The following graph is Figure 1 from Lack of suppression of circulating free fatty acids and hypercholesterolemia during weight loss on a high-fat, low-carbohydrate diet.
|Nice Insulin, shame about the FFAs.|
From the first link above:-
"Current ketogenic diets are all characterized by elevations of free fatty acids, which may lead to metabolic inefficiency by activation of the PPAR system and its associated uncoupling mitochondrial uncoupling proteins."
From the third link above:-
"Weight loss was similar between diets, but only the high-fat diet increased LDL-cholesterol concentrations. This effect was related to the lack of suppression of both fasting and 24-h FFAs."
See also Elevated plasma free fatty acids predict sudden cardiac death: a 6.85-year follow-up of 3315 patients after coronary angiography, and Circulating Nonesterified Fatty Acid Level as a Predictive Risk Factor for Sudden Death in the Population.
I think that's quite enough bad news for a Friday afternoon.
EDIT: So much for fat being a "clean-burning" fuel for the heart. Some people believe that, because dietary fats pass from the small intestine, via the Lacteals, to circulation at the Subclavian vein, this means that the heart prefers to burn fatty acids.
From Page 10 of HIGH CARBOHYDRATE DIETS: MALIGNED AND MISUNDERSTOOD:-
Human erythrocytes (red blood cells) contain cholesterol and it can contribute towards atherosclerosis. See https://twitter.com/Drlipid/status/496625195738619904.
See also Evidence for a cholesteryl ester donor activity of LDL particles during alimentary lipemia in normolipidemic subjects. This is more evidence that very high fat meals are atherogenic, which is relevant to Ultra-high-fat (~80%) diets: The good, the bad and the ugly.