Short summary: I talk to engineer Dave Feldman about what his dietary self-experiments taught him cholesterol in human physiology. His “N = 1” experimentation is not only very interesting and rigorous but most importantly, it cannot be explained by current mainstream notions in lipidology. We also discuss the implications that this may have for cardiovascular disease.
- Dave Feldman is known as the Christian Bale of nutrition for his extreme self-experiments where he ate 5,000 kcals per day, or fasted, ran half-marathons and did all of this see how his health and cholesterol responded – all in the name of science!
- Dave gives his cholesterol elevator-pitch
- Peter Attia says that “If you want to stop atherosclerosis, you must lower the LDL particle number. Period”. Dave doesn’t quite see it that way currently.
- The Friedwald formula – not a direct measure of LDLc but an inference – can both underestimate LDLc if the TG/Cholesterol is > 5 and overestimate it if the ratio is < 5.
- Dave observed that the “tightest [negative] correlation appeared with total fat in my diet and LDL-C cholesterol”. A 3-day timeframe had the tightest correlation of r2 = – 0.905.
- Dave observed his small LDL-p correlate with total fat quite strongly (r2 = – 0.718).
- Dave’s recent fasting experiment was cut short and small LDLp crashed ! Some would say this is counter intuitive.
- Dave asked people on Twitter to predict his next LDLc value to demonstrate reasonable accurate predictions could be made. Here was my guess! (I was 18 mg/dL off)
- Twitter questions
- Amy Berger (@tuitnutrition) asked “Do you know (or care to speculate) if anything else changes as dynamically & quickly as cholesterol w/dramatic diet change?”
- @MacroFour asked “Can its measurement be used as a proxy for inflammation?”
- @Waren_G_DPT asked about the link between 11β-hydroxysteroid1 and cholesterol
- Cortisone is inactive and is converted by the enzyme 11β-hydroxysteroid1 into the active form, cortisol
- “cortisol in physiological concentrations is a potent stimulus of lipolysis and that this effect prevails equally in both femoral and abdominal adipose tissue.” Effects of cortisol on lipolysis and regional interstitial glycerol levels in humans
- “In metabolic syndrome, 11β-HSD1 is underactive in liver tissue and overactive in fat tissue. This results in a high rate of cortisol clearance, and low rate of regeneration” [Amber ketotic.org]
- I asked Dave to commen on a statement Reaven et al. made in a paper, saying “it is noteworthy that TG/HDL-C ratio and MetS identified as high risk a similar proportion of men and women but the TG x G index identified significantly more men (p < 0.001)” Comparison of two surrogate estimates of insulin resistance to predict cardiovascular disease in apparently healthy individuals