Eating a lot of saturated fat makes your bad cholesterol go up.

Dietary intake of saturated fatty acids increases circulating levels of low-density lipoprotein (LDL) cholesterol in humans through upregulation of hepatic cholesterol synthesis and reduced LDL receptor expression.

Historical human populations consuming diets high in saturated fat from animal sources likely had higher circulating LDL cholesterol levels than contemporary populations, yet exhibited negligible rates of atherosclerotic cardiovascular disease.

Eating less saturated fat, like from butter and red meat, tends to go along with lower levels of 'bad' cholesterol in the blood.

Saturated fat raises LDL cholesterol, but mostly the 'bigger, fluffier' kind that doesn't clog arteries as much as the small, sticky kind.

When African Americans eat less saturated fat (like butter and fatty meat) and more carbs (like fruits and whole grains), their bad cholesterol (LDL) goes down, but another dangerous blood fat called Lp(a) goes up—so one risk goes down while another goes up.