Grapes as most or all of the diet for weeks. Grape products modestly lower the upper blood-pressure number, improve insulin handling, and reduce excess weight; in lean, healthy adults that upside nears zero. The classical diet strips protein and fat, adds heavy potassium and sugar, has never been tested as a whole, and can displace effective cancer treatment. (Full Review)
| Marker | Target | Why |
|---|---|---|
| Potassium | 4.0–4.5 mmol/L | Grape intake adds grams of potassium daily |
| Estimated glomerular filtration rate (eGFR) | Above 90 mL/min/1.73 m² | Decides whether the potassium load is excreted or accumulates |
| Fasting glucose | 75–86 mg/dL | Tracks the sugar load most directly |
| Glycated hemoglobin (HbA1c) | 4.8–5.4% | Captures cumulative glucose exposure across a whole course |
| Uric acid | 3.5–5.5 mg/dL (men), 3.0–5.0 mg/dL (women) | Fructose raises urate production |
| Triglycerides | Below 80 mg/dL | Fructose drives liver fat synthesis |
| Albumin | 4.2–5.0 g/dL | Coarse marker of protein adequacy |
| Fat-free mass | No established target; track change from own baseline, a fall above 2% across a course is meaningful | The outcome most likely to be harmed by the regimen |
| Phosphate | 3.0–4.0 mg/dL | Falls sharply during refeeding |
| Magnesium (red blood cell) | 5.0–6.5 mg/dL | Shifts with phosphate during refeeding |
| High-sensitivity C-reactive protein (hs-CRP) | Below 0.5 mg/L | Baseline inflammation, on which pooled trials of grape polyphenols disagree |
| Home blood pressure | Below 120/80 mmHg | The one endpoint with pooled trial support |
Cadence: Full panel at baseline. During a course, potassium, creatinine and fasting glucose at day seven and at the end; blood pressure daily; phosphate and magnesium through the refeeding week. Four weeks after finishing, the full baseline panel and body-composition measurement are repeated, then every six to twelve months where courses recur annually.