Does dietary protein suppress appetite?
I was saddened to hear the news earlier that the comedian, Mel Smith, has died of a heart attack aged just 60. I was also a little concerned at his passing as I am reckoned to be one of those in the high-risk category.
I watched an interesting documentary in the Horizon series concerning the Atkins Diet. It concluded with the suggestion that protein could actually be an appetite suppressant, which I find intriguing. Any chance that you might give your listeners a fuller explanation?
Chris Smith - Well, the answer is Tad, that what researchers in recent years have discovered is that there are populations of nerve cells in the brain which can sense the nutrients that you're eating. And here on the Naked Scientists just under 2 years ago, we had a researcher from Cambridge University called Dennis Burdakov who came in and he was describing a series of experiments where they have found a group of nerve cells in the bottom of the brain, a region called the hypothalamus and these nerve cells are called orexin nerve cells. They make you wake up. They also control what you want to eat. He has found that if you feed these cells with the same sorts of amino acids which are the building blocks of proteins, that someone would get from eating a protein-rich diet then these nerve cells dramatically alter their activity. Previously, we thought they only changed their activity in response to sugar levels, but it would clearly indicate from his work that they also change their activity on the basis of proteins as well. This therefore could be the basis of why, when someone eats a nice protein-rich breakfast, they then don't tend to feel as hungry through until say, lunchtime compared with people who are only fed a carbohydrate-rich breakfast because in experiments on groups of individuals who are doing similar sorts of jobs, similar sorts of metabolism, that's what you find. People who eat more protein feel less hungry through until their lunchtime compared with people who eat either no breakfast obviously or people who go for a carb-rich breakfast. So, if you want to stave off appetite, have a sausage for breakfast, but ideally, not one that's too fatty.