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High protein diet promotes healthy weight loss

by Rosanna Galvin

Dr Tom Wycherley.The festive season is now upon us and as we go to write our New Year resolutions, UniSA’s Dr Tom Wycherley (pictured right), has found a solution for those who have healthy weight loss on their list of goals for next year.

Based at the Sansom Institute for Health Research, the Postdoctoral Research Fellow’s latest study shows that a high protein diet may be the key to successful, healthy weight loss.

Steering away from the traditional diet format, which advises food consumption to be based on a 10-20 per cent protein, 45-65 per cent carbohydrates and less than 30 per cent fat formula, Dr Wycherley’s research reveals that when consuming a reduced energy diet over an average 12 week period and increasing the proportion of protein while reducing carbohydrate intake results in greater weight loss.

“A number of studies have shown that additional body composition benefits can be obtained within a weight loss diet by increasing the proportion of protein at the expense of carbohydrate, without altering the level of energy intake,” he said.

“Having said that, these results are not observed unanimously and no definitive large-scale well controlled studies have been conducted. We combined the results of all the studies that have looked at the effects of manipulating the carbohydrate/protein ratio of low fat, weight loss diets to see whether there was an overall advantage of higher protein diets.

“Our results showed that people who consumed a high protein diet achieved better weight loss. The studies went for an average duration of 12 weeks and over this time participants who followed a high protein diet lost 790g of additional body weight compared to those consuming diets with standard protein amounts.

“Furthermore, our research showed that high protein diets mitigated the typical weight loss induced reductions in muscle mass, which meant participants were losing more fat tissue, representing a better quality of weight loss.”

As well as weight loss, the study, which was published in The American Journal of Clinical Nutrition this month, showed that a high protein diet may have positive benefits for metabolism and appetite.

“Another significant finding was that resting expenditure was reduced to a lesser extent on a high protein diet. The majority of the energy you expend during the day comes from your resting energy expenditure and when you’re losing weight, it is typical for your resting energy expenditure to also reduce,” Dr Wycherley said.

“We also found that a high protein diet had an impact on satiety, which is the feeling of fullness. While we were unable to combine all the individual study results for satiety in our analysis, three of the five studies that measured it reported that participants felt fuller for longer on a higher protein diet.”

While the study offers a viable weight loss solution for those hoping to lose excess weight in a healthy way, Dr Wycherley says more research needs to be done to investigate whether high protein diets can provide long-term benefits.

“We would like to find out more about the magnitude of the results in the long-term. One of the key issues with weight loss is maintaining it over a long period of time. We don’t know at this stage whether losing more weight and having a better quality of weight loss translates to long term benefits for weight status and health,” he said.

“We also looked at the blood lipid profile, which showed a greater reduction of triglycerides with a higher protein diet. Elevated triglycerides have been associated with increased cardiovascular disease risk however we are still not sure if lowering triglycerides actually reduces the risk.”

Dr Wycherley’s next research project will investigate nutritional strategies for improving health outcomes in remote Indigenous Australians, after he was recently awarded a four-year National Health and Medical Research Council Early Career Fellowship.