Losing up to 10 lbs. within the first week of a diet, while eating as much as you want, may seem like every dieter’s paradise. The popular high-protein Dukan diet claims to help weight loss hopefuls achieve this and even help them keep the pounds off, but at what cost? According to a study published in the journal Nutrición Hospitalaria, high protein consumption increases the long-term risk of kidney disease and other renal diseases.

The consumption of a lot of protein, especially on the Dukan diet, can be dangerous for dieters in the long run because the reliance on pre-packaged products with extra protein can easily surpass a person’s daily protein needs. The recommended daily amount of protein for men is 56 grams a day, while for women it is usually 46 grams a day, an estimate that doesn't account for women pregnant or breastfeeding, according to the Centers for Disease Control and Prevention. Too much protein may contribute to severe kidney and liver problems, says Medline Plus, which can lead to further toxicity in the blood and more health impairments.

A team of Spanish researchers at the University of Granada, sought to examine the effects of a high-protein diet on plasma, urinary and morphological renal parameters in a group of rats. Twenty Wistar rats were randomly placed in two experimental groups with high-protein (HP) or normal-protein (NP) diets over the course of 12 weeks, which is the equivalent of nine years in human terms. The HP group was fed commercial hydrolyzed protein supplements with a 45 percent protein level.

The rats that were placed on the HP diet lost 10 percent of their body weight during the study, but no reduction was found in their cholesterol levels, or in the amount of fat in their blood, according to Science Daily. Moreover, urinary citrate, which prevents of crystallization of calcium salt, therefore preventing the formation of kidney stones, was 88 percent lower. The urinary pH was also found to be 15 percent more acidic. These findings reveal the rats were at a much higher risk of developing kidney stones.

The kidney is known to play a central role in protein metabolism. The amount and composition of proteins consumed have a direct impact on renal function, especially those with kidney disease. The study authors believe limiting the amount of protein consumed — particularly those from animal sources — is vital to slow the progression of chronic kidney disease and impaired renal function. The University of Maryland Medical Center says lifestyle factors, like eating specific foods, increase the risk of kidney stones, but more so in people who have a genetic or medical susceptibility. Diets high in animal protein and low in fiber and fluids are particularly at risk for stones. Approximately 80 percent of all kidney stones contain calcium and are usually combined with oxalate, or oxalate acid.

The high-protein, low-carb diet — based on a list of over 100 allowed foods — was devised by French nutritionist Dr. Pierre Dukan. Dieters can rapidly shed the pounds in a week by boosting their metabolism through the consumption of 68 protein-dense foods, according to Dukandiet.co.uk. This is known as the attack phase — the first of four phases of the diet. In phase two, the cruise phase, dieters must begin to eat protein-rich foods accompanied by the addition of 28 specific vegetables, for a total weight loss of 2 lbs. per week. The third phase, consolidation, aims to prevent any huge weight gain by reintroducing fruit, bread, cheese, and other starch-based foods into a normal diet with two meals a week. Lastly, the fourth and final phase, stabilization, dieters can eat whatever they want without putting on the pounds by having protein day once a week, eating oat bran every day and determined to “take the stairs.” This, supposedly, helps to prevent regaining the weight that they initially lost.

Followers of the Dukan diet, and other high-protein diets should be closely monitored due to the possible serious long-term side effects it may have on their health. In a study, published in the journal Applied Physiology, Nutrition, and Metabolism, scientists believe grape seed and skin extract (GSSE) could help in fighting kidney disease caused by high-fat diets. This may be of particular importance to Dukan dieters because this diet elevates plasma urea and protein in urine which may lead to the development of kidney disease. Therefore, the use of GSSE may serve as a preventative nutriceutical for people at high risk.

People who eat a balanced, whole-food diet, do not need to scramble to increase their protein intake. Healthy foods such as raw nuts and seeds, legumes and beans, broccoli, and even Romaine lettuce contain amounts of protein that will help meet the daily requirements and more.


Aparicio VA, Aranda P, Garcia-del Moral R, Machado-Vilchez M, Nebot E, Sanchez C. High-protein diets and renal status in rats. Nutr Hosp. 2013.

Aouani E, Charradi K, Elkahoui S, El May A, El May MV, Hamdaoui G, et al. Grape seed and skin extract alleviates high-fat diet-induced renal lipotoxicity and prevents copper depletion in rat. Applied Physiology, Nutrition, and Metabolism. 2013.