Analysis of Urine Composition Saturation and Dietary Intervention in Subjects Without Urinary Calculi

\*Diet: Ordinary phosphorus diet: phosphorus content 1500mg High-phosphorus diet: Phosphorus content is 2500mg (inorganic phosphorus is added to the ordinary phosphorus diet) Low-phosphorus diet: Phosphorus content 500mg (The protein content and the ratio of plant protein and animal protein are consistent with the other two diets by adding egg protein and adding low-phosphorus whey protein powder. In addition, calcium magnesium tablets and potassium chloride salt are added to achieve the same calcium, magnesium and potassium content as others. The two diets are consistent) There are 2 recipes for each diet, and each recipe guarantees that the energy, protein, fat, carbohydrate, calcium, magnesium, sodium, potassium, oxalic acid content, vegetable protein and animal protein ratio are basically the same: Energy: 2100kcal (30kcal/kg, standard weight 70kg);Protein: 110g;Fat: 55-60g;Carbohydrate: 300g;Calcium: 600-700mg;Magnesium: 350-400mg;Sodium: 4600mg;Potassium: 2500mg Water:Giving subjects 2L of purified water without any minerals every day * Specimen We will collect 24h urine and feces for the whole day on the 2nd, 5th, 7th, and 10th days of the experiment, and collected morning blood and random urine on the 3rd, 6th, 8th, and 11th days. * Analysis We will use Equil 2 software to calculate the relative supersaturation of urine, and use SPSS software to analysis data