First, you have to understand that the body ultimately uses three things for energy- glucose, fatty acids, and ketone bodies. Everyone talks about carbs, fat, and protein, but the body only uses glucose, fatty acids, and ketone bodies that are made from carbs, fat, and protein to run its functions. So, let’s take carbs out of the picture. This means no more glycogen (a bunch of glucose molecules linked together) for the body to use. What does the body do then? It starts to do two things- breakdown fat to fatty acids and break down protein to make glucose out of amino acids. This will provide the body with energy. These two processes are simultaneous. When the body breaks down protein to make glucose it doesn’t just take it from muscle, it takes it from all lean body tissue- all muscle AND organs like the liver, kidney, and heart. So, on a low carb high protein diet plan you actually stimulate your body and breakdown the organs that keep the body running. By the way, after 50% loss of lean body tissue, you die.
Second, your central nervous system is the most taxing on energy of all the other body systems. Usually your brain only uses glucose as an energy source. But in times of carbohydrate starvation it will resort to compounds called ketone bodies for energy. To make these compounds your body combines fat fragments. When ketone bodies build up in the blood it decreases the pH (makes it acidic) and this can create an imbalance in an otherwise normally stable system. Overly acidic blood can cause hyperventilation, lethargy, depression, and headaches. So much for looking vibrant and feeling energized.
In essence, while all these fad high protein diet menu plan options claim to help you become stronger, healthier, and have more energy, the sad truth is that most high protein diets that cut out the carbs do the exact opposite, and can be very harmful if used over a long period of time. Because of this, you need to make sure that if you do want to start a protein diet that you do not start one that eliminates carbohydrates from the menu.
So, before starting any high protein low carb diet plan, check with your physician to get his or her opinion. Another great outside personal resource would be a registered dietitian. This is not the same as a nutritionist (by way, that title is not recognized by any institution). A registered dietitian has a degree in the science of food and how you body uses it, and will spend time with you putting together a plan, both a diet and an exercise plan. Most likely your physician won’t spend the time to do this with you. Good luck!
UPDATE: For more information, including some good sources backing up this information, check out my other post: Ideal Protein Diet Review, part II.