Thanks for the interesting reading! I took a dive and it turns out Operation Starvation was remarkably effective and arguably should have been used earlier [0]. Also it didn't actually lead to any deaths from starvation [1]. Here are some excerpts.
"After the war, the commander of Japan's minesweeping operations noted that he thought this mining campaign could have directly led to the defeat of Japan on its own had it begun earlier. Similar conclusions were reached by American analysts who reported in July 1946 in the United States Strategic Bombing Survey that it would have been more efficient to combine the United States' effective anti-shipping submarine effort with land- and carrier-based air power to strike harder against merchant shipping and begin a more extensive aerial mining campaign earlier in the war. This would have starved Japan, forcing an earlier end to the war." [0]&[2]
"While some of the main actors (the UK, the US, Germany, and Japan) escaped famine..." [1]
"In Britain, Germany, and Japan, rationing was effective; even though food availability was sharply reduced almost everywhere, few literally died of hunger. Britain and Germany managed to maintain food consumption per capita at about 3,000 calories throughout the war. In Japan consumption fell from a norm of 2,000 calories per capita before Pearl Harbor to 1,900 calories in 1944, plummeting to 1,680 calories by the war’s end." [1]
"After the war, the commander of Japan's minesweeping operations noted that he thought this mining campaign could have directly led to the defeat of Japan on its own had it begun earlier. Similar conclusions were reached by American analysts who reported in July 1946 in the United States Strategic Bombing Survey that it would have been more efficient to combine the United States' effective anti-shipping submarine effort with land- and carrier-based air power to strike harder against merchant shipping and begin a more extensive aerial mining campaign earlier in the war. This would have starved Japan, forcing an earlier end to the war." [0]&[2]
"While some of the main actors (the UK, the US, Germany, and Japan) escaped famine..." [1]
"In Britain, Germany, and Japan, rationing was effective; even though food availability was sharply reduced almost everywhere, few literally died of hunger. Britain and Germany managed to maintain food consumption per capita at about 3,000 calories throughout the war. In Japan consumption fell from a norm of 2,000 calories per capita before Pearl Harbor to 1,900 calories in 1944, plummeting to 1,680 calories by the war’s end." [1]
0: https://en.wikipedia.org/wiki/Operation_Starvation
1: https://voxeu.org/article/famines-wwii
2: https://www.anesi.com/ussbs01.htm