Nutritional Foundation: Basic Terms and Concepts

A macronutrient is an essential nutrient that the body needs in a relatively large amount. These include proteins, fats, carbohydrates, and water. Micronutrients are required in smaller amounts. These include vitamins and minerals. A diet that provides enough essential nutrients, is vital because they provide energy, help build and repair body tissues, and help regulate body functions.

Image source: https://avitahealth.org/health-library/macronutrients-a-simple-guide-to-macros/

Calories

The energy in foods is expressed as kilocalories. Although technically incorrect, people refer to kilocalories as “calories”, which is actually a much smaller unit of energy. You’ll see the term calorie on food labels and used in the lexicon of nutritional discussion, so we will also use it here.

Three of the essential nutrients supply energy:

• Fat=9 calories/gram
• Protein=4 calories/gram
• Carbohydrate=4 calories/gram

Proteins-The Basis of Body Structure

Proteins form important parts of our body’s main structural components: muscles and bones. They also form parts of our blood, enzymes, cell membranes, and some hormones. Amino acids form the building blocks of proteins. There are 20 common amino acids found in food. Nine of these are essential (sometimes called indispensable)

Individual protein sources are considered “complete” if they supply all the essential amino acids in adequate amounts and “incomplete” if they do not. For example, meat, fish, poultry, eggs, milk, cheese, and soy are considered complete proteins. Nuts, dried beans, and peas (legumes) are considered incomplete because they are usually low in one or more essential amino acids. Most incomplete proteins come from plant sources. Here’s the amazing thing though about incomplete proteins…they can combine to create complete sources (wheat and peanuts in a peanut butter sandwich or rice and beans). We now know that proteins consumed throughout the course of the day can complement each other as part of a pool of amino acids the body can draw from to produce proteins.

Fats-Essential for Energy

Fats are the most calorie-dense form of energy (9 calories/gram), so you’re getting a lot of “bang for your buck” when you consume wholesome fats. They typically leave you feeling very satisfied and may make you feel fuller for longer periods of time. Fats are essential for the absorption of fat-soluble vitamins. They provide cushioning and insulation for our bodies. Often demonized in today’s diet culture, fats should not be avoided and are important for our health.

Fats are usually composed of both saturated and unsaturated fatty acids. The dominant type determines the fat’s characteristics. Saturated fats are found mostly in animal products and tropical oils. They are generally solid at room temperature. Unsaturated fats are found primarily in plant foods and are usually liquid at room temperature. Unsaturated fats can be further divided into monounsaturated and polyunsaturated.
You may see polyunsaturated fats described as either omega-3 or omega-6 fats.

Trans fatty acids (trans fats) are unsaturated fats that have undergone a process of hydrogenation. This creates a more solid fat from a liquid oil. Food manufacturers use hydrogenation to increase the stability of an oil, basically making it more “shelf stable”. This means it extends the shelf life of foods made with that oil, and trans fats are often reused when deep frying.

Fats and Our Health

Research continues to evolve and change regarding fats in our diets. What we do know is that they are necessary to maintain certain body functions and should not be avoided all together. Most experts agree that trans fats are somewhat dangerous and should be avoided because of their impact on cholesterol. They raise levels of low-density lipoproteins (LDLs) and also lower high-density lipoproteins (HDLs). Limiting your consumption of trans fats may be helpful in maintaining a more normal total cholesterol level.

Carbohydrates-A Key Source of Energy

Bottom line…carbs are necessary because they supply energy to body cells. Muscles use carbohydrates for fuel in the form of glucose.

Simple Carbs (AKA “sugars”)

Simple carbohydrates are essentially sugars. It doesn’t matter if it’s table sugar (white sugar) or organic honey, it has essentially the same molecular structure. Diet culture and marketing practices have made us think that one is superior, but on a scientific level, they are essentially the same thing. They are found naturally in foods (fruits, milk) and they are added to sodas, candy and desserts to add sweetness.

Complex Carbs

Complex carbs include both starches (potatoes, grains, beans, peas, yams) and dietary fiber. Complex carbs are further divided into refined carbs and whole grains. Through processing, refined carbs are stripped of their nutrients. This leaves a product with the same number of calories as the unrefined product, but lower in fiber, vitamins, and minerals. Whole grains tend to take longer to chew and digest then refined ones. The slower digestive pace makes you feel full sooner and for a longer period.

Carbs and the Glycemic Index

Glucose’s counterpart is insulin. Insulin is a hormone made in the pancreas that is released to help the cells take up glucose and use it for energy and fat storage. The levels of insulin and glucose rise and fall after eating any type of carbohydrate. The more sugary the food, the greater the rise and vice versa. The glycemic index is the measure of how a particular food affects blood glucose levels.

Fiber

Fiber is nondigestible carbohydrates in plants. This is also known as dietary fiber. Functional fiber refers to nondigestible carbohydrates that have been isolated from natural sources or synthesized in a lab. These can be added to foods as a supplement. Fiber is known to help prevent constipation. It is also helpful in slowing the absorption of glucose into the blood after eating. Sources of fiber include all plant foods: fruits, vegetables, wheat, legumes, oats, and barley. Processing of packaged foods can remove fiber.

Vitamins-Organic Micronutrients

Vitamins are carbon containing substances needed in small amounts to help promote and regulate chemical reactions in the body. Vitamins contribute to the production of red blood cells and maintenance of nervous, skeletal, and immune systems. They also act as antioxidants. Humans need 13 vitamins:

• 4 are fat soluble (A, D, E, and K)
• 9 are water soluble (C , thiamin, riboflavin, niacin, vitamin B-6, folate, vitamin B-12, biotin, and pantothenic acid)

Sources of vitamins: fruits, vegetables, and grains. The human body must obtain most of the vitamins it needs from food sources. While vitamin deficiencies are relatively rare in the US, many Americans consume lower than recommended amounts for several reasons. They include food insecurity and food sensitivities. Supplementation with a multi-vitamin may be beneficial if you are unable to get adequate vitamin amounts through your diet.

Minerals-Inorganic Micronutrients

Minerals are inorganic compounds needed in relatively small amounts for regulation, growth, and maintenance of body tissues and functions. There are about 17 essential minerals. Minerals commonly lacking in the American diet include iron, calcium, magnesium, and potassium. Anemia and osteoporosis are examples of mineral deficiencies.

Water

Water is the most common component in foods and human body. It is used in digestion and absorption of food in the lower intestine. Water is the medium in which most chemical reactions take place in the body.

Dietary Guidelines

In 2015, the Dietary Guidelines Advisory Committee identified nutrients that Americans tend to over or under-consume.

• Added sugars: should be less than 10% of your daily calories
• Fats: focus on limiting saturated and trans fats rather than all fats
• Sodium: aim for no more than 2300mg/day
• Shortfall nutrients: calcium, vitamin D, potassium, iron, and fiber are of concern

See more of their work here.

The Food Label-Take it Or Leave It

The food label or Nutrition Facts on a food item is something we’ve all observed. While the label provides information about the contents of the food, this insight may be helpful or harmful depending on where we are with our relationship with food. The current food label was created in light of the growing “obesity epidemic” yet the rate of obesity and overweight has not changed since it was introduced. The entire US population has been exposed to some sort of food label for nearly 2 decades and the rates of obesity continue to rise. One positive take on the current food label is that it does show ingredients and can be helpful for those people who have food allergies or sensitivities.

Image Source: https://www.fda.gov/food/new-nutrition-facts-label/how-understand-and-use-nutrition-facts-label

Information on the Food Label

• Number of calories/serving
• Total number of servings in the package (e.g can or box)
• Total fat
• Cholesterol amount
• Sodium amount
• Total carbohydrate
• Protein amount
• % daily value (based on a 2,000-calorie diet)
  
  

References

• Mind Over Munch. (2016, January 5). Macros: explained! mind over munch kickstart 2016. [Video]. YouTube. https://www.youtube.com/watch?v=7HXkkanqPKA&t=7s
• Ted-Ed. (2014, October 6). How do vitamins work? – Ginnie Trinh Nguyen. [Video]. YouTube. https://www.youtube.com/watch?v=ISZLTJH5lYg
• US Department of Health and Human Services. (2021). About the dietary guidelines. https://health.gov/our-work/food-nutrition/about-dietary-guidelines#:~:text=The%20Advisory%20Committee%20examines%20current,provide%20comments%20throughout%20that%20process