What is the Difference Between 20g and 50g of Protein?

What is the difference between 50 and 20 grams of protein? The simple and obvious answer is 30 grams.
But Heather Leidy, assistant professor in the Department of Nutrition and Exercise Physiology at Missouri University has a much more detailed and interesting answer.
Her study, “Neural Responses to Visual Food Stimuli After a Normal vs. Higher Protein Breakfast in Breakfast-Skipping Teens: A Pilot fMRI Study”, published in Obesity in May 2011, measured brain activity in response to skipping breakfast, consuming 20 grams (3 oz.) or 50 grams (7 oz.) of protein.
When calories and fat were the same, eating more protein (7oz.), similar to a low carb eating plan, as compared to eating less protein, helped:
1. increase feelings of fullness throughout the day because hunger control signals in the brain were activated
2. lower “reward-driven” eating behavior
3. lessen the frequency of meals consumed (3 vs. 6 meals) because 3 meals were filling; eating more frequently with lower amounts of protein did not affect appetite or satiety
FYI: If you do not want to read the science, this press release sums it up nicely, http://www.eurekalert.org/pub_releases/2011-07/epr-hdc070811.php. They mention two other interesting studies:
1. “A study that showed men ate roughly 112 fewer calories at a buffet lunch and 400 fewer calories in the 24-hour period following a protein-rich egg breakfast compared to a bagel breakfast.”
2. “A study demonstrated that overweight dieters who ate eggs for breakfast lost 65 percent more weight and felt more energetic than those who ate a bagel breakfast of equal calories and volume.”
This is enough for me to suggest that anyone who has followed a calorie restricted diet and has felt deprived and hungry may want to consider adding a few ounces of protein to meals to stave off hunger and help control other aspects of eating behavior.