Prediction of human dietary <i>δ</i>¹⁵N intake from standardised food records: validity and precision of single meal and 24-h diet data

<p>Natural stable isotope ratios (<i>δ</i>¹⁵N) of humans can be used for nutritional analyses and dietary reconstruction of modern and historic individuals and populations. Information about an individual’s metabolic state can be obtained by comparison of tissue <i>and</i> dietary <i>δ</i>¹⁵N. Different methods have been used to estimate dietary <i>δ</i>¹⁵N in the past; however, the validity of such predictions has not been compared to experimental values. For a total of 56 meals and 21 samples of 24-h diets, predicted and experimental <i>δ</i>¹⁵N values were compared. The <i>δ</i>¹⁵N values were predicted from self-recorded food intake and compared with experimental <i>δ</i>¹⁵N values. Predicted and experimental <i>δ</i>¹⁵N values were in good agreement for meals and preparations (<i>r</i> = 0.89, <i>p</i> < .001) as well as for the 24-h diets (<i>r</i> = 0.76, <i>p</i> < .001). Dietary <i>δ</i>¹⁵N was mainly determined by the amount of fish, whereas the contribution of meat to dietary <i>δ</i>¹⁵N values was less pronounced. Prediction of human dietary <i>δ</i>¹⁵N values using standardised food records and representative <i>δ</i>¹⁵N data sets yields reliable data for dietary <i>δ</i>¹⁵N intake. A differentiated analysis of the primary protein sources is necessary when relating the proportion of animal-derived protein in the diet by <i>δ</i>¹⁵N analysis.</p

Heterogeneous contributions of change in population distribution of body mass index to change in obesity and underweight

From 1985 to 2016, the prevalence of underweight decreased, and that of obesity and severe obesity increased, in most regions, with significant variation in the magnitude of these changes across regions. We investigated how much change in mean body mass index (BMI) explains changes in the prevalence of underweight, obesity, and severe obesity in different regions using data from 2896 population-based studies with 187 million participants. Changes in the prevalence of underweight and total obesity, and to a lesser extent severe obesity, are largely driven by shifts in the distribution of BMI, with smaller contributions from changes in the shape of the distribution. In East and Southeast Asia and sub-Saharan Africa, the underweight tail of the BMI distribution was left behind as the distribution shifted. There is a need for policies that address all forms of malnutrition by making healthy foods accessible and affordable, while restricting unhealthy foods through fiscal and regulatory restrictions