Dietary changes a hundred years ago in Europe, America and Australia were needed to feed their growing industrial populations. By 1909 margarines were first made by the hydrogenation of marine oils and, later, vegetable oils as a substitute for butter, thereby introducing saturated fats. The demise of the highly nutritious herring and its oil's hydrogenation into margarines seems to have coincided with a big increase in coronary heart disease (CHD). The Japanese escaped such changes to their rice diet by the influence of the inevitable annual monsoon while southern Europe's CHD immunity may hinge on its permanent olive oil and vitamin C antioxidant staples. Britain's 'angina pectoris' probably arose following the enclosures which changed arable (strip) into animal farming in the middle ages but cases rose only slowly from Heberden's 100 in 1802 to McKenzie's 200 by 1923. It seems likely, therefore, that much of the sudden increase to 2000 reported by Maurice Cassidy in 1945, despite the impact of this century's increased longevity on CHD, will be due to dietary change together with smoking's increasing impact.