Longevity in Clinical Practice: What Really Matters When Metabolism and Lifestyle Interact

Blood Sugar as a Longevity Factor: Why Stability Matters More Than Perfection

1. Professor Kälicke, in a recent interview you spoke about practical everyday rules for improving blood sugar levels. Why do you believe blood sugar stability plays such a central role for energy, concentration, and long-term performance?

Prof. Dr. Kälicke: The human body functions best under stable conditions. This is especially true for our energy metabolism. When blood sugar fluctuates strongly, many people feel it immediately: energy drops, concentration declines, and people become tired or restless. A stable blood sugar curve, on the other hand, ensures that energy remains continuously available.

You can imagine it like an engine. An engine runs most efficiently when it operates steadily. If you constantly accelerate and brake abruptly, it becomes much less efficient. Our metabolism behaves in a similar way.

The good news is that achieving a more stable metabolic situation usually does not require complicated programs. Often, a few simple rules in everyday life are sufficient.

If metabolism has already become imbalanced—or to prevent that from happening—people can follow a simple seven-point plan:

1. Two to three meals per day instead of continuous eating
2. No snacking between meals
3. Close the kitchen about three hours before going to sleep
4. Move after eating—ideally for 10 to 20 minutes
5. Once or twice per week engage in intense activity and “get out of breath”
6. Incorporate one regular fasting day per week
7. Integrate movement as early in the day as possible

These rules are intentionally formulated to be practical. The goal is not perfection, but structure. Small habits implemented consistently can make a significant difference over the long term.

Side Fact: Blood Sugar & Metabolic Stability

Studies suggest that strong short-term fluctuations in blood glucose may be associated with increased oxidative stress and metabolic strain. More stable glycemic regulation is therefore considered an important factor for metabolic health.

Source: Monnier, L. et al. (2006). Activation of oxidative stress by acute glucose fluctuations compared with sustained chronic hyperglycemia. JAMA. Link: https://pubmed.ncbi.nlm.nih.gov/16609090/ 

Small Habits, Big Impact: What Clinical Practice Reveals

2. As a chief physician, you see daily how differently people manage their lifestyles. Which simple, realistic habits do you observe among people who manage to develop stable routines—especially regarding nutrition and metabolism?

Prof. Dr. Kälicke: Interestingly, it is rarely complicated strategies that work in the long term. People with stable routines usually follow just a few simple principles.

A clear meal structure plays an important role. Many people today eat almost continuously throughout the day. Those who instead plan two or three deliberate meals and give their metabolism rest in between often create a solid foundation.

Eating behavior itself is also important. Many people eat very quickly. However, our bodies need time to generate a satiety signal. Those who eat more slowly, chew thoroughly, and pause briefly after a portion often realize that less food is actually sufficient.

Another practical trick is surprisingly simple: smaller plates. They help many people better estimate portion sizes.

But the key point is something else entirely: consistency beats extremism. Those who try to do everything perfectly overnight often fail. Those who live by a few simple rules consistently usually have much better long-term success.

“The human body functions best under stable conditions. This is especially true for our energy metabolism. When blood sugar fluctuates significantly, many people feel it immediately: energy drops, concentration declines, and they become tired or restless.”

Longevity Without Extremes: Why Balance Is More Sustainable Than Trend Diets

3. Public discussions often focus on extreme diets or short-term programs. How do you see the relationship between scientific evidence and popular trends

Prof. Dr. Kälicke: Nutrition trends come and go. Sometimes carbohydrates are the focus, then fats, then completely new concepts.

What works long term is usually far less spectacular.

Scientific literature consistently shows that a diet consisting largely of unprocessed foods, sufficient protein, plenty of vegetables, moderate carbohydrates, and healthy fats provides a solid foundation.

Problems arise when nutrition becomes an ideological project. Extreme rules are often difficult to maintain in everyday life, which frequently leads people to give up entirely.

From my perspective, an approach is sustainable when it fulfills two criteria:

1. It is scientifically plausible
2. It works in everyday life

Healthy nutrition is not a short-term program—it is a lifestyle.

“However, the crucial point is a different one: consistency beats extremism. Those who try to do everything perfectly from one day to the next often fail.”

Muscle Health, Movement and Metabolic Flexibility

4. What role does regular physical activity play in the context of longevity—especially regarding the normal regulation of energy processes in the body?

Prof. Dr. Kälicke: Movement plays a central role in energy metabolism. Our muscles function as a major metabolic organ. The more muscle mass we have, the higher our basal metabolic rate. That means the body uses more energy even at rest. Physical activity also increases the performance metabolism—the additional energy we expend through movement.

This has practical consequences: people who move regularly often have greater metabolic flexibility and can consume more energy without immediately gaining weight. Furthermore, muscles release various signaling molecules during activity, known as myokines, which are involved in regulating numerous processes in the body—particularly anti-inflammatory processes.

Movement also supports the body’s ability to manage glucose. Muscle activity facilitates the uptake of sugar into cells and thereby contributes to the normal regulation of energy metabolism. From a longevity perspective, endurance training and strength training are not competitors—they complement each other perfectly.

Side Fact: Myokines – Why Exercise Influences Metabolism

During physical activity, muscles release signaling molecules known as myokines. These substances do not only act locally in muscle tissue but can also influence other organs such as fat tissue, the liver, or the immune system.

Studies suggest that regular exercise may contribute to the regulation of metabolic processes and inflammation-related mechanisms through these signaling pathways.

Source: Pedersen, B. K., & Febbraio, M. A. (2012). Muscles, exercise and obesity: skeletal muscle as a secretory organ. Nature Reviews Endocrinology. Link: https://www.nature.com/articles/nrendo.2012.49 

Micronutrients in Metabolism: Putting Them Into Perspective Rather Than Overestimating Them

5. Many people use vitamins or minerals as part of a longevity approach. In your view, how should micronutrients be understood when it comes to supporting normal functions

Prof. Dr. Kälicke: First of all, we should remember that micronutrients are primarily components of our food, not of dietary supplements. Vitamins, minerals, and trace elements naturally occur in many foods: vegetables, fruits, nuts, legumes, whole grains, fish, and high-quality animal products.

People who eat a balanced diet already cover a large part of their needs through ordinary foods. Dietary supplements can make sense in certain situations—for example, when an actual deficiency exists or when requirements cannot be sufficiently met through diet.

In this context, I strongly support the principle “measure instead of guess.”

If there is suspicion of insufficient supply, a laboratory analysis should be performed first. If a deficiency is identified, targeted action can be taken—ideally first through dietary adjustments and, if necessary, through appropriate supplements.

What I view critically, however, is the unreflective intake of numerous supplements according to the principle “more is better.”

“Sustainable change usually only occurs once a deeper understanding of the underlying mechanisms develops. Those who understand how nutrition, exercise, sleep, and metabolism are connected often develop a completely different motivation to maintain certain habits over the long term.”

Knowledge vs. Implementation: Why Good Intentions Often Fail

6. In your book “LNGVTY,” you discuss sustainable strategies. Why do many people struggle to change their behavior long-term despite having knowledge

Prof. Dr. Kälicke: We first need to distinguish between knowledge and understanding. Many people have a basic idea of what is generally healthy and what is not. However, this knowledge often remains superficial. Sustainable change usually occurs when people develop a deeper understanding of the underlying mechanisms. Those who understand how nutrition, movement, sleep, and metabolism interact often develop a very different motivation to maintain certain habits long term.

Another important point is how we formulate our goals. Many people say:  “I want to exercise more next year.” Such goals remain abstract. A change in identity is often more effective. When someone says:
“I am an athlete,” their behavior automatically changes. They create a training plan, prepare their sports bag the evening before, and organize their daily routine accordingly.

And finally, there is an important insight: between a stimulus and our reaction lies a moment of decision. In that moment, we can consciously ask ourselves: What would a health-conscious person do right now?

Long-term change therefore emerges from a combination of understanding, identification, and consistent small decisions in everyday life.

Side Fact: How Long It Takes to Form New Habits

New habits rarely emerge from a single burst of motivation, but rather from repeated actions in daily life.

Studies show that a new routine stabilizes on average after about 66 days of consistent repetition.

The actual duration strongly depends on the complexity of the behavior. Simple habits—such as drinking a glass of water after waking up—may become automatic after just a few weeks, whereas more complex behaviors like regular exercise often take longer.

Consistency matters far more than perfection.

Source: Lally, P. et al. (2010). How are habits formed: modelling habit formation in the real world.  European Journal of Social Psychology. Link: https://onlinelibrary.wiley.com/doi/10.1002/ejsp.674 

Longevity in Clinical Context: What Is Realistically Achievable

7. From a medical perspective, what are realistic goals when discussing longevity in terms of healthy years of life, functionality, and quality of life?

Prof. Dr. Kälicke: When we talk about longevity, we should first clearly define what we mean. Longevity does not mean stopping the aging process or becoming immortal. The goal is rather to push the healthy lifespan as far back as possible. 

Our genes play a role—but they are not everything. A significant portion of vitality in old age is influenced by lifestyle.

Five factors play a particularly important role:

• Nutrition
• Physical activity
• Sleep and recovery
• Stress management
• Social connections and a positive mindset

If these factors work together over many years, they can have a significant impact on functionality, vitality, and quality of life.

Ultimately, longevity means caring for the body in a way that allows us to remain active, independent, and capable for as long as possible.

Note: This interview is intended solely for general informational purposes. The assessments and statements presented reflect the personal scientific opinion and clinical experience of the interviewed expert and are based, among other things, on their own research.

The information shared reflects the expert’s personal professional experience and does not constitute official statements or claims by Vitamin Express.

The content does not constitute health claims authorized under EU Regulation (EC) No. 1924/2006 and should not be interpreted as statements regarding the prevention, treatment, or cure of diseases. This interview is not a substitute for individual medical advice. For health-related questions, please consult a healthcare professional.