woke this morning with an insight into a hoary chestnut i've been wrestling with for some time, why is it paleo apparently reverses insulin resistance and hence diabetes, but not heart disease. easy to understand why both paleo and high carb vegan prevent insulin resistance - fat in the blood inhibits uptake of fuel (carbs), so the bod either needs to be put on an alternate fuel source (fat), or dietary fat has to be reduced to a level where uptake of (carb) fuel is efficient. (from basic sports performance science, which also shows a fat fueled body cannot reach optimal levels of physical performance, a telling point perhaps).
the answer is actually obvious in retrospect, don't know why it eluded me for so long. heart disease is essentially the buildup of fat (plaque) in the cardiovascular system. paleos will argue that fat is not the cause of fat build in the body, insulin resistance is, and that is true, imo, to a relative, relevant point. so if fat consumption in the absence of insulin resistance is not the cause of fat accumulation, why is it not also reversing heart disease in the same way high carb vegan does?
the nutrient format of a whole plant diet may have something to do with it, but i think the primary reason a plant diet with no overt fat (7-10% of calories coming from fat) reverses cardiovascular disease is because the body (obviously) needs fat on an ongoing basis to function properly, and if it's getting only the bare minimum found in whole plant foods it will start consuming body stores of fat, including, of course, the fatty plaques and particles lodged in in the arteries, veins and capillaries. this would also explain why the long term 7-10% crowd is so lean, in fact the leanest population on the planet that is also "healthy", going by blood work and physical performance measures. the 7-10% whole plant diet essentially puts the body on a "fat fast", where it begins consuming it's stores. and since it's difficult (but not impossible) to over consume calories on a whole plant diet, this approach can be relatively unsophisticated - no calorie counting necessary, eat till full, all you want.
and over time, in that process, the body's internal satiety measures, which have been blown to smithereens by modern diet, will come into balance, and back into play. i was struck by the “pleasure trap” (recommended book) factoid that only humans and their domesticated animals have any problem whatsoever (of the millions of species on the planet) with under or overweight, demonstrating that correctly functioning autonomic satiety measures essentially work perfectly, given sufficient availability of native foods.
the corresponding question is how can this 7-10% population be so healthy with so little fat consumption, and i think the answer lies in the quality and density of micronutrients on this dietary approach. we are beginning to understand that supplementation is a problem because those supplemented micronutrients are not supported by a "whole organism host" (nutrients contained within whole unadulterated fresh foods). there are complex interactions here we can so far only posit, they are not well understood as yet, but the difference between whole food nutrition and supplement supported (otherwise inadequate) diet are anecdotally clear - when we discovered vitamins a little over a hundred years ago it was thought disease would be eradicated, but progression of industrial era disease has been exponential instead... so much for early scientific conclusion....
an interesting question remains: once cardio vascular disease has been eliminated from the body with a "whole plants only" 7-10% fat program (which is a fairly long process for complete eradication of advanced cases, probably 5--10 years, esselstyn probably has this data), is it then better for overall level of health to increase fat consumption again, and if so, to what general level? this is a question i have not seen asked or answered. the mcdougalls and esselstyns are adamant however, do they know something i don't, or are they unconsciously operating on "if a little bit is good, a lot must be better" ?
