Malnutrition: The Difference Between Undernutrition and Overnutrition
Shanthi Appelo, MS, RD
| 4 min read
Malnutrition is often associated with being severely underweight. However, anyone whose body is deprived of the nutrients it needs to maintain healthy tissues and organ function is malnourished. Malnutrition is a disease that involves suffering from either a lack of nutrients or an abundance of certain nutrients, which is why individuals who have obesity can be considered malnourished.
There are various forms of malnutrition, but the two main types are undernutrition or overnutrition.
Undernutrition
Characterized by a lack of nutrients and insufficient energy supply, undernutrition can occur if a person doesn’t eat a balanced diet or if their body struggles to absorb enough nutrients from food. It’s a condition that can be broken down into two subsets:
Macronutrient undernutrition:
Macronutrients are the three nutrients the body needs in large amounts: fats, carbohydrates and proteins. All three are part of a healthy diet and are integral in helping the body maintain its systems and structures. The average healthy individual should eat 0.36 grams of protein per pound of body weight, but increases with higher activity levels. The Dietary Guidelines for Americans recommends that a person get between 45% and 65% of their calories from carbs and 20% to 35% of their total daily calories from fat. Without all or even one of these macronutrients, tissues in the body can break down and a shutdown of nonessential functions can occur to preserve low energy.
Micronutrient undernutrition:
Micronutrients allow the body to produce enzymes, hormones and other substances that are essential for proper growth and development. They include vitamins, including Vitamin A and Vitamin D, and minerals, such as iron and calcium, which are often lacking in the average diet.
Signs of undernutrition can include:
- Brittle hair, hair loss and hair pigment loss
- Changes in skin pigmentation
- Dry skin, bruises, rashes and lesions
- Frequent and severe infections
- Low body temperature
- Low body weight
- Low heart rate
- Stunted growth (in children)
- Unintended loss of fat and muscle
Overnutrition
An excessive consumption of nutrients is known as overnutrition, which includes the effects of being overweight and obese. Overnutrition leads to an imbalance between the amount of energy the body stores and the amount of energy the body breaks down. Like with undernutrition, overnutrition has two subsets:
Macronutrient overnutrition:
When an individual eats an excess amount of protein, carbs and fat, their bodies store these macronutrients away as fat in the body. When fat cells grow and become enlarged, an individual can suffer from obesity and various non-communicable diseases (NCDs) like high blood pressure, diabetes, coronary artery disease and stroke.
Micronutrient overnutrition:
This type of overnutrition is less common than macronutrient overnutrition, but it is possible to consume too much of a specific vitamin or mineral. Taking mega doses of nutritional supplements (more than is recommended) can be toxic to the body.
Signs of overnutrition may include:
- Cardiovascular disease
- High blood pressure
- Insulin resistance
- Obesity
Who is at risk of malnutrition?
Malnutrition is a global problem that can affect anyone, but certain populations are more at-risk of undernutrition than others. People from low-income communities with fewer resources may suffer from undernutrition. In some communities, access to fresh fruits, vegetables, minimally processed animal products and whole grains is limited, making it more difficult to eat a healthy diet where they live and work.
Children and the elderly who can’t always advocate for themselves and may also be at risk of undernutrition. Those who are chronically ill and suffer from a decreased appetite or inability to absorb food are also susceptible to undernutrition.
Individuals with sedentary lifestyles and poor eating habits are candidates for overnutrition. A general lack of nutritional knowledge, education and living in food swamps can contribute to overnutrition and lead to poor portion control, overuse of supplements and a generally poor diet.
Malnourishment prevention tips
The best way to prevent malnutrition is to eat a properly balanced diet. A diet that includes nutrient-dense whole foods packed with a variety of vitamins and minerals, fiber, healthy fats, carbs and other components like antioxidants, is recommended.
A balanced diet should feature foods from these core elements:
- Dairy or non-dairy alternatives
- Fats/oils
- Fruits
- Grains
- Lean protein
- Vegetables
The following nutrient-poor foods should be avoided or consumed on a limited basis:
- High-glycemic foods
- Ultra-processed foods
- Red and processed meats
- Refined grains
- Refined sugars
- Saturated and trans fats
- Sweetened drinks
Additionally, since poverty and a lack of diet control for some populations contribute to malnutrition, it’s a disease that needs to be fought with education and through worldwide policy and infrastructure changes. Learning more about the United States Department of Agriculture’s Food Assistance Program can help certain individuals or groups that may be at risk of malnutrition.
Shanthi Appelö is a registered dietitian and health and wellness spokesperson at Blue Cross Blue Shield of Michigan. For more health tips and information, visit AHealthierMichgian.com.
