Protein provides the necessary materials for the body to build and repair tissue, and produce hormones, among other vital functions. Most Americans get more than adequate amounts of protein in their diet, making deficiencies rare. Adult women should get 46 grams per day, adult men 56 g. You might think that if protein is so important, wouldn't more be better? Unfortunately, that is not the case. Excess protein consumption can have unexpected consequences.
The human body relies primarily on fat and carbohydrates for energy. With excessive protein intake, your diet might fall short of the recommended dietary consumption of these energy sources. Your body can break down proteins for fuel if needed, but it requires more energy and resources to do so, making it less efficient. A low-carb diet might impact your endurance so you cannot exercise as long.
The human body tends to respond conservatively to excess food intake by storing the excess so it has resources to turn to in times of stress. Excessive protein intake is no exception. However, extra protein is stored as fat that can lead to weight gain. Some people might follow a high-protein diet thinking that it might help them lose weight. In reality, this strategy might backfire if you do not keep total calorie intake in line with energy expenditure. Being overweight carries several serious health consequences, including an increased risk of heart disease and diabetes.
Digestion is a complicated process. Excess protein intake can impact it negatively, leading to lower bone density. A 2010 study by the Chinese Center for Disease Control and Prevention found that excessive protein intake, particularly from animal sources, decreased bone mass buildup in individuals with low calcium intake. Most disturbing about these findings is that the participants in the study were pubescent adolescents. Low bone mass density at this age sets the scenario for an increased risk of osteoporosis later in life. Even with adequate calcium intake, excess protein can increase calcium excretion, further complicating this risk.
Metabolic Rate Changes
A diet change to include higher protein intake can also affect your metabolic rate. The reason behind this phenomenon lies in the chemistry behind protein metabolism. The process requires more water, which can, in turn, lead to dehydration. Protein breakdown also increases the demand for oxygen. When you exercise vigorously, your body turns to carbs for energy because it is more efficient. The process requires oxygen. Excess protein consumption can deprive the body of the oxygen it needs to fuel activity, further impacting your athletic performance.
- Centers for Disease Control and Prevention: Protein
- "Nutrition for Health, Fitness and Sport"; Melvin Williams; 2004
- American Council on Exercise: Q -- Are There Any Risks Associated with Excess Protein Consumption?
- "British Journal of Nutrition"; "The Association Between Dietary Protein Intake and Bone Mass Accretion in Pubertal Girls with Low Calcium Intakes"; Q. Zhang et al; March 2010
- Colorado State University Extension: Nutrition for the Athlete