Saturated fat and large LDL 16. February 2010 William Davis (44) Here's a half-truth I often encounter in low-carb discussions:Saturated fat increases large LDL particlesFor those of you unfamiliar with the argument, I advocate a low-carbohydrate approach, specifically elimination of all wheat, cornstarch, and sugars, to reduce expression of the small LDL pattern (not to mention reduction of triglycerides, relief from acid reflux and irritable bowel, weight loss, various rashes, diabetes, etc). Small LDL particles have become the most common cause for heart disease in the U.S., exploding on the scene ever since agencies like the USDA and American Heart Association have been advising the public to increase consumption of "healthy whole grains." This has led some to make the pronouncement that saturated fat increases large LDL, thereby representing a benign effect. Is this true? It is true, but only partly. Let me explain. There are two general categories of factors causing small LDL particles: lifestyle (overweight, excess carbohydrates) and genetics (e.g., variants of the gene coding for cholesteryl-ester transfer protein, or CETP). If small LDL is purely driven by excess carbohydrates, then adding saturated fat will reduce small LDL and increase large LDL. If, on the other hand, your small LDL is genetically programmed, then saturated fat will increase small LDL. In other words, saturated fat tends to increase the dominant or genetically-determined form of LDL. If your dominant genetically-determined form is small, then saturated fat increases small LDL particles. So to say that saturated fat increases large LDL is an oversimplification, one that can have dire consequences in the wrong situation.