This new study, of a cohort but also a meta-analysis that collects data from other studies, on the positive correlation found between low carb diets and reduction in longevity will certainly make people talk a lot about it : in other words, those who reduce carbohydrates would also reduce their expectations. of life of … four years. 
A study that appeared in The Lancet magazine analyzed a sample of over 15 thousand people who ate a normal-calorie but not excessively caloric diet, and compared the intake of carbohydrates in their daily diet with the risks of mortality from all causes, in the course 25 years old.
Here are the results:
– People who ate less than 40% of carbohydrates per day, together with people who ate more than 70% a day (therefore a high carb diet), were more likely to die early, compared to those who consumed around 50-55% a day.
– therefore low carb diets , which settle on a quantity of carbohydrates less than or equal to 40% of daily calories (from ketogenic to low carb up to the Zone diet) fall into the first case.
– people who ate vegetable sources instead of extra carbohydrates (lots of fruit and vegetables), while moderating simple and complex carbohydrates, do not have the same risk of early death. 
– people who ate sources of protein or fat instead of extra carbohydrates are likely to live less