This is a summary of a preprint research study written by researchers primarily based at eidelberg (Germany) University Hospital on medRxiv provided to you by Medscape. This study has not yet been peer reviewed. The full text of the study can be found on

Key Takeaways

  • Patients with type 2 diabetes and protein in their urine who adhered to a fasting-mimicking diet for 5 consecutive days a month for periods of 3 or 6 consecutive months had significant reductions in urinary albumin-to-creatinine ratio (UACR) compared with patients on a control, nonfasting diet.

  • The fasting-mimicking diet also led to improvements in glucose, blood pressure control, body mass index (BMI), and a sustained reduction in insulin resistance when adjusted for weight loss.

  • This was a single-center, proof-of-concept study of 40 randomized patients who adhered to the study protocol for at least 3-monthly diet cycles.

  • The results also showed that monthly 5-day cycles of a fasting-mimicking diet can be integrated into clinical practice and are complementary to current guidelines for managing patients with type 2 diabetes.

  • This report is in preprint form and has not yet been peer reviewed.

Why This Matters

Study Design

  • Researchers at a single center in Germany randomized 40 patients (and one additional patient who almost immediately dropped out) with type 2 diabetes and microalbuminuria (33 patients) or macroalbuminuria (seven patients) to a fasting-mimicking diet (21 patients) or a control Mediterranean diet (19 patients) for 6 months.

  • Participants were instructed to comply for 5 consecutive days each month either with the fasting-mimicking diet (intervention group) or with a Mediterranean diet (control group) and to return to their normal diet until the next diet cycle that was initiated about 25 days later.

  • Thirty-eight participants completed three consecutive monthly cycles, 33 completed all six cycles of the study’s design, and 31 returned for a follow-up examination an average of 112 days after the end of the intervention phase.

  • The fasting-mimicking diet was plant-based and designed to mimic fasting-like effects on glucose and ketone bodies. Participants on day 1 consumed 4600 kJ (1095 calories) in the form of 11% protein, 46% fat, and 43% carbohydrates, and on days 2-5 they consumed 3000 kJ (714 calories) in the form of 9% protein, 44% fat, and 47% carbohydrate.

  • The Mediterranean diet allowed participants to consume their usual daily energy intake but adapted according to a Mediterranean Diet Score.

  • All patients in the study also received “intensive diabetes care.”

Key Results

  • After 3 months on treatment, 16 patients on the fasting-mimicking diet who had started with microalbuminuria had their average UACR fall from 43.7 mg/g at baseline to 29.1 mg/g, a significant 33% relative decrease after adjustment for age, sex, and weight loss. After 6 months, average achieved UACR was 23.4 mg/g in 14 assessed patients, a significant 46% adjusted relative decrease from baseline.

  • Among the participants randomized to the control, Mediterranean diet average UACR levels also declined from baseline after both 3 and 6 months on the intervention, but the reductions were not significant after adjustment.

  • The fasting-mimicking diet also resulted in other favorable results, including a significant reduction in average A1c from 8.1% at baseline to 6.7% after 6 months, and a significant reduction in average BMI from 31.0 kg/m2 at baseline to 27.7 kg/m2 after 6 months. Neither of these significant changes occurred among participants in the control arm.

  • The fasting-mimicking diet was well tolerated, with 71% to 95% of participants in this arm reporting no adverse effects (depending on the specific adverse event assessed) and with no participant on this diet reporting adverse effects of grade 3 or higher, including no reports of severe episodes of hypoglycemia or hypotension.


  • The control group received an isocaloric diet in contrast to the caloric restriction of the fasting-mimicking diet group. Weight loss in the fasting-mimicking diet group was higher and significant when compared to baseline and to the control group. To account for this, the researchers adjusted all statistical analyses of the study endpoints with a correction for weight loss.

  • The study had a small number of participants, which limits both the reliability of the results as well as their generalizability.

  • The study is limited in its ability to assess the impact of the intervention on renal cell metabolism, as the researchers did not obtain kidney biopsies.


  • The study received no commercial funding.

  • L-Nutra, a Los Angeles-based company, developed the fasting-mimicking diet and markets foods and other products designed to facilitate adherence to this diet. However, L-Nutra had no role in the design, funding, or conduct of the study nor in the data analysis and writing of the report.

  • One of the co-authors of the study is a founder and shareholder of L-Nutra. All of the other co-authors had no disclosures.

A six-month periodic fasting reduces microalbuminuria and improves metabolic control in patients with type 2 diabetes and diabetic nephropathy: a randomized controlled study.

Mitchel L. Zoler is a reporter for Medscape and MDedge based in the Philadelphia area. @mitchelzoler

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