In 1958 the Japanese ate an average of 2,837 kcals per day, 84% from carbohydrates, 11% from protein, 5% fat. At that time they had a rate of CHD in men aged 35-64 of 50 per 100,000. Cholesterol levels were 3.9mmol/l. Not bad you may think, however their problem lay with haemorrhagic stroke. The rate of stroke in men aged 60-65 was 1,334per 100,000 in 1960.
By1995 cholesterol levels had risen to 4.9mmol/l. CHD in men aged 35-64 had fallen to 36 per 100,000, and astonishingly stroke had fallen to 17% of the 1960 levels at 226 per 100,000. The new average diet consisted of 2,202 kcal, 62% of which was carbohydrate, 18% protein, and 20% fat. They had been told to eat more saturated fat to improve blood vessels’ integrity (Dr. Malcolm Kendrick, 2011).
That's a drop of carbohydrate in real terms, from 2383 kcal to 1365 kcal, an increase in fat from 141 kcal to 440 kcal, and protein from 312 kcal to 396.
Admittedly coming from the other direction, how do those rates of success compare to statin trials and low-fat dieting?