Malnourished individuals get sick more often and take longer to recover from illnesses.

Behavioral and Emotional Symptoms

Malnutrition doesn't just affect the body; it profoundly impacts mental and emotional well-being. Changes in a person's mood, concentration, and energy levels can be key indicators that something is wrong.

Common behavioral and emotional signs include:

Lethargy and chronic fatigue: Feeling tired all the time and having a lack of energy, even after a full night's sleep.
Apathy and irritability: A noticeable change in mood, characterized by a lack of interest in previously enjoyed activities or increased irritability and anxiety.
Poor concentration: Difficulty focusing on tasks and a general lack of mental clarity.
Depression: Low mood and persistent sadness, which can be both a cause and a symptom of poor nutrition.
Changes in appetite: A significant loss of appetite or a lack of interest in food and drink.

Unique Signs in Children

Malnutrition in children can have different manifestations than in adults, as it can interfere with proper growth and development. Early detection in children is especially critical due to the long-term cognitive and developmental impacts.

Specific signs to look for in children include:

Faltering growth: The child is not gaining weight or growing at the expected rate for their age, also known as 'wasting' or 'stunting'.
Low energy levels: Children may appear listless, lethargic, or tire more easily than their peers.
Behavioral changes: Uncharacteristic irritability, anxiety, or decreased social responsiveness.
Developmental delays: Slower behavioral and intellectual development, which can lead to learning difficulties.
Swelling in legs or stomach: A symptom of severe acute malnutrition (kwashiorkor).

Comparison of Common Symptoms: Undernutrition vs. Overnutrition

It's important to remember that malnutrition encompasses both extremes of nutrient intake. While undernutrition is often more visible, overnutrition can also cause significant health problems.


Symptom	Undernutrition	Overnutrition
Weight	Low body weight; unintentional weight loss	Overweight or obesity; unintentional weight gain
Energy	Chronic fatigue; feeling weak	Difficulty with physical activity; tire quickly
Body Composition	Visible loss of fat and muscle mass	Increased body mass index (BMI); excess fat
Appearance	Dry skin, brittle hair, ridged nails	Increased sweating; difficulty breathing
Immunity	Frequent infections; slow recovery	Increased risk of chronic disease

Causes of Malnutrition and When to Act

Malnutrition can arise from a multitude of factors, including medical conditions, financial constraints, social isolation, and mobility issues. Chronic diseases like cancer or Crohn's disease, as well as mental health issues such as depression, can affect a person's appetite or nutrient absorption. For older adults, reduced mobility or the loss of a partner can lead to eating less or struggling to prepare meals.

If you suspect someone is malnourished, it is crucial to act. Encourage the individual to see a doctor for a proper diagnosis and treatment plan. A healthcare professional can assess their nutritional status through measurements, blood tests, and a discussion of their diet and health history. If there are concerns about neglect or the person cannot advocate for themselves, contact the relevant safeguarding authorities. Providing nutritious, easily prepared meals and snacks, and offering social support, can make a significant difference. In severe cases, hospital treatment or assisted feeding may be necessary.

Steps to Take If You Are Concerned

Encourage a medical visit: The first and most important step is to suggest a consultation with a GP or other healthcare provider.
Offer practical support: If mobility is an issue, help with grocery shopping or cooking. If the person is isolated, share meals with them or organize meal delivery services.
Enrich their diet: For those with poor appetite, focus on nutrient-dense foods. Fortify meals with ingredients like milk powder, cheese, or nut butter to increase energy and protein content without increasing portion size significantly.
Consider a dietitian referral: A doctor may recommend consulting with a dietitian to create a tailored diet plan and suggest supplements if necessary.
Monitor and track: Keep an eye on their weight and overall well-being. Look for signs of improvement once a treatment plan is in place.

Conclusion

Learning how to tell someone is malnourished is the first step toward intervention and recovery. Malnutrition is a multifaceted issue with a wide range of physical and psychological symptoms that can be easy to overlook, especially when they develop slowly. By being attentive to the signs of unintentional weight loss, mood changes, and other subtle health indicators, you can help a loved one get the medical attention they need. Early diagnosis and a comprehensive treatment plan can significantly improve a person's quality of life and prevent severe, long-term health complications. The combination of a balanced diet, medical supervision, and compassionate support is the key to combating this silent health crisis.

Merck Manuals: Undernutrition

Frequently Asked Questions

Yes, absolutely. Malnutrition is an imbalance of nutrients, and a person can consume excess calories while still lacking essential vitamins and minerals. This is often called 'overnutrition' and can lead to its own set of health problems.

Early signs often include a loss of appetite, feeling tired and weak all the time, and a general lack of interest in food or drink. Subtle, unintentional weight loss may also occur, which can be hard to notice at first.

In children, signs often include faltering growth (not growing or gaining weight at the expected rate), irritability, and lower energy levels than other children. Severe cases can also cause swelling in the legs or stomach.

Malnutrition can lead to mood changes like apathy, irritability, and depression. People may also have poor concentration and feel lethargic.

Encourage them to see their doctor or a dietitian. You can also offer practical support by helping with grocery shopping, preparing meals, or arranging for a meal delivery service. Focus on nutrient-dense foods and encourage a supportive eating environment.

Hospital treatment may be needed in severe cases, especially for young children or individuals with complications. This can involve careful refeeding, and in some instances, feeding tubes or intravenous nutrition may be used under medical supervision.

Recovery time depends on the severity and cause of the malnutrition. Severe cases can take weeks of careful refeeding, often requiring close medical monitoring to prevent complications like refeeding syndrome. Mild cases can improve with dietary changes and supplements under a doctor's guidance.