Melbourne: Want to stay slim? Make sure that you eat enough protein in your diet, rather than simply cutting calories, says a new study.
Researchers at the University of Sydney have carried out the study and found that low protein in diets can lead to excessive energy intake and drive people to eat more snacks, the `PLoS ONE` journal reported.
On the contrary, they have found that enough protein in their diets help people in curbing appetites and preventing excessive eating of fats and carbohydrates.
The results represent the first scientifically supported evidence that dietary protein plays an important role in appetite and total food consumption in humans, and are an important step in addressing the global obesity epidemic.
"Humans have a particularly strong appetite for protein, and when the proportion of protein in the diet is low this appetite can drive excess energy intake.
"Our findings have considerable implications for body weight management in the current nutritional environment, where foods rich in fat and carbohydrates are cheap, palatable, and available to an extent unprecedented in our history," lead author Dr Alison Gosby said.
Protein is the driving force for appetite in many animals, according to the researchers.
Although it has previously been suggested that protein content plays an important role in determining overall energy intake in humans, and is therefore linked to obesity, until now experimental verification has been lacking.
In their study, the researchers wanted to test the `protein-leverage` effect in humans. So, they created three menus that represented low (10 percent), intermediate (15 percent) and high (25 percent) protein, based on data from the World Health Organisation recommending people eat 15 percent protein diets.
The researchers then took a group of 22 lean people and fed each subject each of the three menus during three separate four-day periods, monitoring energy intake over each four-day period and hunger ratings on day four.
They found subjects who ate a 10 percent protein diet consumed 12 per cent more energy over four days than those eating a 15 percent protein diet. Moreover, 70 percent of the increased energy intake on the lower protein diet was attributed to snacking.
When the protein content was further increased to 25 percent, however, the researchers observed no change in behaviour relative to the 15 percent protein diet. On the fourth day of the trial, however, there was a greater increase in the hunger score between one to two hours after the 10 per cent protein breakfast versus the 25 per cent protein breakfast.
Dr Gosby said: "This result confirms the protein-leverage effect in humans and importantly, shows counting calories is not enough to manage appetite and body weight."