A few days ago, I decided to get another blood test. The results are in. Most numbers are the same. But two numbers stick out like an ugly Christmas sweater in June: LDL and total cholesterol. They went up! But why?
I don’t really know why. But I have a few theories:
I lifted weights the morning before the test. Doing high-intensity weightlifting in a fasted state could cause more LDL to circulate through the blood. LDL carries, among other things, triglycerides, to the muscles. Since my body operates mainly by burning fat, triglycerides are mobilized and sent to the muscles via LDL. Since my blood test was only an hour or so after my workout, it’s plausible that I would still have high levels of LDL circulating in my blood. I did not work out the mornings of my previous blood tests.
I fasted for longer. 15 hours this time. I only fasted for 12 hours before my previous two tests. Perhaps my body burned through its glucose stores (lifting weights) and is in full-on fat burning mode; mobilizing a larger fleet of LDL trucks to deliver triglyceride packages to my fat-adapted muscles.
More Meat, Fewer Carbs?
I’m eating more meat and fewer carbs. Not just any meat, but fatty meat. The kind that’s full of saturated fat. Does eating more meat raise LDL? There is solid evidence pointing to eating saturated fats as the best way to increase HDL. However, I have yet to see strong enough evidence that increased saturated fat consumption raises LDL. In many studies, it has the opposite effect.
Too much meat?
It’s possible I’m over-doing it with meat. Not because of the increased fat consumption, but the protein. I’m not tracking what I eat. Perhaps the amount of carbs I’ve cut is less than the amount of protein I’ve added. Thinking back, some days it feels as though I’m eating past the point of full.
Fluke. Maybe this LDL reading is a fluke. We really don’t know for sure what causes variations in LDL readings, especially when one is on a low carb diet. It’s entirely possible I take another test tomorrow and my readings are “normal” again.
Is this a bad thing?
I don’t think so. My HDL and Triglycerides are essentially the same. Secondarily, my HbA1C and glucose measurements are still fine.
The correlation between high LDL and cardiovascular disease is weak. In fact, the evidence tilts in favor of high LDL being a good thing. Old studies have been re-examined to raise the possibility that high LDL is linked to reductions in risk for the four major killers: cancer, stroke, and Alzheimer’s disease.
Take a look this Framingham Offspring study. As Dave Feldman points out in a recent post, the study found if your triglycerides are less than 100 and your HDL is more than 40 (more than 50 for women), then your risk of CVD is the same whether your LDL is above 130 or below 100!
Focus on two numbers
The important factor here is my Triglyceride to HDL ratio. It’s under one, which means my metabolism is healthy – my carb consumption is low and my saturated fat consumption is high. If you believe, like I do, that the big four – heart disease, stroke, cancer, and Alzheimer’s – are metabolic diseases that stem from over-eating carbs and under eating saturated fats, then I’m still cheating death.