For most people, a ketogenic diet leads to improvements in cholesterol, but there are sometimes transient rises in cholesterol levels during weight loss. During rapid weight loss, cholesterol that you had stored in your adipose tissue (ie, body fat) is mobilized, which will artificially raise serum LDL as long as the weight loss continues. To avoid being misled by this, the best time to check blood lipids is a couple of months after weight loss ceases. Total cholesterol includes HDL (the so called ‘good cholesterol’), which usually goes up 10-15% on a ketogenic diet. That said, some people have high calculated LDL cholesterol values even after weight loss stops. If this occurs, you should discuss further diagnostic tests with your doctor. Current research is looking at LDL cholesterol as a mix of different particle sizes, where the small ones are dangerous and the larger ones are not. With a well-formulated ketogenic diet, we see a shift away from the small dangerous LDL even when the total LDL goes up.