What exactly are proteins and why are they important?

Proteins are amino acids and have many different functions in the body. Our body uses about 20 amino acids to make proteins, nine of which must be obtained through food, making them essential. Animal products offer all nine essential amino acids and are thus termed, complete proteins. For example, a chicken breast offers all nine essential amino acids. Plant-based products offer some, but not all of the nine essential amino acids and are termed, incomplete proteins. For example, beans may only offer 5 of the 9 essential amino acids. So for vegetarians, it is important they eat a variety of plant products throughout the day to insure intake of all nine essential amino acids. Proteins function as enzymes, cell membrane receptors, carriers of nutrients in the blood, hormones, and play a role in immunity. Proteins are necessary for building, repairing, and maintaining all body tissues.

Most Americans get enough protein in their diet and some even exceed protein recommendations. Nutrients like protein, carbohydrate, and fat are called macro-nutrients and recommendations are distributed by percent of calorie intake. Recommendations for protein calorie distribution are as little as 10% to as high as 35% for adults. This means that on average, about 20% of your calories should come from protein.

If you eat 1500 calories: 1500 x .20 (20%) = 300 calories; 300 divided by 4 (calories per gram) = 75 grams of protein/day. Dietary Reference Intakes, set by the Food & Nutrition Board of the Institute of Medicine, do not recommend that people consume below 10% or above 35% of their calories from protein. Inadequate protein intake can weaken immunity and decrease energy levels. Many older adults do not consume enough protein-rich foods and this may contribute to declines in immunity and energy levels. Insure adequate protein intake by eating a variety of foods such as legumes (beans, lentils), fish, eggs, yogurt, cheese, soy, nuts, and meats. If we eat too much protein, it is either used for energy or stored as fat. If proteins are continually broken down and used for energy, they can’t be used to maintain body tissues and muscle mass. It is important for protein to be spared (not used as a major energy source) for muscle mass repair and maintenance, since muscle produces more energy than any other tissue in the body! Through muscle maintenance, we also help our body maintain a healthy metabolism.

Most experts agree that when it comes to overall fitness and muscle strength, athletic training is most important. Extra protein beyond what is generally recommended is either used as energy or stored as fat and offers no added benefits. Athletes often need more protein than non-athletes, mainly because they are using more energy and building more muscle or repairing muscle. Athletes that fall into this category include but are not limited to weight lifters, football players, and endurance athletes. It is especially important that teen athletes get adequate amounts of protein to insure proper growth and muscle building.

The high protein approach is currently popular for weight loss diets. Many people have successfully lost weight practicing high protein diets such as Atkins or South Beach. So what’s the secret? Calorie levels are often low on high protein diets and facts are, if you eat fewer calories than your body burns in one day, you will lose weight! Because these diets are so popular, research is currently evaluating moderate carbohydrate intake for weight loss and studying if moderate carbohydrate intake may be more appropriate for those with insulin resistance.

What are the current concerns with high protein diets?

That they may promote higher intakes of animal products such as red meat which can increase total and saturated fat, and cholesterol. Also, restricting fiber intake due to lack of whole grains, legumes, and fruits and may cause constipation.