If you've ever noticed that you stay full longer with the addition of a hard-boiled egg or some low-fat yogurt at mealtime, this may be because protein boosts the level of a "satiety hormone" known as peptide YY (PYY).

Researchers have found in the past that both obese and normal-weight people given injections of PYY reduce their intake of food significantly. Now a new report in the journal Cell Metabolism suggests that protein has this effect on the appetite because it stimulates the body's own production of PYY, leaving people feeling full for a longer time after eating.

Current Western diets are comprised of about 49% of calories consumed from carbohydrates, 35% from fat, and 16% from protein. Some scientists contend that people in earlier civilizations ate as much as twice this amount of protein.

More study is needed before there will be any recommendation for increased protein in our diets. And even a higher amount is recommended, it will not include proteins that are high in saturated fat.