Protein digestion requires more energy to break down.

Eggs in bowl

Protein is the building block of our cells, enzymes, and muscle.  We would not exist without it.  It is one of three macronutrients that our bodies need to function.  We can make carbohydrates, bot the essential amino acids (the building blocks of proteins), must come from our diets.  For this reason, you should have a protein source at every meal.  Eggs are one example of a great source of protein.  

Eating protein has a lasting effect on your metabolism.  It can increase your metabolism for hours after the meal has ended.  Including as more protein in your diet will boost your metabolism. Protein requires more energy to digest than other macronutrients, and thus it increases your metabolism.  Also, protein promotes satiety.  Protein also has other weight loss properties such as promoting satiety after a meal is consumed.    The satiety and energy burning boost can last for hours.

The energy boost is called the thermic effect of food.  This boost is caused by the extra calories required to process the food before utilization.  There is an energy requirement for protein to be digested, absorbed, and processed after you consume them as a part of a meal.  Of the macronutrients (carbohydrates, fat, and protein), Protein causes the largest rise in the thermic effect of food.  One study estimates the increase in metabolic rate to be 15–30% for protein, compared to 5–10% for carbohydrates, and 0–3% for fats[1].  One small study looked at the effects of a 30% protein diet when compared to a lower 15% protein diet and found that people were likely to eat an average of 440 fewer calories per day[2].  To put this in perspective, 440 calories per day could result in one pound per week of additional weight loss just by increasing your protein consumption to 30% of your total daily calories.  

The bottom line: Protein can also help you eat less so eat plenty of protein and add it to every meal.  Eating more protein can increase your metabolism and result in more calories burned.    I personally try to consume approximately 35 to 40% of my calories from protein.  There are no harmful effects from increase protein diet is long as you do not have kidney disease.  Increasing protein consumption does not cause kidney disease as long as you are not predisposed to kidney disease.