comments by Dr Doug McGuff MD:
dougmcguffmd
Richard,
Remember, cholesterol measurements are really what I call “a downstream measurement of upstream phenomenon”. In John's case, he is naturally lean, which means his insulin sensitivity on his fat cells is relatively low. Also, his hormone sensitive lipase (the enzyme that mobilizes triacylglycerol from the fat cells) is probably more active than your average person. As a result of these two facts, he is going to have more circulating fat in his blood. He is less likely to store fat in the adipocytes and is more likely to mobilize them for utilization as energy. As a result, his total cholesterol and in particular his triglycerides will measure high. However, his LDL is lower because his systemic inflammation is lower and thus has a decreased need for a low-density protein to carry cholesterol to these sites of inflammation for patching.
This situation will occur in the very lean (below 9-10% bodyfat) and those making the transition to becoming a fat-burner. The cholesterol and triglycerides are not higher because of increased production in the liver (due to overconsumption of refined carbs in the face of full glycogen stores which requires fat conversion to protect against dangerous elevations of serum glucose). In the case of the fat-burner the numbers are higher because fat is slow to be stored and is easily released for use as fuel.
The triglycerides, rather than being stored in the fat cells where they stimulate inflammatory mediators, are dumped into the circulation where they go to the mitochondria of your cells for beta-oxidation to produce energy. The numbers by themselves are meaningless, the context in which they were collected means everything….which is why I don't measure.
To those that are actively losing weight while on a H-G diet, remember you are on a high fat diet (your own fat) which has to be in circulation to be used as energy. If you plunge a needle into a vein and take a sample of what is going on during this transition, the numbers are going to look funky and will absolutely freak out the average MD.
For a good explanation of what I am talking about, see the youtube clip of my lecture in Salt Lake City at http://www.bodybyscience.net. Go to clip #5 and the discussion of the above starts at about 4:50.
