The research also linked diets both low and high in carbohydrates to an increase in mortality, while those who ate moderate amounts of carbs fared best. The findings suggest that replacing carbs with animal-based proteins is linked to a greater chance of mortality, while replacing carbs with plant-based proteins lengthens life expectancy.
Seidelmann warned about the widespread popularity of low-carb diets as a weight loss technique, with people giving up foods such as bread, pasta and potatoes.
To conduct their research, the scientists studied 15,428 people aged 45 to 64 from four U.S. communities with a range of backgrounds. The researchers found that, from age 50, average life expectancy was 83 years for those with moderate carbohydrate intake (50-55 per cent of daily calories), which was four years longer than those with very low carbohydrate consumption (less than 40 per cent of calories) who lived an average of 79 years.
This revealed similar trends, with participants whose overall diets were high and low in carbohydrates having a shorter life expectancy than those with moderate consumption.
Seidelmann suggested that, "instead, if one chooses to follow a low-carbohydrate diet, then exchanging carbohydrates for more plant-based fats and proteins might actually promote healthy aging in the long term".
The researchers estimated that from age 50, people eating a moderate-carb diet would live another 33 years, four years longer than those with very low carb consumption, and one year longer than those with high carb consumption.
The study authors noted, however, that the participants' eating habits were self-reported and only assessed at the start of the study and six years later. Whilst high carbohydrate diets (common in Asian and less economically advantaged nations) tend to be high in refined carbohydrates such as white rice, may also contribute to a chronically high glycaemic load and worse metabolic outcomes.
Experts say too much or too little of it can damage your health. The worldwide research shows that your mortality risk could be lowered if you follow a low-carb diet featuring plant-based proteins and fat.
They conducted a meta-analysis of studies on carbohydrate intake including more than 432,000 people from over 20 countries throughout North America, Europe and Asia.
Eating a diet which is low in carbohydrates could knock years off lifespan, a 25 year study suggests.
Low-carb diets, such as Atkins, have become increasingly popular for weight loss and have shown promise for lowering the risk of some illnesses.
After following the group for an average of 25 years, researchers found that those who got 50-55% of their energy from carbohydrates (the moderate carb group and in line with United Kingdom dietary guidelines) had a slightly lower risk of death compared with the low and high-carb groups.
The questionnaires relied upon people remembering what they ate, and it is this information that scientists used to estimate the proportion of calories they received from carbohydrates, fats and protein. As well, the study indicates that not all low-carb diets are the same when it comes to health, with plant-based ones being ideal.
However, the study's findings are observational associations that don't prove cause and effect. Essential nutrients should be consumed above a minimal level to avoid deficiency and below a maximal level to avoid toxicity.
Catherine Collins, an NHS dietitian, said that the "cult of low carb high-fat eating" was based on flimsy evidence that is considered "at odds with advice from WHO and government health bodies globally - including the UK's Public Health England - that recommend a carb intake to provide around half our daily calorie needs". In other words, a "sweet spot".