Why bananas increase cholesterol

Anything that increases postprandial (after-eating) blood sugar will increase the number of LDL particles in the blood.

An increase in LDL particles is an important factor in causing heart disease: The greater the number of LDL particles, the more opportunity they have to interact with the walls of arteries, contributing to atherosclerosis.

Carbohydrates increase small LDL, especially if postprandial sugar is increased. Here's another way carbohydrates increase LDL particles: The duration of time LDL particles hang around in the blood stream is doubled.

When blood sugar increases, such as after the 30 grams carbohydrates in a medium-sized banana, glycation of LDL particles occurs. This means that a gglucose (sugar) molecule reacts with a lysine residue in the apoprotein B of the LDL particle. This induces a change in conformation that makes it less readily recognized by the LDL receptor. Thus, the glycated LDL particle persists for a longer period of time in the blood stream.

LDL particles are therefore cleared less efficiently, numbers of LDL particles increase.