Carbohydrates are bad.  Proteins are good.  This seems to be the common consensus that people have regarding these two substances.  The fact of the matter is that neither one is bad . There are good reasons, however, why protein appears to be more weight-loss friendly than carbohydrates.

First of all, it is important to note that protein and carbohydrate have the exact same caloric equivalent.  One gram of both carbohydrate and protein have the energy value of 4 calories. Since they both possess the same amount of calories you may wonder why carbohydrates would seem evil when compared to protein.  The answer lies in their digestion.

Carbohydrates are your body's favorite food.  70% of your diet should come from carbohydrate.  Carbohydrates are the equivalent of gasoline to your car.  Because carbs are your body's preferred fuel source, digestion is highly efficient and begins in the mouth.  Put a piece of candy in your mouth (most candy is pure carbohydrate), and it will dissolve.  This is because you have an enzyme in your mouth called amylase that will begin the breakdown of carbohydrate.  By the time carbohydrates arrive in your stomach, they are already partially digested.  Then, after a little time in the stomach, breakdown becomes complete and carbohydrate is ready for efficient digestion in your intestines.  Because of this system, carbohydrate digestion is almost 100% efficient.  In other words if you eat 100 calories of carbohydrate you'll probably digest 100 calories.

Protein digestion, on the other hand, is highly inefficient.  Whereas carbohydrate digestion began in your mouth, protein digestion does not begin until your stomach.  Put a piece of steak in your mouth and leave it there as long as you like.  It will look disgusting but it will not be broken down in the least.  When protein arrives in your stomach, breakdown begins.  The stomach breaks  protein down as best it can but if it does not break down the protein to a small enough molecule then protein absorption will be impossible in the small intestine. Protein digestion only occurs in the first five to six feet of intestine following expulsion from the stomach.  That means that if the stomach doesn't do a good enough job, the larger proteins that not been broken down will pass through the intestines and be expelled by the body.  Because of this system, protein digestion is only about 28% efficient.  That means that if you eat 100 calories of protein you will only digest about 28 calories.

Technically speaking, you can usually eat about three times as much protein as carbohydrate and digest about the same amount of calories.  While this might seem like a great idea, keep in mind that protein digestion is hard on the liver and kidneys.  Many people consume too much protein.  Protein should only be 10 to 15% of your diet or .8 grams per kilogram of body weight (you can figure out your body weight in kilograms by dividing your weight in pounds by 2.2)

The bottom line is that neither carbohydrates or proteins make you fat . It is simply the number of calories that you consume.  If you overeat you will gain weight whether the substance is all carbohydrate or all protein.  Remember, portion control is the key to losing or maintaining weight.