Nutrition Diet: How do scientists define food?

October 24, 2025 •

4 min read

The scientific definition of food is more complex and multi-faceted than commonly believed, extending beyond a simple provision of energy to encompass its nutritional, structural, and cultural roles. While we eat food, nutrition is the physiological process that follows ingestion, illustrating a key distinction understood by scientists.

Quick Summary

Scientists define food as any edible substance providing energy and nutrients for growth and maintenance, considering its complex matrix and interaction with the body. This definition also accounts for its cultural context and processing level, distinguishing it from isolated nutrients.

Key Points

Beyond Basic Nutrients: Scientific definitions of food extend beyond carbohydrates, fats, and proteins to include essential vitamins, minerals, and the complex interaction of these components in the 'food matrix'.
Food vs. Nutrition: Food is the substance consumed, while nutrition is the biological process of assimilation and utilization. Scientists stress the importance of eating whole foods, not just isolated nutrients.
The Food Matrix: This concept explains how a food's complex structure and composition influence how the body digests and absorbs nutrients, a concept often called 'food synergy'.
Processing Matters: The NOVA classification system categorizes foods into four groups based on their level of processing, linking highly processed foods to negative health outcomes.
Cultural and Social Context: The scientific perspective acknowledges that food's definition is also shaped by cultural norms, personal preferences, and psychological factors, not just its physiological effects.
Functional Foods: A special category of food, functional foods, are those modified or naturally rich in compounds that provide additional health benefits beyond their basic nutritional value.

A Multi-Faceted Definition

In the scientific community, the definition of food is not static but rather a dynamic concept encompassing multiple scientific disciplines, including nutrition, chemistry, biology, and sociology. At its core, food is a substance, typically of plant, animal, or fungal origin, that is consumed by an organism for nutritional support. It provides the essential substances—carbohydrates, fats, proteins, vitamins, and minerals—that are metabolized by the body to furnish energy, sustain vital processes, and enable growth and repair. However, this basic definition has evolved to incorporate more nuanced aspects of what food truly is.

The Food Matrix: More Than the Sum of Its Nutrients

Early nutritional science often focused on breaking food down into its individual components. However, modern research emphasizes the concept of the 'food matrix'. This refers to the complex physical and chemical structure of food that influences how nutrients are released, digested, and absorbed by the body. For example, fiber in a whole apple slows the absorption of its sugars, while the sugar in an apple juice is absorbed much faster. This means that the effect of a whole food on the body is greater and different than the effect of its isolated nutrients, a concept known as 'food synergy'. This holistic view helps scientists understand the complex relationship between diet and health more effectively.

Food vs. Nutrition: A Critical Distinction

While the terms are often used interchangeably, scientists make a clear distinction between food and nutrition. As researchers point out, we eat food, not just its nutritional value. Nutrition is the process by which the body assimilates and utilizes the food materials to grow, maintain itself, and reproduce. Food, therefore, is the vehicle for nutrition. The focus on whole foods rather than isolated nutrients is a cornerstone of modern nutrition science, acknowledging the physiological and cultural context of eating. The idea of replacing all food with a single nutritious pill, for instance, is a concept that fails to capture the complexity and psychological satisfaction derived from eating food.

The Role of Processing: The NOVA Classification

With the rise of industrial food production, the scientific community developed systems to classify food based on the extent and purpose of its processing. The NOVA classification, created by a team of Brazilian researchers, is a widely recognized system. It categorizes food into four groups:

Group 1: Unprocessed or Minimally Processed Foods: These are foods that have undergone minimal changes, such as drying, crushing, or pasteurization, without adding chemicals. Examples include fresh fruits, vegetables, nuts, and pasteurized milk.
Group 2: Processed Culinary Ingredients: This group includes substances like oils, salt, and sugar that are extracted from Group 1 foods and used to cook and season dishes.
Group 3: Processed Foods: These are made by adding ingredients from Group 2 to Group 1 foods. Simple industrial processes create items like canned vegetables, cheeses, and artisan bread.
Group 4: Ultra-Processed Food and Drink Products: These are industrial formulations with multiple ingredients, often including additives like colors, flavors, and emulsifiers. Examples include soft drinks, packaged snacks, and instant noodles. This classification is a critical tool for public health experts to study the impact of industrial processing on diet and health.

Functional Foods: Benefits Beyond Basic Nutrition

A newer concept within food science is the 'functional food'. These are foods that offer health benefits beyond their basic nutritional value, often through fortification or enhancement. Examples include orange juice fortified with calcium or cereals with added folic acid. Functional foods can also be natural, like oats containing beta-glucan, which is known to lower cholesterol. This area of food science explores how to improve health and prevent disease through targeted food modifications.

The Human and Cultural Context

Finally, the scientific definition of food acknowledges its profound human and cultural context. What one society considers food may be considered inappropriate in another due to ethical, religious, or personal preferences. Food serves more than a physiological purpose; it provides psychological satisfaction, comfort, and is a centerpiece of social gatherings and traditions. A comprehensive scientific view recognizes that understanding food requires examining its composition, its processing, and the diverse social roles it plays in human societies.

Natural vs. Ultra-Processed Food


Feature	Natural/Minimally Processed Food	Ultra-Processed Food
Composition	Edible parts of plants or animals; few ingredients.	Industrial formulations with many ingredients and additives.
Processing	Simple methods like freezing, drying, or pasteurization.	Complex, industrial processes that often extract substances from whole foods.
Nutritional Density	High in naturally occurring vitamins, minerals, and fiber.	Often high in energy, added sugars, fats, and salt, but low in fiber.
Satiety Effect	Higher satiety due to fiber and natural complexity of the food matrix.	Lower satiety, often leading to overconsumption.
Health Impact	Associated with better health outcomes and disease prevention.	Linked to obesity and other chronic diet-related diseases.

Conclusion: A Holistic View of Food

Ultimately, how do scientists define food? The answer is that they view it from multiple perspectives. At its most fundamental level, food is a substance that provides essential nutrients and energy. However, a complete understanding requires appreciating its complex 'food matrix' that dictates nutrient absorption. It involves distinguishing food as the consumed item from nutrition as the biological process. Furthermore, the scientific definition must consider the degree of processing, as systems like NOVA show that industrial transformation significantly impacts health outcomes. Finally, it is crucial to recognize food's cultural and social significance, which provides psychological satisfaction beyond just physical sustenance. This holistic, scientific approach allows for a much richer and more accurate picture of food's true impact on our health and well-being.

Learn more about food and nutrition at the National Institutes of Health(https://newsinhealth.nih.gov/2023/08/breaking-down-food).

Frequently Asked Questions

The food matrix refers to the complex structure of food that determines how nutrients are released and absorbed during digestion. It's important because it shows that the overall effect of a whole food is different and often more beneficial than consuming isolated nutrients.

Food is the substance consumed for sustenance, while nutrition is the physiological process of digesting and utilizing the nutrients from food to support the body's functions. Scientists emphasize eating whole foods for nutrition, not just consuming isolated nutrients.

The NOVA system classifies foods into four groups based on their level of processing: unprocessed/minimally processed, processed culinary ingredients, processed foods, and ultra-processed foods. It is used to assess the impact of industrial processing on diet and health.

Yes, a comprehensive scientific definition of food acknowledges its social and cultural dimensions, such as its role in traditions and its capacity to provide psychological satisfaction. What is considered appropriate food varies significantly across different cultures.

Functional foods are those that offer health benefits beyond basic nutrition, often through natural compounds or added supplements. Examples include oats with beta-glucan and orange juice fortified with calcium.

No. Scientists analyze food based on its source (plant, animal, fungal), its nutrient profile, and its level of processing. They recognize differences in bioavailability and health impact, such as the preference for unsaturated fats over saturated fats.

Scientific evidence and the concept of food synergy suggest that the combination of naturally occurring components in whole foods provides health benefits that often cannot be replicated by single, isolated nutrients in supplements. The bioavailability and interaction of nutrients are more complex in whole foods.