The study, which involved more than 15,000 Americans who were tracked for a quarter of a century, found that those who ate a low-carb diet (with less than 40 percent of daily calories coming from carbs) or a high-carb diet (with more than 70 percent of daily calories coming from carbs) were more likely to die during the study period, compared with those who ate a moderate-carb diet, with about 50 to 55 percent of their calories coming from carbs.
For example, based on the findings, the researchers estimated that from age 50, people who consumed a moderate-carb diet would have a life expectancy that was about four years longer than those who consumed a very low-carb diet (with an average life expectancy of 83 years for moderate-carb eaters versus 79 years for very low-carb eaters).