Part 1: The foundations of nutrition: Mind your Macronutrients


Sharon Sun


July 24, 2022

Ever hear people talking about ‘macros’ like the next big celebrity gossip? They’re important but can sometimes cause confusion in the nutrition realm especially when some are inaccurately classified as ‘bad’. In part one of this series, we’ll digest them further and taste some of the facts. We will highlight their main functions and showcase how they can be supportive to our brain function, cognition and mood. Read on to consume the macronutrients!

What are macronutrients?

Macronutrients or commonly ‘macros’ are termed so because they are needed in ‘large’ amounts whereas micronutrients like vitamins and minerals are needed in smaller amounts. It’s paramount to be including all of these in the meals because they serve absolutely essential functions. Even if you do not plan to exercise for the day (ie. spend a lot of energy), the energy from macronutrients is needed just to keep our hearts beating (ie. basal metabolic rate) and even digest food (thermic effect of food)!

Reminder: While both macronutrients and micronutrients are fundamental, it is more important to consume a variety of whole foods as often as possible rather than be bogged down by numbers and nutrient reference amounts. When we consume a variety of foods containing a balance of all the food groups, we are very likely to meet both our macronutrient and micronutrient needs!


Now carbohydrates tend to get a very bad rap but they are essential! They’re commonly associated with grain foods such as rice, pasta, breads but they are also found in fruits and vegetables (in the form of sugars, fibres, starches) or sugars in dairy products (ie. lactose). In fact, carbohydrates in the form of glucose are actually your body’s preferred energy source. Your body has hundreds of metabolic cycles and each one of them requires (directly or indirectly) sugars as a fast source of energy.

How does this relate to our daily function, cognition and mental function?

Interestingly, the frontal lobes in our brain are very sensitive to glucose. As discussed, glucose is our body’s preferred energy source because of how quickly it can be metabolized and used. Therefore, any changes in mental function might be a primary sign for a nutrient deficiency (1). Experiencing ‘brain fog’, low energy or poor concentration? A prime culprit may be inconsistent amounts of carbohydrates at meal times or even the absence of it (ie. when we are busy working and studying and end up dismissing our hunger cues). Our brains require a constant supply of glucose as fuel to stay focused and attentive!

What can I do next?

Ensuring we include a variety of carbohydrate sources in the diet is critical. On the topic, the type and sources of carbohydrates matter too. Different foods are digested at different rates leading to a slow, moderate or rapid release of glucose into our blood (glycemic index of food). When there’s a fast release of glucose into the blood, our body also tries to quickly compensate (with insulin) to keep our blood sugar levels in-check but this can lead to a big drop in our energy. With that also comes a drop in our attention and mood. This tends to happen with high glycemic foods such as pasta (cooked past al dente) and white breads that are quickly digested by the body and increases blood sugars faster than moderate or low glycemic foods. By no means are these bad foods and we can certainly include them as part of a healthy diet but we want to include a good balance of different foods with different glycemic indexes so that our blood sugars, and hence attention is stable through the day!

Action/Tip:  Include lower glycemic foods such as oats, barley, broccoli and tomatoes often. They are also rich in fibre which help to slow the digestion and absorption of our food and stabilize our blood sugars! Here is a handy guide on the Glycemic Index of common foods.

2. Protein

Protein does wonders for the body! It is made up of amino acids (the building blocks of protein) and 9 of the 20 are essential to the body (meaning we must get them from the diet). We often associate proteins with building muscles but they have additional diverse functions. For one, they can come in the form of digestive enzymes or in other words, be helpers that digest our food! Significantly, amino acids are also used to make hormones, antibodies and neurotransmitters. Whether you are receiving a signal that you are full after a meal (hello, ghrelin), fighting an infection, or just feeling happy throughout the day (serotonin), these are some of the protein or protein-related roles in action. How cool is that?

Serotonin Fun facts: Serotonin is one of the many neurotransmitters that send chemical messages between our brain cells (neurons) or from brain cells to muscles. It is made from the amino acid tryptophan which can be found in foods such as tuna, chicken, nuts and seeds. Specifically, serotonin is involved with mood stabilization, happiness, appetite, emotions and mood (You can start to imagine how important one single component of protein can have such a large impact on our daily functions and interactions) More surprisingly, over 90% of serotonin is made in the gut (1)! More on this and the gut-brain axis here!

3. Lipids/fats

Fats come in many forms and subcategories and can fall into triglycerides, saturated fats, unsaturated fats. They have important functions in building cell membranes, providing insulation and even helping to absorb some vitamins (A, D, E and K). Like carbohydrates, not all are created equal and it is recommended to include healthy unsaturated sources as often as possible. In addition to being a long-term storage form of energy, it has a significant role in brain health. In fact, if you were to take the dehydrated weight of the human brain, most of it would be fats and lipids (2). A specific type lines the outside of the brain cells (neurons) helping to transfer electrical impulses quickly to other neurons. From this information alone, fat plays a huge role in brain function including but not limited to mood, functioning, development and energy.

An oath to Omega 3s

Oh mega goodness! These specific fats are commonly vouched for and for good reasons. These are essential, meaning that the body does not have any enzymes to make them and we must get them from our diets. Omega-3 fats play a significant role in brain and nerve function amongst many others. They are part of the many other fats that can be found in the brain which influence cognitive development. For brain health and mood, they have been used as treatments to prevent degenerative brain conditions and treat depression although larger studies still need to be done (13). It is suggested that these polyunsaturated fats can change the composition of the cell membranes in the central nervous system and affect how serotonin and dopamine (neurotransmitters) are transmitted across brain cells (13). This is one example of two macronutrients (fat and protein derivatives/amino acids) working together synergistically. Many things are connected and that’s one of the many reasons we vouch for a balance of the nutrients!

Action:  Health Canada recommends having at least 2 servings of fish per week to meet omega 3 needs. For vegetarians and vegans, alternatives include having 1-2 tablespoons of chia, flax or hemp seeds or 1/4 cup of walnuts per day.

Nutrition at its simplest

When you realize that these macronutrients help form the basic backbone of brain health (among all other important functions for the rest of the body), it starts to become easier to understand how a well-balanced diet can support our body to meet its essential functions. A good reference for creating balanced meals is the Canada’ Food Guide plate method tool. It supports the eating needs of most healthy individuals without having to worry about exact portion sizes! Using this tool as a guide will allow you to make healthy choices to meet most or all of your nutrient needs. Nutrition does not have to be complex!

Now that we’ve had a taste of all three of the macronutrients, let’s dive into our next series to learn how our gut has a mind of its own!


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