Interview Fasting for Health: When Metabolism and Internal Clock are aligned

“Fasting has a variety of metabolic benefits. Time restricted eating like it is supposed in intermittent fasting aligns the metabolism with our internal clock and for that improves our metabolic health.”

_{Prof. Stephan Herzig, Research Director at Helmholtz Munich, Director and Department Head of the Helmholtz Diabetes Center and Director of the Institute for Diabetes and Cancer.}

Prof. Stephan Herzig research focuses on common diseases such as obesity and diabetes and their long-term complications, including cancer. Herzig uses insights from fasting metabolism to identify novel therapeutic targets for treating metabolic dysfunction.

SH: Fasting has become popular, and this is based on a number of clinical and preclinical studies demonstrating a whole variety of metabolic benefits. They include changes in body weight, improvements in blood pressure and glucose control, and also improvements in lipid metabolism. There are many different forms of fasting: intermittent fasting, periodic fasting, alternate day fasting…
We think, it's in particular interesting to consider time restricted eating because many of our metabolic processes in our body are controlled by our internal clock – and the restriction of food intake to a certain time of day actually aligns the metabolism again with our internal clock.

SH: In shift workers we can see the risks when our internal clock is not well alignment with the metabolism: These people can have a high risk for the development of metabolic complications, including obesity and diabetes. So, any alignment of our internal clock with metabolism and food intake is beneficial for metabolic health.

SH: We know from clinical and also preclinical studies that intermittent fasting or any protocol that relates to voluntary food restriction, improves a number of metabolic properties: For example, improvements in the glucose control of the beta cells, meaning that our body secretes less insulin. Therefore, the lipid homeostasis and within the cell autophagy is improved. This process that leads to the degradation of unwanted products and molecules is actually turned on by intermittent fasting.

SH: Since intermittent fasting has many effects on our body, on our metabolism in general it can also affect many disease areas: An improvement in metabolic control through intermittent fasting can help to prevent obesity, diabetes and cardiovascular risk. It even can prevent the development of tumors as we know they are long term complications of diabetes.

SH: The environment at Helmholtz Munich helps us to understand the variety of benefits that are achieved through intermittent fasting: Here we have experts focusing on all these different disease areas and who collaborate in a network. We even include artificial intelligence to understand at the molecular level what single cells do and how single cells respond to excess food.

SH: There are a number of clinical studies in both type one and Type two diabetes patients employing fasting regimens, and it has been shown that intermittent fasting can indeed help to decrease glucose levels and also decrease the need for diabetes medications. However, it is also clear that more long-term studies in humans in particular are necessary to really evaluate the long term benefits, meaning long term benefits beyond one or two years of intermittent fasting. In any case, patients affected with diabetes should always do intermittent fasting in close consultation with their doctor, because in some cases there might be the chance for hypoglycemic events. And this is of course something one needs to avoid under any circumstances.

Our own current research addresses two main tracks: On the one hand, we have employed clinical studies using intermittent fasting in patients with diabetes and we have been able to demonstrate that indeed intermittent fasting can improve kidney function in patients with nephropathy. At the more preclinical level, we currently try to understand what the molecular and biochemical differences between different fasting regimens are. From our molecular knowledge, we want then to derive new fasting mimicking therapies.

SH: A main milestone in recent diabetes research has been achieved by the finding that diabetes does not only consist of just type one and type two diabetes, but there are at least five or six different subtypes of diabetes. All these subtypes are different in terms of their metabolic properties, and they probably also need to be treated in very different ways.

SH: Our research is always now geared towards these different subcategories of diabetes, trying to understand whether and how, for example, intermittent fasting or fasting based therapies can be a benefit or even no harm to these different sub phenotypes of diabetes and thereby then have tailored approaches for individual patients.

Latest update: April 2024.