A recent systematic review and meta-analysis of 17 studies has found that low-carbohydrate diets are associated with a significantly higher risk of all-cause mortality in the long run. The research also found that low carb diets are not protecting against cardiovascular disease. The majority of the studies reviewed were done in Sweden and the United States.
Diets low in carbohydrates tend to have lower intakes of fiber and fruits and increased consumption of protein from animal sources, cholesterol and saturated fat, all of which are risk factors for mortality and cardiovascular disease. However, an increased risk of mortality from cardiovascular disease alone was not statistically significant in this study.
This study concludes, “given the facts that low-carbohydrate diets are likely unsafe and that calorie restriction has been demonstrated to be effective in weight loss regardless of nutritional composition, it would be prudent not to recommend low-carbohydrate diets for the time being.”