What is Nutrition?

Objectives

By the end of this lesson, you should be able to:

Define nutrition
Identify and discuss factors that determine our food choices
Identify macro, micronutrients and other micro-components of food and determine their general functions
Define calorie
Calculate calorie is food
Discuss the role of supplements in the diet
Discuss the quality of the American diet
Determine how to identify credible health information and research
Explain how the Scientific Method works

Lesson Summary

A healthy person is someone who is free from disease or disease conditions, has a healthy body weight and maintains habits that are consistent with sustaining good mental, emotional and physical well-being.
Being healthy is influenced largely by lifestyle choices such as
- Eating well
- Exercising moderation in diet
- Keeping hydrated
- Exercising
- Getting enough rest
- Getting exposure to clean air and plenty of sunlight
Several factors influence our food choices e.g.
- Culture: Where we live and associated traditions
- Social events: e.g. we associate
  - watching movie and eating popcorn
  - drinking alcohol with St. Patrick’s day
  - Eating lots of food at thanksgiving or while attending a party
- Cost: The affordability of the food. We can buy more of it if it’s cheap
- Convenience: How much time it takes us to prepare the food. It’s easier to grab fast food when we are busy
- Habits: We may have a habit to-
  1. Eat cereal in the morning
  2. Skip breakfast
  3. Snack when we are studying
- Emotion: We tend to eat more when we are celebrating. Some people will also eat more in response to feeling depressed
Nutrition is the study of how nutrients are utilized in the body and how they affect our heath. This is different from food science that studies the physical and chemical properties of food and the science behind how foods products are made.
Nutrients are divided into macro and micronutrients. Macronutrients are nutrients that are needed in large amounts while micronutrients are needed in small amounts.
Examples of macronutrients:
- Lipids
- Carbohydrates
- Proteins
The three macronutrients provide us mainly with energy
The energy that we get from food is called kilocalorie or just calorie for short
- We get 4 calories of energy from 1 gram of protein
- We get 4 calories of energy from 1 gram of carbohydrates
- We get 9 calories of energy from 1 gram of lipid (fat of oil)
Examples of micronutrients
- Vitamins
- Minerals
Micronutrients are needed to facilitate the metabolic reactions that are involved in breaking down the macronutrients to produce energy. In other words eating carbohydrates, proteins and lipids is useless without the vitamins and minerals that play a role in unlocking the energy
Food contains phytochemicals. These are components that are not nutrients but play a key role in keeping us healthy e.g. alkaloids, anthocyanins, carotenoids, flavonoids, and phenolic acid
Some health benefits of phytochemicals include anti-ageing, anti-cancer and healing benefits
Although the United States is a wealthy nation, many suffer from poor diet. This is mainly due to bad choices about what people eat. The typical American diet is characterized by high saturated fat (a bad fat), high salt, high cholesterol, and low fiber. These contribute to high incidences of obesity (65% of Americans are overweight) and heart disease(leading cause of death in America)
American spend 40% of their food budget outside of the home
Be careful who you listen to when it comes to health advice. There is a lot of misinformation out there. As Mark Twain said “Be careful about reading health books. You could die from a misprint”
Take advise from credible websites such as government research websites e.g. NIH, peer-reviewed journals, and qualified health professionals
If you want to know if a website is credible, ask these questions:
- What’s the purpose of the site? Is it set up mainly to sell you something?
- Do they show their credentials?
- Is their potential bias based on who is funding or advertising on the site?
- Do they reference their sources?
- How credible are their sources?
- How current in the information?
- Does the site provide you with contact information to reach someone?
Credible websites will:
- Clearly describe the purpose of their site
- Show their credentials or otherwise demonstrate evidence that they know what they are talking about e.g. referencing credible sources
- Will be unbiased. If they are being paid to promote the information, they are likely biased
- Will provide contact information about how to reach them
The scientific method is a process by which scientists and researchers discover and communicate new information about world. The process involves
- Making an observation
- Coming up with a hypothesis that explains the observation
- Conducting experiments to prove or disprove the hypothesis
- Analyzing the data based on the experiments
- Confirm hypothesis or use data as basis for new study
- Communicate results
- When enough researchers repeat the experiment and come up with the same findings there is consensus in the research community on the validity of the findings
Two types of research following the scientific method include:
- Observational research: Research that involves observing subjects in their natural setting without any manipulation e.g. observing performance in a college biology class based on where they went to high school. An example of an observational research is an epidemiological study which is a study of health in populations, its causes and distribution.
- Experimental Research: Research that involves manipulating subjects e.g. trying to figure out the success of students in a biology class based on teaching methods (face-to-face versus online); or trying to figure out the effect of a drug. One group is given a placebo (sugar pill) and the other is given the real drug.

Key Definitions

Nutrition: The study of nutrients and how it’s utilized in the body
Macronutrients: Nutrients that gives us energy (protein, lipids and carbohydrates), and are needed in large amounts
Micronutrients: Nutrients that do not provide energy but are involved in metabolic reactions to unlock energy from macronutrients. They include vitamins and minerals
Calorie: The unit of energy derived from food
Phytochemicals: Small chemicals in food that do not provide nutritional value but have several therapeutic effect on health and healing
Scientific Method: The step-by-step process that scientists and researchers use to discover and communicate new information to the world
Epidemiological research: A type of observational study in which disease, their cause and distribution, is studied
Single-blind experiment: A research where only the researcher knows the treatment given to the subjects
Double-blind experiment: A research where neither the researcher nor the subjects know what treatment is given. This is to avoid bias
Placebo: A sugar pill given in place of a real drug in an experiment
Registered Dietician Nutritionist: A health professional who has completed accredited training and supervised practice in nutrition from a university or college in the US
Licensed Dietitian Nutritionist (LDN): A recognized expert in nutrition based on education and meeting the requirements of a state licensing board