How Malnutrition Affects the Brain:What Everyone Should Know About the Mental Impact of Not Eating Enough

When we talk about malnutrition, people often think of physical signs — weight loss, weakness, or fatigue. But one of the most profound (and often invisible) effects of malnutrition happens where we least expect it:

The brain.

Whether from an eating disorder like anorexia nervosa, ARFID, or even chronic dieting, undernourishment directly affects how the brain functions, feels, and processes the world. And when the brain is underfed, it can impact everything from emotions to memory, focus, sleep, and even personality.

Let’s take a look at how malnutrition changes the brain — and why nutritional rehabilitation is critical not just for the body, but for the mind.