Functional Food Design Rules – part 1

First of all, the phrase “functional food design” implies that functional foods do not exist in nature and they have to be “designed” or formulated, or processed in some way, which is not exactly accurate. There are plenty of examples of such foods in their natural, unprocessed or wholesome state (different forms of algae come to mind here).

On the other hand, the term “processed food” currently has a negative connotation and in many cases it brings the picture of “fast food” in our minds. In my vocabulary “processed food” means a food that has undergone any type of processing – like grinding or milling, for example (raw peas and pea flour are both wholesome foods regardless of the fact that pea flour is processed).

So, to sum it up, in order for most foods to be called functional foods (according to how I see “functional”) they have to be processed in some way, or most of the time in many ways. Or in other words, functional foods most often than not will have to be formulated or designed.

In this article I am going to elaborate on two items: 1) What is “functional food”, and 2) What are the main requirements to make it functional.

First, what is “functional food”? There are two ways to answer this question – the commonly accepted and my own interpretation. I will give you  both.

The general definition is “Functional food or medicinal food is any healthy food claimed to have a health-promoting or disease-preventing property beyond the basic function of supplying nutrients.” According to this definition carrots are a functional food because of their naturally high level of the anti-oxidant beta-carotene. Tomatoes are, too – high levels of lycopene. In my book they are not quite there. A lot of stuff missing..

There are some quite disturbing examples of “functional foods” that fall into this category because of how the standard definition is worded. Example – calcium-fortified orange juice. OJ, and I don’t care how fortified it is and what it is fortified with, is still a sugar-rich liquid that ranks right up there with other artificial sugar-containing drinks on the market today.

I have a different definition of functional food. It is this: “A functional food must be designed to include all three macro nutrients in their most health-promoting forms and in sufficient quantities, based on the current understanding of human biology and biochemistry… and my personal knowledge of these. That’s the best I’ve got so far.

What are macro nutrients? Proteins, carbohydrates and lipids (fats). What are their most health-promoting forms and quantities, based on the most contemporary science? Let’s see..

1. Proteins – health-promoting forms (sources) and quantities in foods:

In proteins there are a total of 22 amino acids. Nine of them are considered essential – the human body can not synthesize them and they must be obtained from food. Currently, the most widely accepted method for determining the quality of dietary proteins is the PDCAAS method, which attempts to establish the amino acid requirements of humans and our ability to digest them.

PDCAAS references 11 amino acids (four of them in pairs of two) and suggests target levels of them in food. PDCAAS has many limitations, but nonetheless it provides a good reference guide to determine if the protein in food provides good value to the human body and its specific requirements.



One of the limitations of the PDCAAS reference that I’d like to point out, as it relates directly to functional food design, is the fact that it doesn’t account for the PDCAAS score of a mixture of two or more proteins from different sources, but rather of one source only. There is a way to determine the PDCAAS score of a mixture of proteins, but I prefer to think of it as combining sources of protein that complement each other and make up for otherwise low essential amino acids. I find this to be a lot simpler and the only practical way to go about it.

For example, proteins in grains (ex. rice protein) are low on the essential amino acid lysine, but are high in methionine. Legume proteins (ex. pea protein), on the other hand, are high in lysine and low in methionine. Combining both greatly improves the amino acid profile, and we don’t need PDCAAS calculations to see that. Combining any more inferior source of protein with any milk protein accomplishes the same, as well.

Forms (sources) of protein:

Grain proteins – ex. rice, corn, wheat (gluten) – 42*
Legume proteins – ex. pea, soy – 91*, white bean
Tuber proteins – ex. potato
Dairy proteins – ex. casein, whey or milk (mix of casein and whey – 121*)
Egg proteins – ex. egg white, whole egg – 118*
Meet proteins – beef – 92*, fish, shellfish

* PDCAAS of these protein sources

From the list above I use all but the last group of sources while formulating foods.

Desired minimum quantities of protein

The median requirement for protein per day is o.3g/lb (o.66g/kg) for adults. Coming from the bodybuilding world I personally consider this number to be a bit low, especially for very physically active individuals (ex. athletes). In demanding sports, like bodybuilding, the minimum requirements are a lot higher – somewhere in the range of 1.2g/lb (2.5g/kg) of lean body mass (LBM). LBM is not the total body weight of a person – it’s total weight less fat weight. So, as you can see, the actual numbers of required protein can be even higher when accounted for less metabolically active tissues like fat.

For example, a person weighing 150lb with a body fat percentage of 15 percent will have a LBM of 127.5lb. This is the number I like to work with when determining daily protein requirements.

So, if we take an average male with LBM of say 130lb, we work with the estimated median requirements for protein of o.3g/lb, and our average male eats 3 meals per day then this means that he needs about 40g of protein across these three meals. So, that comes to about 13g of protein per meal.

When designing functional foods I personally like to achieve at least 10g of protein per serving and the more usual target number for me is 15g per serving. This way even if the person ate nothing else during that meal but my food, he will have eaten at least a certain minimum (in my opinion) amount of protein, which will ensure that the body has enough for repair, cell renewal and other basic metabolic processes.

Some might wonder why we need protein in each food. It’s because 1) protein is vital for life, and 2) protein is the only macro nutrient that can not be stored in body stores for later needs (as opposed to carbohydrates and fats). In my view, protein is the major food group that the functional food design process must begin with. The other two come after it.

In summary, a serving of functional food (a food that has the potential to support and enhance the body’s functions)  should have at least 10g of protein per serving and more preferably 15g. Also, the protein must come from a single or multiple sources where the combined PDCAAS score is as close to 1 as possible. This simply means that the essential amino acids should be as close to the numbers in percentages, like the ones shown in the table above.

A good choice is whey concentrate/isolate, milk protein, casein, egg protein or a combination of grain and pulse protein, such as rice and pea. Potato protein isolate might be a great choice in its own as it comes really close to whey as far as amino acid profile goes.

In part 2 I will continue with determining the amounts of carbohydrates and the type of carbohydrates used in functional food design. In part 3 I will discuss fats (lipids) and how they apply in a thoughtful food formulation process.

– – –

Note: This is not meant to be an exhaustive guide. It simply represents my current knowledge and as I discover/learn more I will keep updating it. If you see any omissions or inaccuracies, please let me know by using the comments section below. That’s how we all learn.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.