Who is Prof. Dr. Peter Schwarz?
Peter Schwarz holds the Chair of Diabetes Prevention and Care at TU Dresden, where he heads the Department of Prevention at the Carl Gustav Carus University Hospital. In December 2022, he became the first German to be named President-Elect of the International Diabetes Federation was elected and assumed the presidency in December 2024. The IDF is the international umbrella organization for national diabetes associations, with approximately 240 member organizations in over 160 countries, representing some 589 million people with diabetes worldwide.
His research profile combines clinical internal medicine with health services research and diabetes prevention. His career includes a postdoctoral fellowship at the Howard Hughes Medical Institute at the University of Chicago, a postdoctoral qualification in internal medicine (2008), and an MBA in International Business. For Schwarz, the integration of medical science and healthcare systems is central to his work.
In addition to his academic work, Schwarz is publicly committed to three key issues that shape his agenda as IDF President:
- Global access to insulin. Schwarz regularly points out that in countries with weak healthcare systems, mortality rates among children and adolescents with type 1 diabetes are significantly higher because diagnosis, healthcare infrastructure, and access to insulin are often lacking. His proposal: an annual global diabetes survey, conducted and published each year on World Diabetes Day, so that patient organizations can use reliable data to build political pressure on their governments. The model is the international HIV movement, where comparable data transparency has contributed significantly to structural improvements in care.
- Digitalization in underserved regions. In large parts of sub-Saharan Africa and South Asia, diabetes care is sparse; the smartphone is often the only reliable link to patients. Schwarz is a co-founder of a diabetes app in Rwanda and refers to such applications as “digiceuticals.” According to him, Karachi, with a population of around 22 million, has only a single diabetes clinic, and there are about 120 diabetes counselors in all of Pakistan. Such gaps cannot be closed without digital tools.
- Prevention over treatment. His primary area of research remains the question of how type 2 diabetes can be prevented or reversed through lifestyle interventions: exercise, diet, weight loss, and supportive digital tools such as the fitness app “AnkerSteps.” He also views water fasting as part of this approach, seeing it as a short-term but intensive metabolic intervention.
The overarching principle of his work is: to treat type 2 diabetes not only with medication, but also to prevent it or bring it into remission whenever possible.
Water fasting: what happens in the body
During a water fast, the body goes without food for several days and consumes only water. During this time, the metabolism gradually switches to alternative energy sources. The time frames provided are approximate; they vary depending on metabolic state, physical activity, and prior diet.
- First 24 hours: Insulin levels and blood sugar drop, glucagon rises, and the liver mobilizes its glycogen stores. At the same time, gluconeogenesis begins.
- 24 to 48 hours: Glycogen stores are largely depleted. Fat oxidation increases significantly, the first measurable ketone bodies appear, and autophagy—the cellular “cleanup process”—becomes more important.
- After 48 to 72 hours: The body is in a state of deep ketosis. Ketone bodies become the primary source of energy for the brain, heart, and muscles; autophagy reaches its peak activity.
Schwarz associates this metabolic state primarily with a significant reduction in liver fat. In his view, reducing liver fat is a key strategy for combating type 2 diabetes, Insulin resistance and associated metabolic disorders. This hypothesis is supported by data on nonalcoholic fatty liver disease (NAFLD, increasingly referred to as MASLD in the scientific literature since 2023) as a major driver of insulin resistance.
Who is a good candidate for water fasting?
Schwarz primarily classifies water fasting as a strategy for people with type 2 diabetes, particularly those who have had the condition for a short time, are overweight, or have severe fatty liver disease. In these cases, an intensive metabolic intervention can reduce insulin requirements and, in some instances, contribute to remission.
The most scientifically well-documented reference for this approach is the DiRECT study. Intensive calorie restriction over 12 months led to diabetes remission in 46% of participants, defined as an HbA1c (long-term blood sugar level) below 6.5% without diabetes-specific medication[1]. After 24 months, the remission rate was still around 36%. Water fasting is not methodologically identical to the DiRECT protocol, but it follows the same basic principle: a severe, defined calorie deficit as a metabolic reset.
Type 1 diabetes: special caution is required
At Type 1 diabetes the risk profile is different. Without the body’s own insulin production and without a properly adjusted external insulin supply, the risk of diabetic ketoacidosis increases. In this context, fasting should not be viewed as a dietary measure, but rather as a medical intervention that must be supervised by a doctor.
Anyone with type 1 diabetes who is considering a fasting period should do so only after consulting a diabetes specialist. Basal insulin, CGM alerts, ketone monitoring, and a clear criteria for stopping the fast should be established before beginning.
The book by Prof. Schwarz
Schwarz outlined his approach in his 2026 book "Water Fasting – and How to Overcome Diabetes and Other Inflammatory Diseases in 14 Days" (DuMont Buchverlag) described in detail[3]. At the heart of the program is a two-week water-fasting regimen, which the author considers the most effective way to relieve metabolic stress.
We are providing a link to the book because it documents Schwarz’s professional position and gives interested readers access to the original concept. The book is published by DuMont Buchverlag and on Amazon available.
Frequently Asked Questions About Water Fasting for People with Diabetes
Can water fasting cure type 2 diabetes?
A blanket claim of a cure is not scientifically supported. However, there is robust evidence that intensive weight and metabolic interventions can lead to remission in type 2 diabetes. The DiRECT study showed a 46% remission rate after 12 months of the program[1]; after 24 months, the rate was still around 36%. Remission is defined as a normal HbA1c level without diabetes-specific medication. Relapses are possible, so ongoing monitoring remains necessary.
As someone with diabetes, should I try water fasting?
This decision should be made in consultation with a doctor. Fasting can be beneficial for people with type 2 diabetes. For those with type 1 diabetes, the risk of ketoacidosis is significantly higher, and medical supervision is essential.
Can I do a water fast while using an insulin pump?
Only with the supervision of a diabetes specialist. Basal rate, CGM alarm limits, and ketone levels must be adjusted in advance, and a termination criterion must be defined. Also, a nocturnal hypoglycemia can be dangerous while fasting.
What are ketone bodies?
Ketone bodies are metabolic products that the liver produces from fatty acids when glucose levels are low. Beta-hydroxybutyrate and acetoacetate are energetically significant; they serve as an alternative energy source for the body, particularly for the brain, heart, and skeletal muscles. Acetone is a byproduct of acetoacetate and is largely excreted in the breath, which explains the characteristic fruity breath odor associated with deep ketosis or ketoacidosis.
Is ketosis the same thing as ketoacidosis?
No. Diet- or fasting-induced ketosis is a controlled physiological state characterized by moderate ketone body levels and stable blood pH. Diabetic ketoacidosis, on the other hand, is a medical emergency characterized by severely elevated ketone body levels, a dropping blood pH, and a complete lack of insulin. This distinction is particularly critical in type 1 diabetes.
Note
This page is for informational purposes only and is not a substitute for medical advice, diagnosis, or treatment. Symptoms of severe hypoglycemia (confusion, seizures, loss of consciousness) constitute a medical emergency. Call emergency services (911) immediately and use prescribed glucagon. If you experience signs of diabetic ketoacidosis (strong acetone odor on your breath, nausea, abdominal pain, rapid, deep breathing), seek medical help immediately. Water fasting with diabetes, especially type 1 diabetes, should only be done under medical supervision. Hyporest is a dietary supplement, not a medicine.
