NASM CNC Chapter 18: Dietary Assessment and Body Composition testing

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    Chapter Goals:

    • Discuss the current guidelines for dietary health for the general public.
    • Find the differences in the habitual intakes of clients and the intakes that are conductive for their goals. 
    • Look at the similarities and the differences in the body comp assessment methods and also at their possible usefulness with your clients.
    • Find the importance that being consistent, repeatable, and accessible has over the sophistication and precision.

    Dietary Guidelines Foundations

    The department of health and human services along with the united states department of agriculture make the dietary guidelines for Americans that we look at for giving general advice regarding nutrition. The five guidelines are:

    • Follow an eating pattern throughout your lifespan that is considered healthy.
    • Have a focus of variety, amount, and density of nutrients when eating.
    • Limit your calories from additional sugar, reduce your intake of sodium, and limit the saturated fats.
    • Shift your diet to healthier beverages and foods.
    • Support an eating pattern that is healthy for all.

    Dietary Reference Intakes are the things on the nutrition labels that show the recommendations for the various nutrients as it has been found by the food and nutrition board of the institute of medicine. DRIs are like the RDAs. 

    Recommended dietary allowance = the average of the daily nutrient intakes that is enough for the requirements of nutrients for nearly all people in a certain life stage.

    Adequate intake = the average intake on a daily basis that is seen to be good enough for all the healthy people in a group. This is used when we do not have the RDA available to us. 

    Tolerable upper intake level = this is the highest average daily intake of nutrients that will not likely pose any risk of an adverse health effect on most people in the general population.

    Estimated average requirement = this is the average nutrient intake on a daily basis that is going to meet half of the people in a group’s requirements. 

    Acceptable Macronutrient Distribution Ranges are within the Dietary Reference Intakes. It is the recommendations of the percentages of macronutrients someone should have.

    Components of Healthy Eating Patterns

    The dietary guidelines that we just went over will focus on the importance of overall eating patterns, instead of the specific recommendations of nutrients. 

    • For adult women, we see a recommendation of 1,600 – 2,400 calories per day. 
    • For adult men, we see a recommendation of 2,000 – 3,000 calories per day. 

    When we look at our active clients, we see these to be less reliable and generally not accepted to be used by coaches for their clients. 

    The first problem with the caloric recommendations is the fact of not taking in the size of someone’s body as a variable. The second is that this only uses three different activity levels. This is bad because there are so many variances in activity. And then lastly, most athletes will exceed this level of activity you see used, so it is not good for them.

    RMR is the resting metabolic rate. This is the amount of energy that someone uses when at rest for the sustenance of the basic processes within the body. This is generally seen as a 24 hour period. 

    Foods to Emphasize

    The major food categories that we need to emphasize in our diets are going to be veggies, fruits, whole grains, low fat and fat free dairy, and then protein foods. These serve as a starting point for the evaluation of the quality of a client’s diet. 

    Variety of Vegetables

    These typically serve as nutrient dense foods that are a critical part of healthy eating. They will give us many nutrients like fiber and both types of vitamins, and of course important minerals. It is highly advised to eat vegetables, and also even more important that this intake is varied. This is how we will receive the full spectrum of beneficial nutrients that we need. 


    Like the vegetables, fruits will give us many vitamins and minerals, and a lot of fiber, too. It is recommended that we get at least half of our fruits from actual whole fruits instead of the juices alone. This is because the juices will lack that fiber.


    These should be included in any healthy eating pattern, and refined grains need to be limited. We should look for more 100% whole grain products rather than the others. 


    These products such as milk, yogurt, and cheeses will help to give some vital nutrients also. They are a solid source of calcium, phosphorous, and others. 

    Animal and Plant Protein Sources

    Both animals and plants can be a part of the total amount of protein we need. Animal products are usually going to be higher than the plants, though. Consuming a large variety of protein sources is more beneficial here as they have some variances in the nutrients they contain also.

    Foods to Limit

    We should emphasize those aforementioned foods, and then try to make sure to restrict or remove these from the diet, as they are less healthy.

    Trans Fat

    This is a form of fatty acid that is found in small amounts in nature and it is made through a process known as hydrogenation. These are found in many hydrogenated oils like margarine, some snacks, and also desserts. 

    Added Sugar

    This is a big one. This is done in the form of syrups and table sugar being added to sweeten things. It can be added to food or to drinks. They will not usually have any nutrients added to them, and only really have that added caloric load. Less than 10% of our daily calories should actually come from these added sugars, as these just increase the calories we get instead of adding any benefit to our diet. 


    This nutrient is essential in our diet and has many critical functions. But it is very easily found throughout many of the foods we eat, and because of that we have started to intake too much sodium throughout our days. Some foods can have one thousand mg of sodium in one serving. This is two thirds of your daily intake right there in one meal.

    Assessing Dietary Intake

    A dietary assessment with your clients is important for the identification of eating patterns and any changes in these. This is simply the analyzation of a client’s intake of food and beverage to see their calories and nutrients they receive. We see these done in the form of a daily recall, diet records, or questionnaires. 

    Methods of Dietary Assessment

    24 – hour Recall is a small interview in which the client would tell you the things that they ate in the last 24 hours by memory. A quick list is made, you discuss foods they may have forgotten in the list. The time and occasion of the foods is known. Food is described and then this is all reviewed, and the coach may probe for more answers. 

    Usual intake is done as a compliment to a recall or to a diet record. The person describes their essentially normal day of eating.

    Diet Records are very common for this assessment. It is a list of foods eaten in some specific time frame. But unlike the recall, these are listed as you go through that time frame. 

    Food frequency questionnaires are done to give a big picture of someone’s diet and show the food groups they get. 

    Monitoring Body Composition

    Body Composition is the makeup that is someone’s body. This is the major components of interest that are fat mass and fat free mass. And we have many ways to find these out. 

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    Methods of Assessing Body Composition

    BMI – the simple use of an equation to determine where someone is in terms of the general population. You find BMI by putting the weight in kilograms over the height in meters of the person. This gives you a number that is then categorized. 

    Bioelectrical Impedance is a rather normalized way to find these body compositions. This is done by using electrodes that shoot some electricity through the body and then calculate the fat and fat free mass someone has based on the results. This gives us the body fat percentage that we use. Many clients will see this with a lot of scales that are found in gyms or even at home. 

    Skinfold testing is the testing of the commonplaces on the body in which most people hold the majority of their fat. With these measurements made at the common skinfold sites, we use a formula to determine the body fat percentage of the individual. It is most of the time more reliable than the bioelectrical impedance, but it requires the person to be more skilled.

    Ultrasound is expensive, but it is the use of high-frequency sound waves to probe and visualize the parts of the body and then use this to make calculations on the body fat percentage and the body composition of the person. This could also be used for clients that may have region specific goals. 

    Circumferences are common and good for showing the growth or weight loss in specific areas. 

    Underwater Weighing is done by looking at the body’s volume when being placed underwater and using some calculations based on this information.

    Air Displacement is the use of air in the same form as underwater weighing. Both of these require a lot of space and equipment, and thus are less used by the general population.

    Dual Energy X Ray Absorptiometry is the use of x-rays to find the body composition.

    Infrared 3D Scanning has been growing in popularity lately. It uses infrared sensors to map the body and find the body composition.

    Some other methods are computed tomography, magnetic resonance imaging, hydrometry, and near infrared interactance. 

    Choosing the Best Methods for Your Clients

    This all depends on what is available to you, weighed together with your ability to spend money, and desire for accurate results.

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