Despite the fact that short-term high protein diet could be necessary in several pathological conditions (malnutrition, sarcopenia, etc.), it is evident that “too much of a good thing” in diet could be useless or even harmful for healthy individuals.Many adults or even adolescents (especially athletes or body builders) self-prescribe protein supplements and overlook the risks of using them, mainly due to misguided beliefs in their performance-enhancing abilities. Individuals who follow these diets are therefore at risk.Extreme protein intake (in excess of 200 g per day), coupled with inadequate intake of other calorie sources (fat or carbohydrates), can cause a form of metabolic disturbance and death commonly known asrabbit starvation.
Extra protein is not used efficiently by the body and may impose a metabolic burden on the bones, kidneys, and liver. Moreover, high-protein/high-meat diets may also be associated with increased risk for coronary heart disease due to intakes of saturated fat and cholesterol or even cancer. Most high protein diets de-emphasize high carbohydrate! High fibre plant foods. These foods help lower cholesterol when eaten as part of a nutritionally adequate diet. This may consequently raise cholesterol and increase cardiovascular risk.
HOW DOES IT WORK?
These diets can cause a quick drop in weight because eliminating carbohydrates causes a loss of body fluids. Lowering carbohydrate intake also prevents the body from completely burning fat. In the diets that are also high in protein, substances called ketones are formed and released into the bloodstream, a condition called ketosis. It makes dieting easier because it lowers appetite and may cause nausea.Some high-protein, very-low-carbohydrate, weight-loss diets are designed to induce ketosis. When carbohydrate intake or utilization is insufficient to provide glucose to the cells that rely on it as an energy source, ketone bodies are formed from fatty acids. An increase in circulating ketones can disturb the body’s acid-base balance, causing metabolic acidosis. Evidence suggests that even mild acidosis can have potentially deleterious consequences over the long run, including low blood phosphate levels, resorption of calcium from bone, increased risk of osteoporosis, and an increased propensity to form kidney stones. These findings raise concerns that high-protein, high-fat, low-fiber, carbohydrate-restricted diets used for prolonged periods may increase the risk of health problems, despite the short-term weight loss that may accompany their use.
Diet which is high in protein generates a large amount of acid in body fluids. The kidneys respond to this dietary acid challenge with net acid excretion, and, concurrently, the skeleton supplies buffer by active resorption of bone resulting in excessive calcium loss.Moreover, acid loading directly inhibits renal calcium reabsorption leading to hypercalciuria in combination with the exorbitant bone loss.
Disorders of Renal Function
Low fluid intake and excessive intake of protein are important risk factors for kidney stones. Protein ingestion increases renal acid excretion, and acid loads, in turn, may be buffered in part by bone, which releases calcium to be excreted by the kidney. This protein-induced hypercalciuria could lead to the formation of calcium kidney stones. Furthermore, animal protein is also the major dietary source of purines, the precursors of uric acid. Excessive intake of animal protein is therefore associated with hyperuricosuria, a condition present in some uric acid stone formers.