Here is the design of a clinical trial:

Official Title: Long-term Effects of the New Nordic Renal Diet on Phosphorus and Lipid Homeostasis in Patients With Chronic Kidney Disease, Stages 3 and 4 - A Randomized Controlled Trial

Included conditions:
- Chronic Kidney Disease(CKD)
- Hyperphosphatemia
- Blood Pressure

Study Armgroups:
- {'label': 'Intervention group, NNRD group', 'type': 'ACTIVE_COMPARATOR', 'description': 'Main principles of the interventional whole food approach are:\n\n* Maximum of 850 mg phosphorous/day\n* Protein: 0.8 g/kg/day\n* 80% vegetable products; 20% animal products\n* Maximum of 5-7 g NaCl/day (table salt)\n* Fresh raw products\n* Seasonal oriented\n* Fish: At least once a week\n* Vegetarian: At least once a week\n* Wide range of fruit and vegetables\n* Easy to follow in daily practice\n* Rich in flavors\n* Sufficient content of micro- and macronutrients', 'interventionNames': ['Other: Intervention group; NNRD group']}
- {'label': 'Control group', 'type': 'NO_INTERVENTION', 'description': 'There is no intervention, patients are following their habitual diet'}

Interventions:
- {'type': 'OTHER', 'name': 'Intervention group; NNRD group', 'description': 'The intervention is a whole food approach, meaning that the participants in the intervention group receives all daily food elements that they should consume', 'armGroupLabels': ['Intervention group, NNRD group']}

Primary Outcomes:
- {'measure': 'Difference in change in 24-hour urine phosphorus excretion from baseline to week 26 between the two study groups', 'description': '24-hour urine sample', 'timeFrame': 'Baseline, day: 14, 30, 60, 90, 120, 150, 180 and three months after study completion'}

Please estimate the sample size based on the assumption: 
Type-1 error risk of 0.05 (alpha, two-tailed), power of 80% (beta), SD of 24-hour urine phosphorus excretion of 200 mg, and a minimum clinically relevant difference of 300 mg.
Sample size calculation and statistical analysis
        The sample size calculation is based on results from previous studies performed by this study group. Within 6 months of participating in this study, we expect a decrease in eGFR to be about 1âmL/min/1.73 m2. This will have no influence on the total amount of 24-hour urine phosphorus excretion (primary endpoint), as CKD progresses and normophosphatemia is maintained by increasing the per nephron urinary phosphorus excretion stimulated by an increase in FGF23 and PTH leading to progressively increasing plasma levels of FGF23 and secondary hyperparathyroidism (SHP).
        In a randomised controlled study with a type-1 error risk of 0.05 (alpha, two tailed) and a power of 80% (beta) with an SD of 24-hour urine phosphorus excretion of 200âmg and a minimum clinical relevant difference of 300âmg, the study population is estimated at 21 in each group. There will be dropouts so we will include 30 participants in each group. The total number of participants to be included in this study is 60.