LOW CARB OR HIGH CARB? MOST RECENT RESEARCH IMPLICATES BOTH
-By JOSEPH EDUN
According to a recently published research in the Lancet, eating either a low-carb diet or a high-carb diet raises the risk of an early death. Researchers who pooled the results of eight large studies have found that eating a moderate amount of carbohydrates is best for a healthy lifespan. Less than 40% or more than 70% of calories from carbohydrates carried a higher risk of mortality. Not all low-carb diets are equal, however. People who ate a lot of meat and fats instead of carbohydrates, such as lamb, chicken, butter and cheese, had a higher mortality risk than those who got their protein and fats from plant-based foods such as legumes and nuts.
“Low-carb diets that replace carbohydrates with protein or fat are gaining widespread popularity as a health and weight loss strategy,” said Dr Sara Seidelmann, a clinical and research fellow in cardiovascular medicine from Brigham and Women’s Hospital in Boston, who led the research published in the Lancet public health journal. However, our data suggests that animal-based low-carbohydrate diets, might be associated with shorter overall life span and should be discouraged. Instead, if one chooses to follow a low-carbohydrate diet, then exchanging carbohydrates for more plant-based fats and proteins might actually promote healthy ageing in the long term.”
Dr Sara Seidelmann and her team carried out the observational research with more than 15,400 people, aged 45 to 64, from diverse socio-economic backgrounds from four US communities who were enrolled in the atherosclerosis risk in communities study. Those people filled out questionnaires on their eating patterns on two occasions, six years apart. Their health was followed up for 25 years, allowing for factors that might alter the results, such as smoking, income and diabetes. These results were pooled with seven other observational studies carried out across the world, involving a total of more than 430,000 people. They found that 50-year-olds eating a moderate carb diet, with half their energy coming from carbohydrates, had a further life expectancy of 33 years, which was four years longer than those on low-carb diets and one year longer than those who ate a high-carb diet.
The authors said they could not prove cause and effect, because of the nature of the studies. However, they said people who embraced western-type diets that heavily restricted carbohydrates often ate fewer vegetables, fruit, and grains and more animal proteins and fats. Some of those animal products have been implicated in stimulating inflammatory pathways, biological ageing and oxidative stress, and could be a contributing factor to the increased risk of mortality.
High-carb diets are common in Asian and poorer nations, they said, where people eat a lot of refined carbohydrates such as white rice. Those also contribute to a chronically high glycaemic load and worse metabolic outcomes.
“No aspect of nutrition is so hotly contended on social media than the carb versus fat debate, despite the long term evidence on health benefits firmly supporting the higher carb argument,” said Catherine Collins, an NHS dietitian.She added that the findings raise questions about the current hyping of low-carb diets for people with diabetes. “The feting and promotion of GPs promoting often bizarre low carb diets to manage diabetes has gained much media traction,” she said. “If nothing else, this study provides some redress to this one-sided debate, and adds caution to such practice for long term management.”