Nutrition is one of the most common places for people to start on their wellness journey. There’s a lot of good and bad information out there regarding nutrition. This post is meant to be a general resource based on foundational nutritional principles along with the clarification and/or purpose of common nutritional terms.
Disclaimer: This is not advice nor a recommendation. The amounts listed are straight from the USDA Dietary Guidelines for the generic population and are not specific to you. Discuss specifics with your medical/licensed professional.
Calories
Calories are simply a unit of measurement of the amount of energy content in food. The food we eat converts into energy and usable components during digestion which supplies our body with power and necessary elements for the body’s biological processes.
Energy Balance
The idea of energy balance comes from the first law of thermodynamics: energy cannot be created, nor destroyed. Energy is transferred from the food we eat, via digestion, and is either used or stored for later. Whether you’re eating an apple or a cupcake, that food has a certain amount of calories within it that your body is taking in (calories in) and your body must use those calories (calories out). If the calories are not used, then they are stored for later. Often either in the form of adipose tissue (fat) or muscle.
Energy Expenditure
Energy expenditure is a term for classifying how our body uses the energy it derived from the food we consumed.
Our basic biological processes require energy in the form of calories to function. Even if we slept all day, our bodies still use at least 1000 calories daily to run body processes just to keep us alive. We call this our Resting Metabolic Rate. Another form of energy expenditure is the Thermic Effect of Feeding which is the amount of calories we use to digest our food.
After our body uses all the calories it needs, the remaining calories that were not utilized are stored until they are needed. This is where ‘energy balance’ comes into play. It is a balancing act of supplying the body with enough energy to run its process and function properly while avoiding excess energy that it will have to resort to storing somewhere in the body.
Macronutrients aka Macros
Macronutrients are nutrients the body needs in large amounts, hence “macros”. This is where we derive most of our calories from. Whereas micronutrients are the vitamins and minerals our body needs for optimal functioning, however they are not required in large amounts as macronutrients.
Alcohol is not technically a macronutrient because there is no nutritional value, however alcohol does have caloric content and costs us calories when we consume it. Hence, “empty calories”.
Protein
Protein is required for humans to consume via our diet to survive as it is found in all body tissues and our body cannot produce its own protein. Protein is most famous for its effect on muscle mass and function. It is also essential for growth and repair of tissues. Enzymes are proteins important for activating chemical processes in the body. Protein takes longer to digest which is why it keeps you fuller for longer than carbohydrates.
The usable component protein is broken down into is called an amino acid when in a single unit. When amino acids are attached together like a chain they are called peptides.
Protein can come from plant and animal sources. Animal protein is always a “complete” protein, whereas most plant proteins are “incomplete”. A protein is considered “complete” when it has all of the essential amino acids that the body requires, but cannot produce itself and therefore must be obtained from our diet. You can combine different incomplete plant sources of protein to obtain the “complete” protein effect as long as all essential amino acids are accounted for. Another reason why diet variety is crucial! It’s also important to note, when it comes to animal protein sources, to be cautious of the saturated fat content. We want to try and keep saturated fat consumption under 10% of our calories daily.
Fats
Dietary fats are essential to survive as well. Like protein, we can’t make dietary fats within our body so we must consume them from our diet. Dietary fats are required in body functioning for processes like hormone production, nutrient absorption, and healthy cell growth. Fats are also a good source of energy as they come in at 9 calories per gram in comparison to protein and carbohydrates which are only 4 calories per gram. Additionally, like proteins, dietary fats are slow to digest and keep us fuller longer.
Fats are broken down into fatty acids and glycerol. There are 4 classes: saturated, monounsaturated, polyunsaturated, and trans-fat. We want to avoid trans fat and aim for saturated fat to be under 10% of our daily calories.
Omega 3 and 6 are polyunsaturated essential fatty acids which, like essential amino acids, are essential for our health and functioning but cannot be produced by the body and must be consumed in our diet. Omega 9 is a monounsaturated fat that can be produced by the body. Therefore it is not an essential fatty acid, but it is still beneficial to our health.
Carbohydrates
Interestingly, carbs aren’t required in the way that protein and dietary fats are for survival because our body can break down protein and fat for energy if necessary. However, carbs do contribute to maximal health.
Carb content in food is either starch, fiber, or sugar. All carbs are broken down into units of sugar that we call mono/disaccharides. Healthy diet patterns typically are high fiber, low added sugar. It’s recommended to limit added sugars to be 5-10% of our daily calories and to aim for 30 grams of fiber per day.
Refined carbs are “processed carbs” through which the fiber and micronutrients have been removed. Common examples are white bread and pasta. Unrefined carbs, like “whole grain” options, are typically good sources of fiber, micronutrients, and phytonutrients. Even if the caloric content is similar, the whole grain or unrefined carb option is considered healthier because the beneficial nutrients are not lost in processing!
Micronutrients: Vitamins, Minerals, Phytonutrients, & Bioactive Compounds
Micronutrients will have their own post (see Nutrition 102) but as an introduction: micronutrients must be obtained through our diet and are necessary for basic functioning and bodily processes. While you can supplement micronutrients in isolation, our current understanding is that consuming micronutrients via whole foods and mixed meals is most optimal. The hypothesis is that the interaction of the micronutrients from these whole food, mixed meal forms allows for optimal interaction and absorption. Micro refers to how we do not need micronutrients in as large amounts as proteins, fats, and carbohydrates.
Lastly, for good measure:
This is not advice nor a recommendation. The amounts listed are straight from the USDA Dietary Guidelines for the generic population and are not specific to you. Discuss specifics with your medical/licensed professional.