Stewart · Postgraduate medical journal 1973 · case report · n=1

Features of a successful therapeutic fast of 382 days' duration.

Level 4 - case-series / case-control

Single case report

PubMed 4803438 · doi:10.1136/pgmj.49.569.203 · record verified 2026-08-26

What was done

A 27-year-old male underwent a supervised therapeutic fast lasting 382 days. Metabolic and endocrine responses were tracked through clinical follow-up as an outpatient, including glucose tolerance tests, tolbutamide tolerance tests, glucagon challenges, and serial measurements of plasma and urinary electrolytes.

What was found

Blood glucose concentrations remained around 30 mg/100 ml consistently across the final 8 months while the patient was ambulant. Glucose and tolbutamide tolerance test responses remained normal. The hyperglycaemic response to glucagon declined over time until it was absent, but normalized promptly upon carbohydrate refeeding. Plasma potassium remained normal without supplementation after an initial decrease was corrected. Plasma magnesium remained low from month 1 onward, and transient hypercalcemia appeared toward the end of the fast. After 100 days, urinary cation and inorganic phosphate excretion increased markedly and persistently. The patient experienced no ill-effects and maintained normal weight post-fast.

Why it matters

This report documents the human metabolic and physiological adaptations during an extreme, prolonged fast under clinical supervision.

Limits

This is an n=1 case report, precluding statistical inference or generalizability to other populations. Specific baseline weight, total weight lost, and precise numerical values for tolerance tests and electrolyte concentrations were not reported in the abstract.

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