Nutrition and Health

What is Nutrition?

Simply put, food is the plants and animals that we eat, and nutrition is how food affects the health of the body. According to the Academy of Nutrition and Dietetics, “Food is essential—it provides vital nutrients for survival, and helps the body function and stay healthy. Food is comprised of macronutrients including protein, carbohydrate and fat that not only offer calories to fuel the body and give it energy but play specific roles in maintaining health. Food also supplies micronutrients (vitamins and minerals) and phytochemicals that don’t provide calories but serve a variety of critical functions to ensure the body operates optimally.”1 (Phytochemicals are compounds found in plants that give them their smell, taste, and color. They are not technically nutrients, but many have been shown to affect human health.)

fruits and veggies

The study of nutrition goes beyond just a discussion of food and the nutrients needed by the body. It includes how those nutrients are digested, absorbed, and used by the cells of the body. It examines how food provides energy for daily activities and how our food intake and choices impact body weight and risk for chronic diseases such as heart disease and type 2 diabetes. It also provides insight on behavioral, social, and environmental factors that influence what, how, when, and why we eat.2 Thus, nutrition is an important part of the overall discussion of health and wellness.

How Nutrition Affects Health

The World Health Organization (WHO) defines health as “a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity.”3 The WHO recognizes nutrition as a critical part of health and development, noting that better nutrition is related to:4

  • improved infant, child and maternal health
  • stronger immune systems
  • safer pregnancy and childbirth
  • lower risk of non-communicable diseases (such as type 2 diabetes and cardiovascular disease)
  • greater longevity
  • greater productivity, creating opportunities to break cycles of poverty and hunger

Malnutrition, including both undernutrition and overnutrition, is a significant threat to human health. In fact, nutrition is associated with four of the top ten leading causes of death in the United States, including heart disease, cancer, diabetes, and stroke.5

Figure 1.1. Age-adjusted death rates for the 10 leading causes of deaths: United States, 2016 and 2017

Nutrition can affect the health of the mind as well as the body. For example, some research suggests that the foods people eat can influence their mood. A 2019 study of moderately-depressed people aged 17 to 35 years old found that when half of them shifted towards a Mediterranean-style eating pattern for 3 weeks—emphasizing more fruits and vegetables, whole grains, lean protein sources, unsweetened dairy, fish, nuts and seeds, olive oil, and spices—their depression levels decreased compared to participants who continued their usual eating habits. Some (but not all) other studies have also found links between healthier diets and decreased risk of depression. It’s not clear why this might be, but researchers speculate that decreased inflammation or changes in the body’s microbiome caused by these dietary patterns may play a role in brain functioning and mental health.6 This is an area that requires much more research, but as you’re thinking about dietary choices, it’s worth thinking about how foods make you feel.

In addition to nutrition, health is affected by genetics, the environment, life cycle, and lifestyle. One important facet of lifestyle is personal dietary habits. Dietary habits include what a person eats, how much a person eats during a meal, how frequently meals are consumed, and how often a person eats out. Other aspects of lifestyle include physical activity level, recreational drug use, and sleeping patterns, all of which play a role in health and impact food choices and nutrition status. Following a healthy lifestyle improves your overall health and well-being.

Two young black women smiling and hugging, while enjoying themselves on the beach.

VIDEO: Little Changes” by Patrick Mustain, Vimeo (May 22, 2014), 3:40 minutes.

Personal Choice: The Challenge of Choosing Foods

There are other factors besides environment and lifestyle that influence the foods you choose to eat. Food itself can regulate your appetite and how you feel. Multiple studies have demonstrated that some high-fiber foods and high-protein foods decrease appetite by slowing the digestive process and prolonging the feeling of being full (also called satiety). Making food choices that maximize nutrient intake and satiety can help manage how much you eat and how long before you eat again.

Food also has social, cultural, and religious significance, all of which impact the foods we choose to eat. The social meanings of food affect what people eat, as well as how and when. Special events in our lives—from birthdays to funerals—are commemorated with equally special foods. Cultural influences and upbringing can also shape an individual’s food habits. Being aware of these factors can help people make healthier food choices, and still honor the traditions and ties they hold dear.

A family of three (mom, dad and daughter) sitting at a glass round table, enjoying a meal of rice and chicken. The young child is feeding the mom a bite of food.

Factors that Drive Food Choices

A number of other factors affect the dietary choices individuals make, including:

  • Taste, texture, and appearance. Individuals have a wide range of taste preferences, which influence their food choices. For example, some people dislike milk and others hate raw vegetables. Foods that may be unappealing at first to some people, like vegetables or tofu, can often be adapted to meet most taste preferences, and people can learn to like foods over time with repeated exposures.
  • Economics. Access to fresh fruits and vegetables may be limited, particularly for those who live in economically disadvantaged or remote areas, where affordable food options are limited to convenience stores and fast food.
  • Early food experiences. People who were not exposed to different foods as children, or who were forced to swallow every last bite of overcooked vegetables, may make limited food choices or experience food aversions as adults. On the other hand, those exposed to a variety of foods in the setting of pleasant family meals, are more likely to maintain those same eating habits in adulthood.
  • Habits. It’s common to establish eating routines, which can work both for and against optimal health. Habitually grabbing a fast food sandwich for breakfast can seem convenient, but might not offer substantial nutrition. Yet getting in the habit of drinking an ample amount of water each day can yield multiple benefits.
  • Culture. The culture in which one grows up affects how one sees food in daily life and on special occasions.
  • Geography. Where a person lives influences food choices. For instance, people who live in Midwestern US states have less access to seafood than those living along the coasts.
  • Advertising. The media greatly influences food choices by persuading consumers to eat certain foods.
  • Social factors. Any school lunchroom observer can testify to the impact of peer pressure on eating habits, and this influence lasts through adulthood. People make food choices based on how they see others and want others to see them. For example, individuals who are surrounded by others who consume fast food are more likely to do the same.
  • Health concerns. Some people have food allergies or intolerances and need to avoid certain foods. Others may have developed health issues which require them to follow a low salt diet. In addition, people who have never worried about their weight have a very different approach to eating than those who have long struggled to change their weight.
  • Emotions. There is a wide range in how emotional issues affect eating habits. Food can be a source of comfort, such as the taste of a favorite dish from childhood. Or, for people with a history of disordered eating, it may also be a source of anxiety. When faced with a great deal of stress, some people tend to overeat, while others find it hard to eat at all.
  • Green food/Sustainability choices. Based on a growing understanding of diet as a public and personal issue, more and more people are starting to make food choices based on their environmental impact. Realizing that their food choices help shape the world, many individuals are opting for a vegetarian diet, or, if they do eat animal products, striving to consider animal welfare and sustainability in their choices. Purchasing local and organic food products and items grown through sustainable products can help to shrink the environmental impact of one’s food choices.





  • 1Academy of Nutrition and Dietetics. (2019). How to Explain Basic Nutrition Concepts. Retrieved December 18, 2019, from
  • 2Medline Plus. (2019). Definitions of Health Terms. Retrieved from
  • 3World Health Organization. (n.d.) Constitution. Retrieved from
  • 4World Health Organization. (2018, February 22). Nutrition. Retrieved from
  • 5Centers for Disease Control and Prevention. (2017, March 17). Leading Causes of Death. Retrieved from
  • 6Aubrey, A. & Chatterjee, R. (2019, October 19). Changing Your Diet Can Help Tamp Down Depression, Boost Mood. Retrieved from

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Nutrition: Science and Everyday Application, v. 1.0 Copyright © 2020 by Alice Callahan, PhD; Heather Leonard, MEd, RDN; and Tamberly Powell, MS, RDN is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License, except where otherwise noted.

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