High-protein diet for weight loss: scientific evidence, metabolic benefits, and implementation strategies

I. Definition of a High-Protein Diet A high-protein diet (HPD) is a dietary pattern in which daily protein intake exceeds 20% of total daily energy or 1.5g/kg body weight, but generally does not exceed 30% of total daily energy (or 2.0g/kg body weight). II. Implementation and Evidence of a High-Protein Diet 1. Evidence Studies have shown that obese individuals on a high-protein diet for 6 months experienced more significant weight loss than those on a moderate-protein diet. After a 1-year follow-up, the high-protein diet group still reduced abdominal fat by 10% more than the control group. A meta-analysis comparing high-protein, low-fat (HP) diets with standard protein, low-fat (SP) diets under energy restriction conditions with equivalent energy intake, in terms of weight loss, body composition, resting energy expenditure (REE), satiety and appetite, and cardiometabolic risk factors, found that high-protein diets were more effective in reducing body fat and also helped maintain energy expenditure. Another study assessing the effects of high-protein and high-carbohydrate diets on body composition, cardiovascular disease risk, nutritional status, bone turnover, and renal function in overweight women confirmed that obese individuals on a high-protein diet experienced greater weight loss (6.4 kg vs. 3.4 kg, P = 0.035) than those on a high-carbohydrate diet. In another study published in 2009, when subjects had a daily allowable energy intake of 20 kcal/kg, with protein comprising 30% of total energy, carbohydrates 45%, and fat 25%, and were supplemented with vitamins and potassium, they experienced a significant weight loss of (4.72 ± 4.09) kg after 12 weeks. BMI, waist circumference, and waist-to-hip ratio (WHR) also decreased by (1.87 ± 1.57) kg/m², (3.73 ± 2.91) cm, and (0.017 ± 0.029), respectively. In a study comparing energy-restricted high-protein, low-carbohydrate (PRO) and low-protein, high-carbohydrate (CHO) diets to examine compliance and long-term changes in body composition and blood lipids, healthy obese adults were randomly assigned to the PRO and CHO groups. After 4 months, although there was no significant difference in weight loss between the two groups, the PRO group showed a more significant reduction in body fat. Compared to the CHO group, the PRO group showed more significant improvements in serum triglycerides and high-density lipoprotein cholesterol, and had higher compliance. A two-year trial compared the weight loss effects of high-protein and high-carbohydrate diets in overweight individuals with diabetes, suggesting that a high-protein diet may be helpful for patients at risk of diabetes, cardiovascular disease, and metabolic syndrome. In a study of 113 moderately obese patients, after 4 weeks of very low-energy diet treatment, weight decreased by 5%–10%. Subsequent 6 months of weight maintenance using a high-protein diet (18%) and a normal-protein diet (15%) showed that the high-protein diet resulted in a lower rate of weight rebound. 2. Recommendations for high-protein diets (1) For those with simple obesity and those with hypertriglyceridemia or hypercholesterolemia, a high-protein diet is more beneficial than a normal protein diet for weight loss and improving blood lipid levels; and it is also beneficial for controlling weight rebound after weight loss. (2) Patients with chronic kidney disease should choose high-protein diets with caution.