This study compares the effects of two calorie-restricted diets-one with whey protein supplementation and one without-and a health education control group on weight and metabolic parameters in overweight and obese individuals, with the aim of informing dietary intervention strategies for this population.

The prevalence of overweight and obesity has been rising globally due to lifestyle and dietary changes. According to the "Report on the Status of Nutrition and Chronic Diseases among Chinese Residents (2020)", the proportion of overweight and obese adults in China has exceeded 50%. Overweight and obesity are not only major risk factors for chronic diseases such as diabetes and cardiovascular diseases but are also closely related to the increased risk of premature death. They have become one of the most serious public health problems.

Dietary intervention is a fundamental approach to the treatment of overweight and obesity. In recent years, the impact of different dietary structures on overweight and obesity has received increasing attention from researchers. The "Chinese Guidelines for Medical Nutrition Therapy of Overweight/Obesity (2021)" points out that a high-protein diet can reduce hunger, increase satiety, and increase resting energy expenditure, which is beneficial for weight loss and improving glucose homeostasis and blood lipid levels in overweight and obese patients. Studies have shown that increasing dairy intake during energy-restricted dietary intervention may help enhance satiety and reduce more body weight and fat mass. Whey protein is the protein component retained in the supernatant during the separation and precipitation of casein, and it is rich in essential amino acids. The proportion of branched-chain amino acids in its amino acid composition pattern is relatively high, which can promote the construction and repair of human tissue structure. Studies have shown that whey protein supplements can help overweight and obese patients lose weight and body fat, maintain lean body mass, and to some extent improve cardiovascular disease risk factors such as blood pressure and blood glucose levels. However, the potential mechanisms of action are not clear. In addition, the role of whey protein in the overweight and obese population in China remains to be studied. Based on this, this project designed two dietary models: a whey protein powder-supplemented energy-restricted high-protein diet and an energy-restricted balanced diet. They were compared with a health education control group to study the effects of whey protein powder on weight and metabolic indicators in overweight and obese patients, in order to provide a reference for dietary intervention in overweight and obese patients.

Inclusion Criteria:

• Age 25-35 years old, no gender restrictions
• Body mass index (BMI) ≥ 24 kg/m²
• Voluntary consent and signed informed consent form

Exclusion Criteria:

• Age < 25 years or > 35 years
• Current use of medications that may affect weight or energy balance (e.g., lipid-lowering drugs, antidiabetic drugs, appetite suppressants), or other protein supplements
• Presence of acute or chronic viral hepatitis, abnormal liver function (ALT or/and AST > 3 times the upper limit of normal), kidney disease (serum creatinine > upper limit of normal), diabetes, malignant tumors, or cardiovascular diseases
• Gastrointestinal disorders that affect food digestion and absorption (e.g., chronic diarrhea, constipation, severe gastrointestinal inflammation, active peptic ulcer disease, post-gastrointestinal surgery)
• Psychiatric disorders
• Allergies to product ingredients or presence of inborn metabolic disorders
• Pregnancy or lactation
• Other conditions deemed unsuitable for participation in the study by the researchers (e.g., severe diseases not listed in the exclusion criteria)