New research from the American Society for Clinical Nutrition suggests that a high-protein diet not only helps in promoting better metabolism, it may also be the key to fighting worldwide obesity.
As the study reports, obesity has tripled worldwide in the past 45 years, where it now affects more than 650 million adults; moreover, the World Health Organization (WHO) has declared obesity as a global health emergency. Obesity is often associated with a higher risk of developing other illnesses, such as type-2 diabetes, cardiovascular disease and cancer.
In recent times, total diet replacements and nutritionally complete formulae foods, designed to replace the whole diet for a set period of time, have become increasingly popular strategies to combat obesity. High-protein diet, which has been shown to promote weight loss and weight maintenance by increasing one’s sense of fullness, energy expenditure and ability to maintain or increase fat-free mass, is also another popular weight management strategy.
Researchers believe that combining the overall effects of both these strategies, together, may be promising for weight management. There are several high-protein total diet replacement products widely available to consumers; but, until now, researchers have not been able to conclusively prove that they are effective weight management tools.
“Considering the prevalence of obesity worldwide and its impact on health, it’s not surprising nutritional strategies such as total diet replacement and high-protein diets are becoming increasingly popular as weight management strategies; however, research around these topics has not kept pace with their growth in popularity,” explains lead author on the study, Camila Oliveira, a doctoral student at the University of Alberta (Canada).
For the study, the researchers recruited a group of healthy, normal-weight adults between the ages of 18 years and 35 years using advertisements placed on notice boards at the University of Alberta. After a random selection, the participants were assigned into one of two groups. One group was fed the high-protein total diet replacement which consisted of 35% carbohydrate, 40% protein and 25% fat. While the other group, the control group, was fed a diet with the same number of calories, but consisting of 55% carbohydrate, 15% protein and 30% fat, a typical North American dietary pattern. The participants were given the prescribed diets for a 32-hour period while inside a metabolic chamber.
The findings of this in-patient metabolic balance study revealed that the high-protein total diet replacement led to "higher energy expenditure, increased fat oxidation, and negative fat balance," in comparison to the control diet. In particular, the results of the study provide further evidence that a calorie is not just a calorie. That is, a diet with a higher proportion of protein might lead to an increase in energy expenditure and fat oxidation compared to a diet consisting of the same number of calories, but with a lower proportion of protein as well as a higher proportion of carbohydrate or fat.
Dr Carla Prado, the study's principal investigator, commented that "although these results are restricted to a specific population of healthy, normal-weight adults, they can help nutrition scientists and healthcare providers better understand the real physiological effects of a high-protein total diet replacement in humans. In our opinion, it is imperative to first understand the physiological impact of a high-protein total diet replacement in a healthy population group so that the effects are better translated in individuals with obesity and its related comorbidities."
Researchers believe that the results of this study suggest high-protein total diet replacements may be a promising nutritional strategy for combat rising rates of obesity. But they also caution that future studies are needed to better understand the long-term effects of this type of dietary intervention, on the physiology of both, the healthy and the diseased, population groups.