High-protein diets pose certain health risks. Long term, these diets increase your risk of diseases, such as coronary heart disease and diabetes. Incidence of high cholesterol and low fiber from such diets affects several systems within your body. For example, high amounts of protein's break down products cause excessive strain on your kidneys within the urinary system and low fiber increases your chances of colon cancer. Despite accompanying weight loss, diets high in protein increase the incidence of health problems.
Protein Defined
Protein is an essential nutrient your body uses to create new and replacement body tissues. Children require more protein because they grow tissues at faster rates than adults. Dietary proteins exist as meat protein, dairy protein or vegetable protein. Fish and soy proteins benefit your body by assisting it with lowering blood cholesterol, while meat and dairy proteins often have high levels of saturated fats. Diets high in saturated fats contribute to higher rates of heart disease.
Amounts of Dietary Protein
Americans eat about twice as much protein as they need. According to the American Heart Association, only 10 to 12 percent of total consumed calories should be from protein. The actual grams protein your body needs is calculated by multiplying your ideal weight by 0.36. Those following high-protein diets consume up to 34 percent of their total calories as protein and 53 percent as fat. A typical hamburger contains 22 g of protein and 20 g of fat. That one hamburger is one-third of an adult's daily protein requirement.
Heart Disease
High-protein diets tend to be high in saturated fats. Diets high in saturated fats may raise your blood cholesterol to unhealthy levels. High cholesterol levels cause clogged arteries, which lead to heart attack and stroke. Long-term high-protein diets may increase your risk of heart disease by 50 percent. Secondary to high fat, high-protein diets tend to be low in fiber. Therefore, fiber's innate ability to lower blood cholesterol levels is deficient as well. During a high-protein diet, the high-fat and low-fiber ratios provide you with two ways to increase your risk of heart disease.
Ketosis
High-protein diets promote ketosis. Ketosis happens when body fat releases fatty acids, which partially metabolize into products called ketones. It is usually seen during starvation, but can occur during high-protein diets as well. Extended ketosis can develop into ketoacidosis and become life-threatening. A healthy body does not resort to ketosis during normal metabolism. A July 2001 article in "The American Journal of Cardiology" notes that ketogenic diets had impaired mental processing and flexibility in patients during a 1995 study.
Renal Implications
If you have diabetes or existing kidney disease, high dietary protein levels may increase your risk of kidney damage. Renal function is estimated by how much blood your kidney can filter in a minute by looking at a waste product called creatinine. As levels of creatinine increase, kidney filtration decreases. In high-protein diets, your body uses extra water to flush large amounts of protein byproducts through the kidneys. As the water increases, the filtration rate compensates, making the kidney work extra hard. Therefore, high-protein diets may hasten renal failure in those with kidney disease.
Other Complications
When kidneys compensate for high protein in the diet with an increased filtration rate, the body loses minerals in the urine. Calcium loss increases incrementally with increases in dietary protein. This loss contributes to kidney stone formation and osteoporosis. As the composition of the urine changes, calcium becomes insoluble and clumps together to form stones, which create painful blockages. Additionally, calcium stored in bone is mobilized due to the low blood calcium levels. The lost calcium causes the fragile bones of osteoporosis.
References
- Johns Hopkins Medicine: The Dangers of High-Protein, Low-Carbohydrate Diets for People With Diabetes
- CBS News; A Warning to Atkins Dieters; Rome Neal; November 2003
- Feminist Women's Health Center; High-Protein Diets -- Are You Losing More Than Weight?; Monique N. Gilbert
- American Heart Association: High-Protein Diets
- "The American Journal of Cardiology"; Metabolic Effects of High-Protein, Low-Carbohydrate Diets; Margo A. Denke; July 2001
- National Kidney and Urologic Diseases Information Clearinghouse; Kidney Diseases of Diabetes; September 2008
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