High carbohydrate, low protein diet could be as effective as low calorie diet for health, researchers say

Updated

In the latest diet wars salvo, a new study has found low protein, high carbohydrate diets could be just as effective as low calorie diets at promoting a long life as well as a healthy heart and good digestion.

Scientists know the only proven way to live longer is to drastically restrict calories.

But now researchers from the University of Sydney's Charles Perkins Centre have found the same benefits with a low protein, high carbohydrate diet.

"We have known for many years that caloric restriction diets increase lifespan in all manner of organisms," Professor Stephen Simpson, academic director of the Charles Perkins Centre and report author, said.

"However, except for the fanatical few, no one can maintain a 40 per cent caloric reduction in the long term, and doing so can risk loss of bone mass, libido and fertility."

Scientists compared two sets of mice, those on calorie-restricted diets and those on a low protein, high carbohydrate diet.

"We've shown that when compared head-to-head, mice got the same benefits from a low protein, high carbohydrate as a 40 per cent caloric restriction diet," Professor Simpson said.

"If the same applies to us, this would mean healthier ageing, with more pleasure and less pain than caloric restriction."

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But there was one downside.

"While a low protein, high carb diet is likely to have beneficial effects later in life, it did increase hunger and the chance of weight gain," Professor Simpson said.

These latest findings about high carbohydrate, low protein diets follow earlier studies showing the regime promotes longevity and good cardio-metabolic health.

"We have again shown that changing the macronutrient composition of a diet is vitally important, and in this case is a more feasible intervention than caloric restriction for managing human health," Professor Simpson said.

Findings contradict documented benefits of fasting

The findings seem somewhat at odds with the latest diet trend, intermittent fasting (IF).

Drastically cutting kilojoules is reported to help you to lose weight, and some advocates say it reduces your chances of developing some chronic diseases and may even extend your life.

Associate Professor Amanda Salis, from the University of Sydney's Boden Institute of Obesity, Nutrition, Exercise & Eating Disorders, said research had found some forms of fasting really could help some people to lose weight.

In particular, there is strong evidence behind the popular IF diet, where you fast a few days of the week, but eat normally without restriction on other days.

"About 30 studies have looked at IF diets in healthy overweight or obese adults and they've consistently found that if you restrict energy intake periodically over time then you do lose weight," Associate Professor Salis said.

"The thing about the research with these diets is that there are so many variations of IF that are used and are successful, so there's no one best way - it's trial and error.

"But popular fasting diets are 5:2 [which involves eating normally five days and fasting for two] and alternate day fasting."

Topics: diet-and-nutrition, health, science-and-technology, academic-research, australia

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