5 Most Reliable Ways To Measure Nutritional Status [Guide]


The way our bodies function every moment of every day, is dependent on nutrients. Nutrients from our food are the fuel that gives us energy, repairs our body and supports our growth. Nutrition is an essential need of life, and so our individual nutritional status is a critical indicator of health promotion and disease prevention.

Nutritional intake and controlling mechanisms such as satiety and appetite are highly complex physiological processes. Poor nutritional status may mean that someone is suffering from malnutrition or undernutrition. The spectrum of not consuming enough nutrients (including macronutrients and micronutrients) to overconsumption of food (yet still lacking critical nutrients) is vast, however it all falls under the umbrella of poor nutrition.

Long-term decline in nutritional status may result in a catabolic (deteriorating) metabolism and chronic low-grade inflammation which accelerates the loss of fat-free mass, impacts energy production, affects cellular renewal, lowers immunity, and reduces quality of life overall. 

With nutrients playing such an important role in our health, how do you measure nutritional status to determine whether you’re healthy, malnourished, or undernourished?

In this article, we’ll provide an overview of the five techniques, including both subjective and objective measures, used for comprehensive assessment of nutritional status. This will give you a general idea of the processes involved in completing a nutritional assessment, but it’s important to note that only clinical nutritionists and other qualified healthcare medical professionals will be able to provide an accurate review of your individual nutrition status.

1. Laboratory/Biochemical Analysis

A Clinical Nutritionist may recommend certain laboratory tests to gain detailed insights into a patient’s personal biochemistry (such as blood tests, urine tests, saliva tests, hair tests, stool tests, etc.). Key blood markers such as complete blood count, liver function tests, lipid profile and electrolytes, along with various vitamin and trace mineral assessments (such as Vitamin B12 and zinc), may help to detect deficiencies and provide valuable information regarding current nutritional status.

It is important to note that certain limitations exist within biochemical testing methods, particularly when it comes to the assessment of some nutrients. Not all nutrients have appropriate biomarkers and may be altered due to infection, inflammation, homeostatic regulation, age, and kidney function. A single biomarker measurement is also not suitable to assess total body status for some nutrients, as in the case of iron. To achieve a more comprehensive insight into iron status, multiple markers such as serum ferritin, transferrin saturation, TIBC and transferrin receptor should be tested.

Laboratory testing must always be interpreted within the clinical context to support the most appropriate individual insights and guidance. Such testing may assist with developing highly personalised and targeted treatment strategies to improve or optimise nutritional status.

2. Dietary Intake Assessment

To provide valuable advice, a Clinical Nutritionist must understand a patient’s existing diet – which foods they typically eat, and how often they eat them. An assessment of a person’s dietary intake and their individual habits is a useful tool for determining their nutritional status.

Quantifying food intake can be achieved in several ways, including 24-hour food recalls, weekly food diaries, food frequency questionnaires and more recently in the form of innovative technologies that allows the person to enter food data into a particular app or program.

Dietary assessment is just as important for reviewing a person’s macronutrient intake as it is for micronutrients. Reviewing the core macronutrients of proteins, fats, and carbohydrates along with daily and weekly servings of fruit and vegetables should form the foundation of dietary data. This also provides insights into general energy intake in the form of calories and sufficiency based on the individual’s energy expenditure and requirements. Whilst the accuracy of traditional dietary intake recall methods has often been a limitation in clinical settings, new and innovative ways of assessing dietary habits may be providing the key to better assessment and improved clinical compliance and patient outcomes. 

3. Anthropometry

Anthropometry is essentially the physical assessment of a person’s size, form, and functional capacities. One of the things that defines a species is the body structure of its organisms, which have a similar shape and size, and whose measurements are likely to fall within a certain range. When these measurements are breached, it can be an indicator of poor nutritional status. For example, someone who consistently consumes a poor diet may develop a large waist circumference, breaching the “standard” measurement that we would expect from someone healthy. Similarly, a child with limited access to food may have a smaller head size than expected, which can be measured as part of a nutritional assessment.

More specifically, anthropometry uses a measurement index to determine individual health and nutritional status, which can include a person’s height, weight, and resulting body mass index (BMI). Other measurements that may be used include skinfold thickness and body composition which encompasses fat mass, muscle mass, bone mineral mass and fat-free mass. When tracking a person’s nutritional status over a period of time, multiple measurements are taken. A common example of this is measuring the differences in a person’s weight between one date and the next.

4. Lifestyle/Quality of Life

Gaining an insight into a person’s lifestyle and overall quality of life is a key aspect of nutritional status assessment. Whilst these factors are not directly involving food, they can strongly influence someone’s dietary behaviours, preferences, and intake. This assessment may also encompass a patient’s clinical history, which forms both a subjective and retrospective description into their current state of health. Including:

In close relation to food intake is the daily or routine intake of prescribed medications, supplements or any other self-prescribed pharmaceutical or nutritional/herbal products. These are examined for drug-nutrient interactions and any side-effects that may impact nutritional intake, such as changes to appetite and other gastrointestinal symptoms. Smoking, vaping, and recreational drug use, even if socially, should also be discussed.

Core lifestyle habits such as sleep, energy, stress, exercise, and movement should always be assessed as there is a direct correlation with eating behaviour and nutritional status. Quality of life is also a subjective assessment; and yet it shouldn’t be underestimated in its importance in the clinical setting. It is based on an individual’s perception of well-being across key holistic foundations including physical, psychological, social, environmental, and spiritual or emotional areas of their life.

5. Physical Assessment

In detecting clinical signs and symptoms of potential nutritional deficiencies, physical assessment is a key objective method used. Some signs may be more specific to a particular disease state or deficiency, whilst others are non-specific and may require further investigations.

If a person has a nutritional deficiency, it may manifest itself in certain ways on the body and be further identified through asking the patient to describe any symptoms they might be experiencing. For example, an obvious sign of malnutrition is muscle wasting, which may be identified on various areas such as the shoulders, arms, thighs, and buttocks.

Some commonly identified physical signs of nutritional deficiencies, include:

It’s important to note that many of these clinical signs may be a result of other diseases and conditions, and not necessarily due to malnutrition or exclusively due to a certain nutritional deficiency.

Nutrients are critical for our health and well-being. They provide us with energy, repair our bodies, and help us to grow. The risk of nutritional deficiencies and insufficiencies is the negative influence on a person’s clinical outcomes, body function, autonomy and ultimately quality of life. Early detection through the key techniques listed can be incredibly beneficial for a person’s well-being in both the short and long term. Through an appropriate and comprehensive assessment Clinical Nutritionists can identify such deficiencies and then develop individualised care plans in a multidisciplinary approach to improve nutritional status and resolve any underlying barriers to optimal health.