Multidisciplinarity and health: why nutrition, movement, metabolism, and the environment must be understood as a single system

Contemporary medicine has achieved an extraordinary ability to study individual organs, molecules, and biological processes. But it is precisely specialization, when separated from the ability to integrate information, that can cause us to lose sight of a fundamental characteristic of physiology: the human organism does not function in independent compartments.

Metabolism is in continuous dialogue with the brain, adipose tissue with the immune system, muscle with carbohydrate metabolism, the gut with the nervous system, and the microbiota with immunity. Eating, movement, sleep, and stress simultaneously alter many of these pathways.

This is why a proper understanding of health requires a multidisciplinary perspective.

The founder of Naturocare's training arose precisely from the meeting of different fields: agricultural sciences, food, organism biology, physiology, and nutrition. Studying food from its origin means understanding not only what it contains when it reaches the plate, but also the relationship between soil, plant, microorganisms, cultivation, processing, and the organism that consumes it.

This perspective naturally leads to a broader question: what happens when food interacts with a living organism?

Not only how many calories it contains, but what signals it generates.

From calories to biological signals

A calorie is a physical measure of energy. From this point of view, a calorie is always a calorie.

Human physiology, however, is not a simple energy equation.

The same amount of energy introduced through different foods can be accompanied by different responses in terms of blood glucose, insulin, satiety, gut hormones, liver metabolism, microbiota, and eating behavior.

This does not mean that the energy balance does not matter: it matters a great deal. Rather, it means that the way the organism regulates the intake, use, storage, and consumption of energy is biologically complex.

A particularly interesting example comes from ultra-processed foods. In a randomized trial conducted at the National Institutes of Health, 20 adults followed an ultra-processed diet for two weeks and an unprocessed diet for two weeks, in alternating order. Although designed to be comparable in terms of calories provided and different nutrients, during the ultra-processed diet, participants spontaneously consumed about 500 kcal more per day and gained weight.

This finding is important because it concretely shows that the regulation of food intake cannot be interpreted solely through the number of calories present in the menu.

The quality, structure, palatability, and degree of processing of foods can alter eating behavior and therefore, indirectly, the energy balance.

The brain is not a simple calorie counter

Appetite regulation involves an extremely sophisticated network in which the hypothalamus plays a central role.

Information from adipose tissue, the gut, the pancreas, and the peripheral nervous system is integrated with signals related to energy availability, body composition, and the physiological state of the organism.

Leptin, insulin, GLP-1, PYY, ghrelin, and numerous other mediators participate in the regulation of hunger, satiety, and eating behavior.

It is therefore more accurate to speak of an energy regulation system than of simple calorie control.

This represents one of the scientific foundations of nutrition oriented toward biological signals: do not ignore energy, but understand how the organism perceives, uses, and distributes it.

Insulin is a metabolic regulator, not an enemy

Insulin represents one of the clearest examples of the need for a systemic view.

After a meal, the increase in nutrient availability stimulates hormonal responses that favor the use and storage of energy. This is an essential physiological process.

The problem arises when the metabolic environment becomes chronically characterized by energy excess, physical inactivity, sleep disturbances, high availability of ultra-processed foods, and overall reduced diet quality.

In this context, alterations in insulin sensitivity and the regulation of carbohydrate metabolism can develop.

For this reason, the goal should not simply be to “lower insulin,” but to promote a metabolic system in which insulin can normally perform its function.

In this case too, the need for multidisciplinarity emerges: eating, body composition, physical activity, sleep, and stress interact with each other.

Inflammation and metabolism: a bidirectional relationship

Adipose tissue is not just an energy store.

It is a true endocrine organ capable of producing adipokines and mediators that participate in the regulation of metabolism and immunity.

Adiponectin, leptin, and numerous other molecules contribute to communication between adipose tissue, muscle, liver, immune system, and brain.

Resistin has also been studied as a possible link between metabolism and inflammation, although its role in humans is much more complex than some simplified interpretations suggest.

The same applies to visfatin: it has been studied in relation to metabolism, inflammation, and adipose tissue, but it cannot be considered, on its own, the explanation for weight gain or metabolic disease.

Modern research therefore suggests a more cautious interpretation: low-grade chronic inflammation and metabolic dysfunction can mutually fuel each other through a network of mediators, rather than through a single molecule responsible for everything.

The microbiota further broadens the perspective

The gut represents one of the best examples of how necessary it is to overcome a linear view of health.

The gut microbiota interacts with food, produces metabolites, communicates with the intestinal barrier and the immune system, and can influence numerous physiological processes.

Dietary fiber represents one of the main tools through which the diet can support this relationship.

Legumes, whole grains, vegetables, fruit, nuts, and seeds provide substrates that can be used by the microbiota to produce metabolites, including short-chain fatty acids.

For this reason, a diet rich in plant-based foods should not be interpreted solely as a strategy to “eat less,” but as a way to modify the biological ecosystem in which digestion, metabolism, and immune response occur.

Epidemiological evidence is also significant: a meta-analysis of 25 prospective studies found an association between greater consumption of fiber and whole grains and a lower risk of colorectal cancer. For every increase of 10 g/day of total fiber, the relative risk was about 10% lower.

The World Health Organization now recommends a diet based mainly on minimally or unprocessed foods, with whole grains, legumes, fruit, and vegetables as important components of the diet and at least 25 g of natural dietary fiber per day in adults.

Eating well does not simply mean eating less

One of the most important consequences of this view is overcoming the opposition between quantity and quality.

An effective nutritional strategy must naturally consider the energy introduced and consumed, but also the quality of the foods.

The WHO recommends a varied diet, with a wide presence of fruit, vegetables, legumes, and whole grains, limiting free sugars, saturated fats, trans fats, and highly processed foods.

This approach does not necessarily require demonizing entire food categories. Rather, it requires shifting the focus of eating toward whole, nutrient-dense, and fiber-rich foods, leaving ultra-processed foods a marginal role.

The quality of the diet therefore becomes part of metabolic regulation.

The Mediterranean diet as an example of a systemic approach

Clinical research on the Mediterranean diet represents a particularly interesting example.

In PREDIMED, a multicenter randomized study on people at high cardiovascular risk, a Mediterranean diet enriched with extra virgin olive oil or nuts was associated with a reduction in major cardiovascular events compared to the control group. The results were subsequently reanalyzed and republished after the identification of irregularities in the randomization procedures of the original study.

Furthermore, PREDIMED analyses highlighted the favorable effects of the Mediterranean diet on some inflammatory markers.

The interesting point, however, is not the individual food.

It is the overall pattern: vegetables, fruit, legumes, grains, extra virgin olive oil, nuts, fish, and a reduced presence of processed meats and sweets.

This is the systemic logic: the biological effect of a diet is not necessarily the simple sum of the isolated effects of its individual ingredients.

Movement is a biological signal

The same philosophy can be applied to physical activity.

Reducing movement to a simple way to “burn calories” means losing an essential part of its biological function.

Skeletal muscle is an endocrine organ. During physical activity, it produces and releases numerous myokines, molecules involved in communication between muscle, adipose tissue, liver, immune system, and other organs.

The studied mechanisms include intracellular pathways such as AMPK, PGC-1α, and SIRT1, associated with modifications of mitochondrial function, fatty acid oxidation, and metabolic adaptation.

Irisin is one of the most studied myokines in the relationship between exercise and metabolism, although its physiology in humans and its real clinical weight are still under research.

So movement does not simply communicate:

“It consumes energy.”

It also communicates:

“Adapt your organism to be more efficient.”

This is one of the reasons why physical activity can improve cardiometabolic health, muscle function, bone health, mood, and sleep quality independently of the simple effect on body weight. The WHO recommends for adults at least 150–300 minutes per week of moderate aerobic activity, or 75–150 minutes of vigorous activity, associated with muscle strengthening activity at least two days a week.

Sedentary behavior is a signal, not simply an absence of exercise

The absence of movement also produces biological consequences.

When muscle is used less, the stimuli necessary to maintain mass, oxidative capacity, and metabolic flexibility decrease.

The communication between muscle and adipose tissue changes, and insulin sensitivity, lipid metabolism, and inflammatory response can be altered.

Sedentary behavior, therefore, should not be considered simply as “not doing sports.”

It is a biological condition in which some fundamental physiological signals are missing.

Sleep and stress are part of the same network

A truly multidisciplinary view cannot stop at nutrition.

Insufficient sleep, chronic stress, circadian rhythm disturbances, and sedentary behavior can alter eating behavior and metabolic regulation.

The nervous, endocrine, and immune systems communicate continuously.

For this reason, eating slowly, dedicating time to the meal, sleeping adequately, and reducing stress are not simple common-sense tips separate from physiology.

They are interventions on the same regulation system.

The thyroid shows why physiology must be read as a network

Thyroid physiology represents another example of the need for an integrated reading.

The hypothalamus-pituitary-thyroid axis regulates the production of thyroid hormones, which influence energy expenditure, thermogenesis, cardiovascular function, metabolism, and the activity of numerous tissues.

Thyroid hormones also act at the mitochondrial level and participate in the regulation of energy production and consumption.

But this does not mean that a metabolic slowdown can be solved simply by “stimulating the hypothalamus” through diet.

In the presence of a true thyroid pathology, diagnosis and medical treatment remain fundamental.

The most important lesson is another: the function of an organ cannot be interpreted in isolation from the endocrine and metabolic system in which it is embedded.

The true meaning of signaling medicine

The concept of “signaling medicine” can be useful if understood as an interpretive model: observing biological signals and understanding how diet, physical activity, sleep, stress, environment, and body composition contribute to modifying them.

It does not mean replacing conventional medicine.

It does not mean unilaterally discontinuing pharmacological treatment.

And above all, it does not mean attributing therapeutic properties to a food or molecule that clinical research has not demonstrated.

Rather, it means using knowledge of biochemistry, physiology, endocrinology, nutrition, and internal medicine to build coherent and personalized interventions.

This is where multidisciplinarity becomes truly operational.

From agriculture to physiology: a circular vision

The distinctive element of an education that starts with agricultural sciences is precisely the possibility of observing health through a broader chain:

SOIL → PLANT → FOOD → MICROBIOTA → METABOLISM → ORGANS → ORGANISM

Each step influences the next.

The quality of the food depends on its origin and its processing; the composition of the food influences the microbiota and metabolism; metabolism communicates with the endocrine and immune systems; these systems interact with the brain and behavior.

Health therefore becomes a circular and dynamic phenomenon, not a linear sequence of cause and effect.

A new idea of nutrition

The goal of biomolecular nutrition, in its most scientifically prudent interpretation, should not be to impose a universal menu.

It should be to teach how to recognize the quality of foods and the way in which their consumption fits into individual metabolism.

A health-oriented dietary model can prioritize:

vegetables and fruit, legumes, whole grains, nuts and seeds, extra virgin olive oil, adequate sources of protein, minimally processed foods, and a sufficient amount of fiber, reducing free sugars, ultra-processed foods, trans fats, and excessive consumption of salt and saturated fats.

Quantity remains important, but it cannot be separated from quality.

And it is precisely the quality of the diet, together with physical activity and other lifestyle behaviors, that can make the spontaneous regulation of appetite and metabolism more favorable.

Weight loss as a consequence, not as the sole goal

In this perspective, weight loss is not necessarily the starting point.

Rather, it is one of the possible results of an overall improvement in lifestyle.

When the quality of the diet and physical activity increase, body composition, metabolic capacity, and appetite management improve, weight may change as a consequence of these changes.

But health and weight are not synonyms.

A person can have a normal weight but poor metabolic health; similarly, an overweight person can improve insulin sensitivity, cardiorespiratory capacity, muscle strength, and cardiometabolic markers even before seeing a major change on the scale.

This is an important cultural shift: metabolic health cannot be reduced to the number displayed on the scale.

The role of the multidisciplinary professional

In this model, the figure of a professional capable of engaging with multiple disciplines emerges.

Not necessarily someone who replaces different specialists, but someone capable of integrating information.

Nutrition, movement, metabolism, sleep, stress, microbiota, and body composition must be able to be interpreted within the same framework, while maintaining clear boundaries between lifestyle education and medical treatment.

Multidisciplinarity therefore does not mean doing everything.

It means knowing when to integrate different expertise.

It is this integration that allows the transition from simply prescribing a behavior to understanding why that behavior can modify a specific physiological process.

Health as a system

The true revolution therefore does not consist in replacing the word “calorie” with the word “molecule.”

It consists in understanding that energy, nutrients, hormones, the nervous system, microbiota, muscle, adipose tissue, immunity, and the environment are all part of the same biological system.

Diet is a signal.

Movement is a signal.

Sleep is a signal.

Stress is a signal.

The quality of the environment and foods also represents part of the information to which the organism must adapt.

The mission of a multidisciplinary approach to health is precisely this: to bring the complexity of physiology into everyday life, transforming scientific knowledge into behaviors that are understandable, sustainable, and consistent with human biology.

Not a diet to follow for a few weeks.

Not an endless list of prohibitions.

Not the search for a single miracle molecule.

But a system in which diet, movement, recovery, psychological balance, and the environment once again interact with each other.

And this is probably the most interesting direction of contemporary preventive medicine and nutrition: not to continuously fight an isolated symptom, but to understand the biological networks that keep the organism in balance and to create, day after day, the conditions for that balance to be sustained.

Essential bibliographic references

1. Hall KD, Ayuketah A, Brychta R, et al. Ultra-Processed Diets Cause Excess Calorie Intake and Weight Gain: An Inpatient Randomized Controlled Trial of Ad Libitum Food Intake. Cell Metabolism. 2019;30(1):67-77.e3.
2. Estruch R, Ros E, Salas-Salvadó J, et al. Primary Prevention of Cardiovascular Disease with a Mediterranean Diet Supplemented with Extra-Virgin Olive Oil or Nuts. N Engl J Med. 2018;378:e34.
3. Casas R, Sacanella E, Estruch R. The immune protective effect of the Mediterranean diet. Mediterranean Journal of Nutrition and Metabolism. 2014.
4. Aune D, Keum N, Giovannucci E, et al. Dietary fibre, whole grains, and risk of colorectal cancer: systematic review and dose-response meta-analysis of prospective studies. BMJ. 2011;343:d6617.
5. World Health Organization. Healthy diet. WHO recommendations on dietary patterns, free sugars, fats, fruit, vegetables, pulses and whole grains.
6. World Health Organization. Physical activity. Recommendations and evidence concerning cardiometabolic, musculoskeletal and mental-health benefits of regular physical activity.
7. Chen N, Li Q, Liu J, Jia S. Irisin, an exercise-induced myokine as a metabolic regulator: an updated narrative review. Diabetes Metab Res Rev. 2016;32(1):51-59.
8. Exercise-Induced Muscle-Fat Crosstalk: Molecular Mediators and Their Pharmacological Modulation for the Maintenance of Metabolic Flexibility in Aging. Review of myokines, adipokines, AMPK, PGC-1α, SIRT1 and metabolic adaptation.