Intermittent fasting diet for weight loss: Evidence-based evidence and implementation guidelines for the 5+2 model

I. Definition of Intermittent Fasting Diet Intermittent fasting, also known as intermittent fasting, adopts a 5+2 pattern, meaning that for 5 days a week, patients eat relatively normally, and for the other 2 days (non-consecutive), they consume 1/4 of their usual energy intake (approximately 500 kcal/day for women and 600 kcal/day for men). II. Implementation and Evidence of Intermittent Fasting Diet 1. Evidence A study in the 1980s involving 519 outpatients undergoing 29.8 weeks of intermittent fasting treatment showed that 78% of patients lost more than 18.2 kg, with an overall average weight loss of 1.5 kg per week. Women averaged 1.3 kg per week, and men averaged 2.1 kg per week. Most patients tolerated the program without any serious side effects. A study based on 16 obese patients showed that after 8 weeks of alternate-day fasting intervention, patients experienced an average weight loss of (5.6±1.0) kg, an average waist circumference reduction of 4.0 cm, a decrease in body fat percentage from (45±2)% to (42±2)%, a decrease in systolic blood pressure from (124±5) mmHg to (116±3) mmHg, and a decrease in total cholesterol, LDL cholesterol, and triglyceride concentrations of (2±4)%, (25±10)%, and (32±6)%, respectively, while HDL cholesterol levels remained unchanged. A 2007 study also found that after 8 weeks of alternate-day fasting intervention, obese patients experienced an 8% decrease in BMI compared to baseline, while LDL cholesterol and triglycerides decreased by 10% and 40%, respectively. A 2013 study based on 115 obese women showed that after 3 months of intervention, obese patients using the two-day fasting method lost an average of 4 kg, while those using the traditional energy restriction method lost an average of 2.4 kg, with the former showing more significant improvement in insulin resistance. A 2014 meta-analysis on the prevention of type 2 diabetes found that intermittent fasting can effectively reduce weight and prevent type 2 diabetes, and improve blood glucose, insulin, and metabolic markers such as low-density lipoprotein cholesterol and high-density lipoprotein cholesterol in overweight and obese patients. 2. Recommendations for intermittent fasting (1) Intermittent fasting is beneficial for weight control and metabolic improvement. (2) While controlling weight, intermittent fasting may indirectly increase the benefits of weight control through improvements in metabolism and inflammatory response; at the same time, it enhances the treatment benefits of diabetes, cardiovascular and cerebrovascular diseases and other chronic diseases. 3. Development of intermittent fasting dietary plans Studies have shown that intermittent fasting has good safety, scientific validity, effectiveness and compliance in nutritional intervention for weight loss, and can change people's unreasonable eating habits and lifestyles. Suitable population: BMI>24kg/m²; overweight and obese people with excessive body fat percentage and waist circumference. Unsuitable population: children, thin people with BMI<18.5kg/m², patients with anorexia nervosa, patients with mental illness, patients with AIDS, patients with gastric ulcers, pregnant and lactating women, patients with nutritional deficiencies (such as iron deficiency anemia), patients with heart failure, patients with renal failure, and patients with liver diseases other than non-alcoholic fatty liver disease. (1) Timing of intermittent fasting: 7 days a week, of which 5 days are relatively normal eating, and 2 non-consecutive days are chosen for intermittent fasting. It is recommended to fast on Monday and Thursday, or you can choose Tuesday and Friday. (2) Method of intermittent fasting: On the 5 non-fasting days, the daily energy requirement can be obtained according to height and weight: standard weight (kg)×2025(kcal·kg⁻¹·d⁻¹). The energy supply ratio of the three macronutrients is 20% protein, 20% fat, and 60% carbohydrates. Dietary Requirements: Low-oil and light diet; no more than 15g of vegetable oil and no more than 6g of salt per day. The dietary plan remains relatively fixed for the two fasting days, with women consuming approximately 500kcal/day and men approximately 600kcal/day. Daily water intake should be 2000-2500ml. ◇Recommended for women's fasting days: 250ml skim milk or 100g yogurt, 1 egg, 150g fruit, 25g staple food, 250g vegetables, and 50g protein. ◇Recommended for men's fasting days: 250ml skim milk or 100g yogurt, 1 egg, 150g fruit, 50g staple food, 50g protein, and 250g vegetables. III. Precautions 1. Water: Daily water intake should be 2000-2500ml. 2. Choose fruits that are high in satiety, such as apples, grapefruits, papayas, blueberries, and citrus fruits; avoid fruits with high simple sugar content, such as durians and jackfruits; do not substitute dried fruit products for fresh fruit. 3. Choose cooking methods that use less oil and sugar, such as stir-frying, eating raw, or blanching. Avoid vegetables with high starch content, such as potatoes and corn.

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