The Truth about High-Protein Diets

By Team Beachbody

There always seems to be some fad diet that's popular. For the last few years that honor has gone to the "high-protein diet," also known under many other names. Essentially, it's a diet where you eat a high percentage of protein and fat, and put enormous restrictions on your carbohydrate intake. It is believed that this will cause your body to use its stored body fat as fuel because it doesn't have carbohydrates, the body's preferred fuel source.

How it works: If you don't eat carbohydrates (these diets usually call for keeping consumption under 100 grams per day-about 1 bagel) your body will not produce high levels of insulin and if you eat a lot of protein you will produce more glucagon. With your body's glucagons/insulin levels in balance, your body's blood-sugar levels are more constant and-supposedly-your body will increase its use of stored fat as fuel. It is also said that high carbohydrate diets cause your insulin levels to increase, in turn storing excess carbohydrates as fat, instead of using them as fuel.

Does it work? Bodybuilders have proven the effectiveness that this type of diet can have on one's appearance. Deprived of carbohydrates for long enough, your body will start using its fat stores for fuel. If you do it for too long, or under improper guidance, then you will start to use (catabolize) your body's musculature as well.

Is it safe? In a word: no. At least, it's not safe according to the American Heart Association. You can certainly live like this for some time (the body is incredibly resilient), but cutting carbohydrates out of your diet and eating excess protein for long periods of time is extremely taxing on bodily functions. One effect of this diet is ketosis, the process by which your body uses its fat stores as fuel. When this happens your body naturally sheds a lot of water. This dehydration can cause brain damage, among other side effects, because your brain uses carbohydrates as a fuel source as well. Every gram of glycogen (complex carbohydrates) is stored with almost three grams of water, so you can see how cutting carbs out of your diet might also promote weight loss through dehydration. Also, excess protein is very hard to digest and many bodybuilders have suffered from kidney malfunctions that have been credited to high-protein/low-carb diets.

If you do it, a high-protein/low-carb diet should only be done for short periods of time, and even then, only under supervision or strict control. And, if your body fat is already fairly low, you will find that you have no good energy source and quickly run out of energy, making exercise and even simple physical functions seem taxing.

Why are people getting results? Many people—mainly women—are swearing by results they've achieved with a "high-protein diet". Increased energy is the most common virtue associated with this diet, something that for the above reasons can't be true for very long. The most common explanation that people see some result is that they are not eating enough protein in their regular diet and the increased protein is actually just bringing them up to normal. You should be getting about 30% of your daily caloric intake from protein and most people don't come anywhere close to that.

The other common scenario is that some people increase their protein intake and (unknowingly) don't severely reduce their carbohydrate intake—so they're actually just eating a more balanced diet. It's not uncommon to see a recreational bodybuilder extolling the virtues of his "no carb" diet over beers (100 grams of carb per beer!). It is very common for those on "high-protein" diets to be unaware of what are actually carbohydrates: for example all alcohol, fruits, and some vegetables. While thinking they are just eating protein, they are actually consuming carbohydrates too, and their body benefits by the balance of food sources.

The bottom line: Your body needs carbohydrates for energy, and needs a proper balance to operate in a healthy manner. However, the more you exercise, the more carbs you need. A healthy diet for a sedentary individual should consist of around 30% protein, 30% fat, and 40% carbohydrates. The more athletic you are, the higher your carbohydrate percentage should be. An ultra-marathoner may want to eat as much as 60 -70% carbs because so much of their performance is dependent upon high levels of glycogen and simple sugars.