Abstract Childhood malnutrition is highly prevalent in developing countries. Globally 35% (3.5 million) of child deaths before the age of five years were attributed to under nutrition in 2004. Vulnerable communities generally consume a diet based mainly on plant-based staples, and a low consumption of animal source foods, fruit and vegetables predisposes these communities to micronutrient deficiencies. In this paper, South African data is used to illustrate the poor diet and consequences thereof in vulnerable communities. Childhood malnutrition and maternal overweight often co-exist in the same community. Dietary modification strategies to address malnutrition should therefore focus on the nutritional quality of the diet, rather than on energy content only. Animal foods are particularly rich sources of bio-available iron, zinc and vitamin A (the micronutrients of greatest concern), and these nutrients are difficult to obtain in adequate amounts from plant foods alone. Foods of animal sources (particularly muscle tissue) also enhance the absorption of the less bio-available non-heme iron. Dietary modification strategies need to be introduced from a very young age. In the developed world, commercially available baby products play an important role in meeting the nutritional requirements of infants, but in developing countries cost and possible contamination (bottle feeds) prohibit the use of baby products. Addition of small amounts of foods of animal sources can improve the nutritional quality of the diet, as well as the nutritional status and functional outcomes of vulnerable populations. A moderate increase in the consumption of animal source foods will provide critical nutritional benefits without a significant increase in the risk of chronic diseases in the poor. Constraints for frequent consumption of animal source foods include availability, affordability and lack of cold storage facilities. Adequate dietary intake is essential for good nutrition, but frequent infections can also lead to malnutrition. The underlying causes of malnutrition, i.e. inadequate care on the one hand, and insufficient health services and an unhealthy environment on the other hand, should also therefore be addressed.