Britannica Sources used in this answer

Why does persistent hunger increase a person’s susceptibility to disease?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

USDA MyPlate dietary guidelines — human nutrition MyPlate, a revised set of dietary guidelines introduced by the U.S. Department of Agriculture (USDA) in 2011, divides the four basic food groups (fruits, grains, protein, and vegetables) into sections on a plate, the size of each section representing the relative dietary proportions of each food group. The small blue circle shown at the upper right illustrates the inclusion and recommended proportion of dairy products in the diet.

Persistent hunger, or chronic undernutrition, increases a person’s susceptibility to disease primarily by undermining the immune system.1

When the body is deprived of essential nutrients—particularly protein—it cannot maintain normal immune function. This deficiency often leads to the atrophy of the thymus, a vital organ for immune development, which results in a shortage of helper T cells. Consequently, both antibody responses and cell-mediated immunity are significantly impaired, leaving individuals, especially children, highly vulnerable to infections such as measles and diarrheal diseases.2

Beyond specific immune cell depletion, malnutrition generally weakens the body's physiological defenses, making it difficult to resist or recover from illness. While the damage to the immune system can be severe, it is often reversible if adequate nutrition is restored, allowing the body to rebuild its metabolic and immune functions.342