You Can't Evaluate Nutrition From One Questionnaire

Tips & tricks
An accurate and reliable measurement of food energy and nutrient intake is the first and foremost step in order to optimise nutrition and evaluate its impact on health outcomes. But what is the best way to do that? 

Usual instruments used both by researchers and nutrition professionals include Food Frequency Questionnaire (FFQ), 24-hr food recall, and food diary. All of these methods have their advantages and disadvantages, so let’s discuss them in some detail.

Food Frequency Questionnaires became a staple of epidemiological research in the 1980s, but since then their numerous disadvantages have come to the fore, putting the whole validity of this method into question. FFQ is a list of 80 to 120 foods and beverages and respondents might be asked on the frequency of their consumption and portion size over the period of the last month, three months, or six months. When FFQ was introduced, its advantage was that it gave the respondents and researchers a clear structure, unlike the previously-used open-ended questionnaires. However, the disadvantages of this approach are almost too numerous to mention. The first and foremost is that accurately completing an FFQ requires a person to have a good memory and recall of specific events. The limited number of foods and beverages means that the FFQ may not capture the eating patterns of many people. FFQ also includes no information on how the food was prepared, which also influences the data. All in all, the issue of FFQ’s unreliability has long been a subject of discussion.

The 24-hr dietary recall is a structured interview intended to capture detailed information about all foods and beverages (and, possibly, dietary supplements) consumed by the respondent in the past 24 hours. Today, such interviews can be administered online and there are various programs, such as Intake24 or Myfood24, that enable this. There are two important things to know about this method. First, is that respondents using this method tend to underestimate their energy intake by 25% on average (when assessed with other tools). The second is that completing a single 24-hr food recall questionnaire is nowhere enough for assessing a person’s average diet, because it cannot account for the day to day variation.

The advantages and disadvantages of these approaches are best summarised in a study on assessing the nutrient status in athletes. And this brings us to the initial question. What is the best way to evaluate a person’s nutrition? Well, the best way is to do it over a much longer period of time than is usually common. Using the data from the unique Beltsville One-Year Dietary Intake Study, a group of scientists had calculated the true average intake for food energy and other dietary components for individuals. The findings varied by sex and from individual to individual (depending on how varied their everyday food intake was). The scientists discovered that accurate estimation of food energy intake takes 27 days on average for men (with variance from 14 to 84 days) and 35 days for women (with variance from 14 to 60 days). Estimating the accurate average intake of the macronutrients (protein, carbs, fat) all takes in excess of 30 days, and estimating the average intake of vitamins can take a good part of the year or even more. Vitamin A, while an outlier, is a good case in point. Estimating its accurate intake takes 390 days on average for men and 474 days for women. For vitamin C the numbers are 249 days for men and 222 days for women, and estimating calcium intake takes 74 days for men and 88 days for women. Even if we take the lowest number of days required for assessment, it will be 14 days for food energy intake, 10 days for carbs, and 13 days for vitamin B2.

Moreover, if we assign any goals to our nutrition (be it losing weight, adding muscle, or keeping healthy), constant control and assessment of food and nutrient intake becomes a must. This can only be achieved by keeping a food diary, but such a task places a heavy burden on the respondent. It is a time- and effort-consuming process that usually peters out within a month or two. This is where Abe Health comes into play. We make the process of keeping a food diary as easy as possible and we have developed a method for accurately determining vitamin and mineral intake that is aided by our proprietary AI trained by the best nutrition professionals. The AI is there to analyse your eating patterns and alert you if anything needs to change to keep on the way to your goals.