Everybody knows lowering triglycerides is a good thing, right? But I’m thinking, if you decrease your level of circulating triglycerides you’re lowering a potent source of available energy and hence the propensity to fatigue. Perhaps there is a compensatory bonus for the body in doing so though. Am I thinking about this all wrong? Thanks.
ETA: link to column in question (?): How can I avoid getting old? - The Straight Dope
Yes, lowering triglyceride may lead to a reduction in energy supply (primarily to muscle), but there are other sources of energy. In fact, by removing or decreasing TG as an energy source for muscle (or, more accurately, by removing or decreasing free fatty acids as an energy source for muscle, since it’s in the form of FFAs that TG fuels the muscle), we “compel” the muscle to use glucose as fuel. But that’s a good thing!
By reducing FFA availability to muscle, and thereby forcing it to use glucose as its main energy source, one is decreasing insulin resistance. In other words, when the muscle cells are happily sated with FFAs, they will tend to ignore glucose, even in the face of adequate insulin. When FFAs are less available, then for the identical level of insulin, the muscle cells will take up more glucose. They will effectively be more sensitive to insulin.
There’s even another benefit which is at least as important. Specifically, since FFAs stimulate the liver to make glucose (again, even in the face of insulin), high levels of FFAs lead to abnormally high levels of glucose production by the liver. Of course, that in turn leads to higher glucose levels in the blood which ‘strains’ the pancreas by forcing it to produce more insulin. Eventually, such a strain on the pancreas may lead to its exhaustion, with diabetes as a result.
This is an important concept in metabolism and is sometimes referred to as the Randall Cycle.
Oops! Make that the Randle Cycle (not Randall).