The World’s Healthiest Foods’ Quality Rating System Methodology

In order to quantify the nutrient richness of each of the World’s

Healthiest Foods in this e-book, The World’s Healthiest Foods book,

and the WHFoods.org website, a team of top nutritionists and I designed

the World’s Healthiest Foods Quality Rating System (“Rating

System”).

This Rating System qualifies foods as “excellent,” “very good” and

“good” sources of nutrients, providing you with a simple, yet reliable,

way to determine the nutritional attributes of a food. These quality

descriptions don’t just take a food’s nutrient contribution into consideration;

rather, they evaluate this nutrient contribution in relationship

to the amount of calories a food contains. This way you can

evaluate foods in terms of their ability to maximize your intake of

important nutrients without having to exceed your individual caloric

intake goals.

To help you better understand the categorization of foods as “excellent,”

“very good” or “good” sources of a particular nutrient, I want to provide

you with some background as to how these quality ratings were derived.

Rating System Categories

We began with a computerized analysis of the nutritional contents

of the World’s Healthiest Foods using the nutritional analysis software, Food Processor for Windows (ESHA Research, Salem, Oregon,

USA). In other words, we started with a food like carrots, and we

analyzed how much vitamin C, vitamin A, zinc, protein, etc. that

food contained in one commonly eaten serving.

For each food we found the %Daily Value (DV) contribution of each

nutrient, as well as the food serving’s %DV contribution of calories

(for more on DV, see below); the comparison of the two became the

Density, and is the first (and most important) part of the formula to

determine the food’s quality rating. We then picked a simple, threecategory

system for rating all foods: “excellent,” “very good,” and

“good.” The definitions of these rating qualifications are as follows:

Excellent Density>=7.6 And DV>=10% Or DV>=75%

Very Good Density>=3.4 And DV>=5% Or DV>=50%

Good Density>=1.5 And DV>=2.5% Or DV>=25%

In reality, the goal that each individual should strive for in terms of

daily nutrient and caloric intake varies depending upon his or her

personal needs. Yet, to help individuals meet their nutritional needs,

government agencies have created standard recommendations for

intake. The most up-to-date ones in the U.S. are those created by

the Institute of Medicine and are known as the Dietary Reference

Intakes (DRIs). Yet, since these DRIs can have many values for each

nutrient (varying by age, gender and whether a woman is pregnant

or lactating), we chose not to use these as our Daily Value (DV)

standard. Rather, for most nutrients we chose to use the U.S. Food

and Drug Administration’s “Reference Values for Nutrition Labeling”

as our standard for DVs. These are the values used by food manufacturers

in the “Food Facts” portion of their product’s label.

For other nutrients, such as for those where there were no “Reference

Values,” we derived a DV based upon the latest research or opinion

of nutrition science experts. With respect to omega-3 fatty acids, for

example, we adopted the standards set forth in a 1999 workshop

conducted at the National Institutes of Health (NIH). The workshop participants—who included prestigious contributors in the field of

nutrition science including Artemis Simopoulos, MD, Alexander

Leaf, MD, and Norman Salem, Jr., Ph.D—concluded that at least

1.2% of daily calories should come from omega-3 fatty acids, including

1% from alpha-linolenic acid and 0.1% each from EPA (eicosapentaenoic

acid) and DHA (docosahexaenoic acid). When translated

into the context of an 1800-calorie diet, this workshop standard

represented a recommendation of 2.4 grams of omega-3 fatty acids

per day, which we adopted as our food and recipe rating system

standard, given that we use 1,800 calories as the reference diet for the

Rating System. (The 1,800 calories chosen as the reference diet is

based upon the Institute of Medicine’s recommendation for sedentary

women, age 31-50.)

Total Nutrient Richness Chart

Once the density ratings for each food were calculated, I wanted to

create a quantitative way that each food’s density could be compared.

This was the number that was to become the Total Nutrient Richness,

featured on page 41. The number is a reflection of how many “excellent,”

“very good” and “good” ratings a food had. Each “excellent”

was assigned a value of 4, each “very good” a value of “2” and each

“good” a value of 1. These were added together to arrive at the Total

Nutrient Richness score.