Making Nutritional Assessment and Diatery Status

Nutritional Assessment – Dietary Status, BMI & Waist-Hip Measurement

How do you know if you get enough nutrients? – Doing Nutritional Assessment

To understand nutrition properly, we need to approach nutritional assessment scientifically. You can think of this as two processes:

  • Assessing our diet (measuring and assessing the food we eat)
  • Assessing our nutritional status (the body’s status in relation to diet)

Assessing our diet

A good method is to keep a ‘food diary’ for a week, and write down all the food and drink that you have had. By doing this it is possible to see how much of the macronutrients and micronutrients you have on an average day and compare this to recommended amounts.

Adjustments can then be made to increase or decrease any element of the diet as required. The overall goal is to achieve the optimum intake of nutrients to support health and well-being.

A variety of free online and purchasable software is available to check your food diary results, however the process can be quite long and confusing if you are not accustomed to scientific language and figures. For this reason, dietary analysis is usually best carried out and interpreted by a dietician or a qualified nutritionist and then explained in a consultation.

Some examples of online tools which might be useful are My Fitness Pal and My Diet Coach.

Food Diary to Make Nutritional Assessment
Food Diary to Make Nutritional Assessment


Assessing nutritional status

This entails make measurement of the body and blood and relating results to our diet.

BMI

A simple example is Body Mass Index (BMI) which calculates ‘weight for height’ of a person. The simple formula is Weight(kg)/Height(m)2. A BMI of below 19 usually means underweight while a BMI of over 25 indicates excess weight, above 30 obesity. This is a useful measure for groups of people, but can mislead for an individual. For example, a very muscular man may have a BMI of 30 but not have any excess body fat. Equally a pregnant woman may have a BMI of over 25 but in no way be overweight.

Waist-hip measurement

Perhaps a better way to do nutritional assessment, also very simple, is the waist to hip measurement. A simple measure of the waist (around the level of the navel) divided by the hip (around the level of the largest part of the buttocks). A high waist to hip measure (i.e. a big tummy compared to bum) is a sign of risk to health. On the other hand, a low ratio (small waist, bigger bum) is an indicator of lower risk to health.

From puberty to older age, women tend to have higher waist to hip ratios. This reflects a higher risk of heart disease. Research shows fat stored around the tummy area is risky for heart disease, but also for diabetes. Even keeping an eye just on waist measurement can be a useful indicator of disease risk.

Measure Your Waist and Hip Girth for Nutritional Assessment


Waist-to-hip ratio

Acceptable Not Acceptable
Excellent Good Average High Extreme
Women ˂ 0.85 ˂ 0.85-0.90 ˂ 0.90-0.95 ˂ 0.95-1.00 > 1.00
Men ˂ 0.75 ˂ 0.75-0.80 ˂ 0.80-0.85 ˂ 0.85-0.90 > 0.90

Total body fat measurement

We can also measure the percentage of our total weight that is body fat, on bioelectrical scales at the gym, the doctor or available to purchase. While these aren’t generally accurate to the clinical level, you can still get a good rough idea of your % body fat, and certainly see whether it is going up or down over time.

Blood tests

As well as measuring the body directly, clinicians and clinical nutritionists may also wish to measure blood.

Blood tests can be really thorough, but for nutritional assessment there are a smaller number of key tests to be aware of.

Cholesterol (total and LDL:HDL)

High cholesterol levels may signify a risk of cardiovascular disease. Dietary modification in the form of reducing saturated fat intake can be helpful in lowering cholesterol.

Blood glucose

Elevated blood glucose can signify increased risk for a range of disease including diabetes, cancer and heart disease. High blood glucose levels (hyperglycemia) are caused either by a failure to produce the hormone insulin (which normally lowers blood glucose), or a failure of insulin to function properly. In the case of a failure of insulin to function properly (insulin resistance), weight loss and exercise can be helpful. If insulin isn’t being produced it may need to be given in regular shots.

Haemoglobin levels

Low haemoglobin levels is known as anaemia. This can be caused by inadequate intake of iron in the diet. But also by too little of the B vitamins, especially Folate and B12, occasionally B6, and rarely copper.

If you wanted to test your blood at home there are a couple of useful resources. In the USA Walgreens offers blood testing kits and in the UK you can test with Thriva, who also offer great service.

Adam graduated from Queen Mary College London with a first class degree in physiology. Having completed an MSc in Nutrition at King’s College London he went on to research towards his PhD at the Royal London Hospital. He then established a career as a researcher and educator, teaching at major London Universities.
With expertise in anti-ageing, weight loss, clinical nutrition, sports nutrition and management of stress and fatigue, Adam has been featured on CNN, BBC TV & Radio and in UK national and local press.
Adam has published his research findings on multiple aspects of diet and health including diabetes, obesity, fatigue states, human performance and nutrition for healthy ageing.