What are Macronutrients (AKA Macros)?

Macronutrients (macros) are our main sources of staying alive!  They consist of fats, carbohydrates, protein [and fiber].  These macros are extremely important in our daily lives – they help us maintain our energy levels, they help us build muscle, and they also help our nervous system stay in tip-top shape [from a microbiology standpoint].  Here’s a brief overview of each macro.

FATS (AKA Lipids)

Fats are broken up into four (4) different categories:  triglycerides, fatty acids, phospholipids, and cholesterol; however, most fats found in food sources are composed of triglycerides – which are fatty acids stored within the body¹.  Fats provide us with more energy levels than carbohydrates and protein do, thus yielding about nine (9) calories per one (1) gram of fat¹ ².  Some of us have heard of the two (2) main essential fatty acids:  omega-6 (linoleic acid) and omega-3 (linolenic acid); according to Baechle¹, it is recommended to consume 5-10% of energy from omega-6 fatty acids and 0.6-1.2% from omega-3 fatty acids; however, current research suggests an omega-6 to omega-3 ratio within one’s diet should be close to 1:1.

Fats’ primary functions include¹ ²:

  • Insulation/protection of major organs
  • Hormonal regulation
  • Maintaining cell membranes
  • Development/function of the nervous system
  • Muscle cell energy (specifically from fatty acids)
  • Metabolism homeostasis


Carbohydrates (carbs) are classified into two (2) main groups:  monosaccharides (simple carbohydrates) and disaccharides/polysaccharides (complex carbohydrates).  Monosaccharides are primarily “single-sugars”, for example glucose and fructose¹.  Glucose is the primary energy source located in the bloodstream and withholds glycogen, which is the primary energy source stored in muscle tissue as well as the liver; glucose is also commonly used and found in sports drinks, such as Gatorade¹ ².  Fructose is naturally found in fruits and vegetables, thus having a decreasing effect of blood insulin levels on maintaining blood glucose homeostasis¹ ².  Polysaccharides are known as complex carbohydrates, as examples include starch, fiber, and glycogen¹ ².  Carbohydrates yield four (4) calories per one (1) gram of carb¹ ².  Baechle¹ recommends to combine intake of both simple + complex carbs into one’s nutrition.

Carbs’ primary functions include¹ ²:

  • Immediate energy
  • Sustained activity levels
  • Rise of low blood glucose levels
  • Brain/nervous system function


Protein is made up of amino acids (AAs), which serve as the building blocks of protein¹ ².  There are two (2) types of AAs:  essential AAs and non-essential AAs.  Non-essential AAs are synthesized by the human body naturally and do not need to be consumed through food; however, essential AAs must be consumed via food because the body cannot produce it independently¹².  There are nine (9) essential AAs, with Leucine receiving most of the current research hype (this is left for another story…)¹ ².  As with carbs, protein yields about four (4) calories per one (1) gram of protein¹ ².  The majority of the body’s protein is found in skeletal muscle, organs, and bone tissue¹.  It is currently recommended that protein intake should fall somewhere between 0.8g to 1.0g per one’s body weight – with about 0.8g per body weight being most beneficial at this time³.

Proteins’ primary functions include:

  • Building/maintaining muscle
  • Building/maintaining strength
  • Increasing metabolism
  • Increasing lean body mass
  • Cell/tissue repair


Fiber (dietary fiber) is considered a classification of carbohydrates¹.  It has long been studied that one must essentially include fiber within their dietary intake¹ ².  Dietary fiber intake has been shown to aid in improving several digestive disorders including diverticulitis, constipation, heart disease, colon cancer, and diabetes¹ ².  Fiber provides us with a sense of “fullness” without adding more calories once ingested – it can be found in fruits, nuts, seeds, vegetables, and oatmeal to name a few¹ ².  It is suggested to consume somewhere between 25-35g of fiber per day¹ ².

Fibers’ primary functions include¹ ²:

  • Sensation of satiety
  • Acting as a thickener in various food products
  • Decreasing constipation
  • Decreasing cholesterol levels
  • Homeostasis of blood glucose levels

By understanding the basic proponents of macros, we can determine how to properly fuel our bodies at an individualized, optimal level.  Once we understand this foundation of knowledge, then the flexible dieting approach only makes sense to provide ourselves with appropriate intake of each macro.  As my aunt says, “garbage in = garbage out”; and if we unknowingly put things in our bodies and hoping to receive positive outcomes, then we cannot hold ourselves accountable.  Put it this way, if you cheat on a school exam without studying the topic, then your outcome probably won’t be as successful as you expect it would be!  I hope this helps with your endeavor on flexible dieting and nutrition – remember to enjoy the process and hold yourself accountable!


  1. Baechle, T, Earle, R.  Essentials of Strength Training and Conditioning.  Champaign, IL:  Human Kinetics; 2008.
  2. Powers, S, Howley, E.  Exercise Physiology:  Theory and Application to Fitness and Performance.  New York, NY:  McGraw-Hill; 2007.
  3. The Myth of 1g/lb:  Optimal Protein Intake for Bodybuilders.  Bayesian Bodybuilding Web site. http://bayesianbodybuilding.com/the-myth-of-1glb-optimal-protein-intake-for-bodybuilders/. Accessed February 1, 2016.

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