While protein is essential for muscle growth, and Soldiers or athletes trying to build muscle need more protein than others, diets that are too high in protein might not have room for enough carbohydrates that the body needs to perform at its peak.

Protein, fats and carbohydrates all provide energy for the body, but not in equal amounts. Protein almost never provides much energy ó only around 5 percent, even during intense training. Protein is more readily used to build body tissues such as muscle.

Fat, either from the diet or that our bodies store, serves as the main source of energy throughout the day and during periods of low-intensity exercise. This is beneficial because our bodies have enough fat stored to provide plenty of energy during times of low stress such as performing daily tasks ó walking or a slow jog. During times of higher stress, such as sprinting or weight training, carbohydrate serves as the main source of energy. However, our bodies store much less carbohydrates than fat, which is part of the reason why we cannot perform as long at high intensity as compared to low.

Our muscles produce the most energy when they have enough oxygen. When fats and carbohydrates are broken down for energy, the waste that is produced is carried away by oxygen. If too little oxygen is in our blood, waste products build up in our muscles, and they have a harder time producing energy. Therefore, the harder we work, the more waste we produce, and the more oxygen we need. This is why we continue to breathe heavier as the work gets harder until we must stop and ětake a breather.î

An exception to this process is that carbohydrates can still be used to produce small amounts of energy when no oxygen is available. Having enough carbohydrates available during intense physical activities (such as push-ups, sit-ups or fast running) allows energy to continue being produced when we are working hard and producing waste faster than we can breathe in oxygen. This allows us to delay the point when we can no longer produce energy and must stop ó which is referred to as the ěpoint of failure.î

Even though carbohydrates are the best source of quick energy and essential for energy during high-intensity exercise, the body only stores small amounts of carbohydrates in comparison to fat. Carbohydrates are stored in the liver and in the muscles. Muscular stores have the bigger impact on exercise performance when it comes to carbohydrates.

Eating enough carbohydrates each day helps us to pack our muscles with energy-producing carbohydrates that can help fuel those last agonizing seconds of our push-up, sit-up or two-mile run tests.

The benefit of good carbohydrate stores for physical performance has been studied for decades. A 1997 study showed that consuming a carbohydrate drink immediately before and during high-intensity cycling delayed the time it took for men and women to become exhausted and have to stop. Another study dating back to 1991 demonstrated greater work output in well trained cyclists who consumed carbohydrates before and during exercise.

The results from these studies and hundreds of others have led to the conclusion that carbohydrates can help improve physical performance. This opinion is also held by the American Dietetic Association, Dietitians of Canada, and the American College of Sports Medicine.

What it all means

What does all this mean to a Soldier or an athlete? Since our bodies can store only limited amounts of carbohydrates (much less than fat), it is important to have enough carbohydrates supplied by the diet in order to keep muscle stores filled. For trained athletes participating in general training (such as Soldiers who perform daily physical training for example) it is recommended they consume five to seven grams of carbohydrates for every kilogram (kg) of body weight (one kg is 2.2 lbs). Based on this range, a 165-pound (75kg) person should consume 375 to 525 grams of carbohydrate each day.

Protein needs are estimated to be much lower than those of carbohydrates. For trained athletes participating in general training, it is recommended they consume one or a little more grams of protein for every kg of bodyweight. Based on this range, a 165-pound person should consume 75 to 90 grams protein each day. Those who participate in additional, intense resistance training may benefit from slightly higher protein needs such as 1.2 to 1.5 grams per kg bodyweight.

Fat serves as a good source of energy, but fat intake should be based off of total calorie requirements and not body weight. It is recommended that 20 to 25 percent of total energy from the diet come from fat. These values show us that even the highest amounts of protein we should be getting are still much lower than what we need from carbohydrates in order to train at our highest level.

With all the low-carbohydrate diets and fitness magazines advertising high-protein intake, we commonly hear of recommendations for protein as high as two grams of protein per kg or higher.

Consuming adequate protein will help our bodies build muscle and recover from workouts, but too much protein will not cause any result in any extra muscle growth. In fact, diets that are too high in protein may not have enough in the diet for low-protein foods that supply carbohydrates, vitamins and minerals.

The added benefit of eating more carbohydrates and not over-eating protein is that foods high in carbohydrates usually cost less. We all know that high-protein foods can get expensive. For example, four boneless chicken breasts can cost around $5.50, one pound of lean ground beef can cost $5 to $6, and a bag of 100-count shrimp can cost up $7. These are some of the more expensive items found at a supermarket or commissary, but they are excellent sources of lean protein. Foods such as bread, rice and pasta are excellent sources of carbohydrates and can be found at much lower prices. A loaf of bread can range from $2 to $3, a box of spaghetti or penne pasta can be found for $2 or less, and a package of rice can provide two high-carbohydrate servings and cost around $1. By eating a little less meat, chicken or shrimp and eating more foods like rice or pasta we can save dollars at the store and get more out of our training at the same time.

So remember, Soldiers and athletes need to pay attention to what they eat and focus on more than just protein. Too eating too much protein is not only expensive, but it can prevent us from getting the most out of our training. Eating a balanced diet that is packed full of carbohydrates is the best way we can provide our bodies with the energy they need and help keep our pockets full of the money earn.