Dear Melaku,
You raise important points which have not been adequately addressed in the literature.
a) Low levels of mortality in Asia compared to Africa
The high mortality observed in Africa can partly be explained by the high prevalence of malaria in Africa compared to South Asia. But this may be only part of the story and I suspect there is also an issue with the measure of malnutrition.
Malnutrition can be best defined a state of nutrition in which a deficiency of energy, protein, and other nutrients causes measurable adverse effects on tissue/body form (body shape, size and composition) and function, and clinical outcome (1). Measuring malnutrition following this definition is difficult, however, and all epidemiological studies rely on measuring body size (weight-for-age), and a very rough measure of body shape, weight-for-height (WFH). This is a very imperfect approach and we should be aware of its limitations.
In the context of measuring obesity, it has proposed that Body Mass Index (BMI) which is close to WFH but easier to use in adults and to some extent reflects body shape, could be used to estimate the proportion of body fat and hence to define obesity. It has been observed for long, however, that this measure is imperfect and that the relationship between BMI and body fat is different across populations, to such an extent that using different cut-offs has been recommended to define obesity (2) (3) (4) (5) (6) (7) (8). These differences in the relationship between BMI and fatness seem related to body frame size and shape.
Curiously, the same discussion on the relevance of WFH to measure nutritional status did not take place when measuring malnutrition, although it looks likely that the relationship between body nutritional reserves (i.e fat and muscle mass) and WFH is likely to be influenced as well by size and shape of body frame. To my knowledge, there is only one study which looked at the effect of relative leg length on WFH and it found that WFH overestimates the degree of malnutrition in pastoralist populations who have relatively long length (9). On the other hand, it has been shown in Brazil that the low prevalence of wasting could also be used to a different body shape not directly related to nutritional status (10). It has been known for long as well that Indian children can have high body fat mass even when having low WFH and the term “thin fat phenotype” has been coined to describe this phenomenon (11).
Overall, this means that using WFH as a proxy measure of acute malnutrition can be misleading in some populations. I suspect that the high level of malnutrition suggested by wasting levels in South Asia does not adequately reflects the nutritional situation and may lead to wrong conclusions when doing comparisons with Africa.
b) Wasting prevention
I would agree with the World Bank document arguing that wasting prevention is difficult, at least in situations where there are no major problems of food insecurity. A full literature review, beyond the scope of this forum, would be needed to support this. A recent paper by the MRC team working in the Gambia however rather convincingly supports this statement. After 40 years of implementing multiple interventions to prevent malnutrition, there was an important decline in stunting but wasting remained constant (12). Maybe the difficulty to eliminate wasting can be related to problems of body shape as discussed above.
I hope this helps
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