alrite i try to fact check the first statement and went on google scholar
https://www.nature.com/articles/1601819
https://www.nature.com/articles/29795/
"Undernutrition due to insufficient intake of energy and macronutrients and/or due to deficiencies in specific micronutrients impairs the immune system, suppressing immune functions that are fundamental to host protection."
"Nutritional deprivation suppresses immune function"
maybe it has long term effects on immune system but i dont think this is the time to make such experiment on ur own body.

also short term malnutrition has no long-term impact on you.