How well do Europeans eat in terms of not consuming too much, avoiding overweight and obesity?
The following section describes the metrics on Energy Balance that was embedded in Deliverable 6.3.
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Performance metric 3: Energy balance
The food and nutrient based performance metrics (as defined above) capture the quality of the diet including the variety of foods and nutrients consumed. However, because they are standardized for energy, they do not capture the energy balance. BMI (Body Mass Index) is a measure of energy balance, and reflects the balance between energy intake and energy expenditure. To capture this piece of information, the percentage of a population with ‘normal’ weight will be used as a third performance metric. A situation in which every individual has normal weight is ‘ideal’.
Individual variables
In the national surveys that are used in SUSFANS, we collected additional information on several population characteristics, including height and weight. We are thus able to calculated individuals’ BMI and calculate average BMI for population. We have to note that these data are self-reported and not based on anthropometric measurements. Usually people tend to underestimate their weight when it is self-reported. However, this bias is expected to be present in all countries and therefore comparison across countries should be less biased. Also these difference are expected to be relatively small. For example, in the Czech Republic differences between self-reported and measured normal weight ranged from 7.7-9.6% (Čapková, 2016).
Performance metric
BMI is calculated by dividing an individual’s weight (in kilograms) by his or her height (in meters squared). While it is not a perfect measure,4 it is the most common method to quantify weight across a range of body sizes in adults. Using BMI, individuals can be classified as normal weight (18.5–24.9 kg/m2), overweight (25–29.9 kg/m2), and obese (>30 kg/m2) (WHO, 1995). It reflects both health and nutritional status and predicts performance, health, and survival (WHO, 1995). BMI is often used as a proxy for body fat in large population studies. Correlations between BMI and more direct measures of body fatness are generally strong (r>0.70) (Flegal, 2009; Ranasinghe, 2013; Ablove, 2015; Bradbury 2017).
All the performance metrics for balance and sufficient diets and the underlying indicators and model variables are provided in Table 5 (see D6.3).
Extrapolation to EU and metric quantification for scenarios
We have data available for 4 countries (Czech Republic, Denmark, France and Italy). These countries represent the different regions in Europe (North, east, South and West) and account for ~30% of the European population. To estimate the performance metrics on the EU level we suggest taking the average of those four countries. If data becomes available for other EU countries (EFSA comprehensive database), it can be included.
The details above refer to how the metrics are calculated for base year 2010. To compute metric values for different scenarios the approach involves downscaling MAGNET results. In SUSFANS (D9.5/D10.3) diet scenarios are run for 2020 to 2050, which lead to changes in food consumption patterns expressed as a percentage change (MAGNET model results) for each FoodEx2 code. To be able to apply this change to the National survey data for baseline year 2010, we need a baseline consumption (in g/d) for each food item in each country. However, the national surveys that we use are from different years. Therefore, we constructed in each country, four subgroups based on age (<50 years vs ≥50 years) and sex (male vs female). These subgroups were used to standardize the national dietary surveys of the four countries, to the baseline year 2010 based on these demographics.