Today, most individuals try various nutritional models/diets to reduce body weight. One of the most popular of these diets is the diets that reduce carbohydrate intake. Western societies generally avoid high carbohydrates and fat intake. For this reason, interest in high protein intake in diets is increasing day by day. Although there is no general consensus on what a high-protein diet is, the high protein diet (HPD) applied for weight loss studies is diets that contain approximately 30% of the energy provided by protein. The World Health Organization (WHO) has defined obesity as an endemic public problem and stated that its prevalence is increasing. With the increase in obesity, individuals try various dietary modifications to achieve weight loss. These include diets with a more regular macro and micronutrient pattern, such as the Mediterranean Diet and the DASH diet, and diets that may cause deficiencies in terms of macro and micronutrients, such as Atkins, South Beach, Zone, and Stillman, which contain high protein. The most important reasons why high-protein diets attract attention are that they cause rapid weight loss and provide satiety. This positive effect of HPDs on weight loss has attracted the attention of dietitians and caused them to increase the protein ratio in diets. Scientific authorities against popular diets; what is really known about popular diets, the scientific nature of the information, whether it is effective in maintaining body weight, if it is effective, its effect on body composition, micronutrient level, metabolic indicators, hunger-satiety, psychological state, chronic disease risk, its effect on leptin and insulin levels, which provide hormone regulation in long-term energy intake and expenditure.

It is known that HPDs provide more effective results in body weight loss compared to low protein diets. It is suggested that this effect occurs as a result of increased thermogenesis, increased satiety and suppressed appetite, and reduced glycemic index and glycemic load due to the replacement of refined carbohydrates with proteins. In addition to this positive effect on weight loss, there are possible short- and long-term side effects of HPD nutrition. Known complications of long-term HPD nutrition include increased cardiovascular disease risk, blood pressure, blood lipids, and kidney dysfunction. Cardiovascular problems in particular are a source of concern because they will counteract the short-term positive effect of HPD on weight loss and increase the burden of cardiovascular disease in the long term. Studies generally focus on HPD and weight loss; there is limited data on the relationship between HPD nutrition and metabolic dysfunction such as endothelial dysfunction, inflammatory markers, antioxidant status, and other chronic diseases. The physiological, biochemical, and molecular events that occur due to high protein diet nutrition have not been fully understood and their results have not been explained.

High protein diets (especially low carbohydrate diets) are thought to have negative effects because they cause a decrease in fruit and vegetable consumption. In those who eat a HPD, especially inadequate vitamin A, C and E in their diets, this will have a negative effect on antioxidant systems and will pave the way for the development of many chronic and metabolic diseases in the long term. Despite the positive effects of HPD applied as a weight loss diet in the short term, it is thought that the oxidative stress and inflammation it will create in the long term will cause an increase in chronic and metabolic diseases as well as comorbidities. This increase in the disease burden will increase health expenditures both individually and socially.

Therefore, this study was planned to provide information about the effect of short-term HPD feeding on early antioxidant response in adult, healthy, normal body mass index female individuals. As a result of the study, it is thought that short-term HPD feeding will cause an increase in oxidative stress, a decrease in antioxidant capacity and an increase in inflammatory biomarkers.