Malnutrition is a broad term commonly used as an alternative to undernutrition, but technically, it also refers to overnutrition. People are malnourished if their diet does not provide adequate calorie and protein for growth and maintenance or they are unable to fully utilize the food they eat due to illness (undernutrition). They are also malnourished if they consume too many calories (overnutrition).

The World Health Organization cited that malnutrition is estimated to contribute to more than one third of all child deaths, although it is rarely listed as the direct cause. Lack of access to highly nutritious foods, especially in the present context of rising food prices, is a common cause of malnutrition. Poor feeding practices, such as inadequate breastfeeding, offering the wrong foods and not ensuring that the child gets enough nutritious food, contribute to malnutrition.

In Central Luzon, the 2014 result of Operation Timbang Plus shows that out of the total 1,488,047 preschool children weighed, 62,005 or 4.17 % are underweight while 22,027 or 1.48% are overweight. There was a very slight decrease in the percentage of underweight from 4.21% in 2013 to 4.17% in 2014. However, the percentage of overweight has increased from 1.39% in 2013 to 1.48% in 2014. Two reasons cited why there was an increase in the percentage of overweight preschool children nowadays are sudden boom of computer games and extensive growth of fast food in the region, especially in the provinces of Bulacan and Pampanga. Among the seven provinces of Central Luzon, the highest prevalence rate of overweight was found in Pampanga with 2.29% (5084) and among the fourteen (14) cities, Malolos has prevalence rate of 4.51% (900). On the other hand, high prevalence of underweight preschool children was found in the province of Zambales with 9.69% (7,577) and Malolos City again with 7.75% (1,546). Both areas have higher prevalence rate above the regional prevalence of 4.17% which may be considered alarming. To eradicate the malnutrition cases in Central Luzon, the Regional and Local Nutrition Committees of Central Luzon have integrated nutrition in their programs and activities in the so-called nutrition action plans (Regional and LGUs Philippine Plan of Action for Nutrition). Some of these programs are: 1) increasing food production activities among home, school and community; 2) full implementation of micronutrient supplementation and maternal and child health services; 3) provision of food assistance to malnourished preschooler and their families to improve their nutritional status; 4) reinforce utilization of fortified foods among households, market, schools and establishments; 5) massive campaign on proper nutrition and intensification of nutrition education, and; 6) other project innovations for the improvement of nutritional status of children Central Luzon.