Is a high fat diet the key to a long life?

The high fat diet scores again over carbs‚ this time for longevity and strength.

A US lab study shows that a high fat (or ketogenic) diet increases long life and physical strength compared to a high carb diet.

In South Africa‚ the Banting Diet – which is high fat and low carbohydrates – popularised by sports scientist Professor Tim Noakes‚ has attracted nearly half a million fans as well as critics.

While the latest experiment was conducted on mice‚ not men‚ mice results have long been applied in science to humans.

UC Davis School of Veterinary Medicine nutritionist Jon Ramsey said: "The results surprised me a little. We expected some differences‚ but I was impressed by the magnitude we observed: a 13% increase in median life span for the mice on a high fat vs high carb diet. In humans‚ that would be seven to 10 years. But equally important‚ those mice retained quality of health in later life."

Ramsey has researched ageing for 20 years‚ looking at factors that influence both rodents and humans.

“Calorie restriction (fasting) has been shown in several studies to slow ageing in many animals‚” said Ramsey‚ turning his attention to high fat diets in the study‚ published in Cell Metabolism this week.

In extremely low carb diets‚ the body shifts from using glucose for energy to fat burning as its main fuel‚ which Noakes and other scientists report have major health benefits‚ including reducing the risk of diabetes.

Noakes encourages people to eliminate all refined carbohydrates like sugar and many other carbs from their diets to revolutionise their health and weight.

Ramsey said of the lab trial: "We designed the diet not to focus on weight loss‚ but to look at metabolism. What does that do to aging?"

In addition to being stronger and living longer‚ the mice on the ketogenic (high fat/low carb) diet also had increased memory and motor function.

"Many of the things we're looking at aren't much different from humans‚" Ramsey said. “This study indicates that a ketogenic diet can have a major impact on life and health span without major weight loss or restriction of intake.”

In the long term‚ however‚ respected UCT medical specialists warn that the safety and benefits of the “one-dimensional” Banting diet are unknown‚ particularly in pregnancy and childhood.

“Our bodies need a range of nutrients sourced from a variety of food groups to survive‚” they advised in a public letter in 2014.