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Several studies actually do suggest that psychological stress can trigger an increase in blood cholesterol levels. The exact reasons why stress is associated with a raised cholesterol level are not fully understood. One possible explanation is that stressful situations cause the body to attempt to produce more energy (fatty acids and glucose), requiring increased production of LDL ("bad" cholesterol) by the liver.
Another significant factor is that stress tends to increase unhealthy behaviors and lifestyle choices, including eating an unhealthy diet, smoking, and inactivity, all of which are associated with higher cholesterol levels and an increased risk of heart disease.
"Management of elevated low density lipoprotein-cholesterol (LDL-C) in primary prevention"