Malnutrition does not necessarily mean a lack of food - that is starvation. Malnutrition means a diet of food that makes someone ill because it does not meet their nutritional needs and will include people with eating problems like anorexia, many grossly overweight people and a significant number of elderly people have it through self neglect. Not to mention the number of people who become nalnourished in hospital because nobody has time to feed them.
DH lost 3 stone during an 8 week stay in hospital. He was overweight, it did him no harm. But I am still shocked that at no time was this excessive weight loss, 6lbs a week was neber a cause for comment or concern.
I am sure some malnutrition may be the result of inflation, but there are so many other causes of malnutrition.