The Big 3 Macronutrients – Fat, Protein and Carbohydrate

We often see or hear claims about a food product being “low in carbs”, “high in protein” or “fat free”. We thought it would be a good idea to get back to the basics and do a post on these 3 macronutrients. They are the source of practically all calories in food. They are called macro-nutrients because we need these in large quantities to function properly.

Foods generally contain different proportions of fats, protein, carbs and water. However, some foods are made up of only one macronutrient such as oil (pure fat) or sugar (pure carbohydrate). Let’s review each one of these macronutrients:

1. Carbohydrates (Carbs)

Contrary to many fad diets out there – Carbs are the main source of energy for our bodies. The most simple form of carbohydrate is glucose, the only substance our brains use for energy. Our kidneys, heart and nervous system also use glucose to function properly. Out of our total energy intake for the day, it is recommended to get around 45-65% of energy from carbs.  So in a 2000 calorie diet this is 900 to 1,300 calories a day, or 225 – 325 grams (One gram of carbohydrate provides 4 calories). Our body can use the energy from carbs immediately, or store it for later use. Common sources of carbohydrates include breads, cereals, pasta, rice, potatoes, fruits and vegetables.

What are some good sources of carbs?

When choosing a carbohydrate it is important to select something that is high in fiber, low glycemic index and as least processed as possible. Examples include wholegrain bread, apples, sweet potatoes, brown rice and oats.

2. Proteins

We only need about 10-35% of our diets to come from protein – most Americans get more than ample protein every day. Proteins are important for repair and growth of tissues, building muscle, enzymes, hormones, amino acids and our immune system. Protein isn’t used immediately for energy – it’s more of a backup for our body. One gram of protein, like carbs, also provides 4 calories.

Choose foods that have high quality protein: lean meats, fish, poultry, low fat cheese, milk, yoghurt, eggs, legumes, soy, nuts and seeds.

3. Fats

Fats should make up about 20-35% of our diet. Unfortunately, they’ve been getting a bad reputation for decades. Nonetheless, fats are essential in our diet. Fats are important for protecting our organs, maintaining cell membranes, promoting growth and development and absorbing essential vitamins. One gram of fat contains about 9 calories (more than double a gram of carb or protein, hence the vilification).

Which fats are good for you? Choose foods that contain unsaturated fats over saturated fats, such as oily fish, nuts and seeds, olive oil, avocado and canola oil instead of full cream milk, deep fried foods, cream, butter and animal fat.

So there you have it – the big three.

For those of you that are wondering where alcohol fits into the picture, it isn’t technically considered a “macronutrient” because our body doesn’t need it to function. However, if it is contained in foods or drink it adds quite a chunk of energy, almost the same amount as fat! One gram of alcohol has 7 calories!

There are many mixed messages out there regarding low carb, high protein diets. Most health professionals will not recommend these extreme diets as a way of obtaining enough nutrition for an active, healthy life.  Following a balanced diet that contains carbs, protein and fat in the right proportions should give you all the nutrients you need!

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  • Brian

    In your discussion about carbs, you say that carbs are our main source of energy, which is true. But isn’t it also true that our body can create energy from other sources? We don’t “need” carbs, but should eat carbs? You also mention that they are stored for later use. Does that mean they are stored as fat? If that is true, would that mean we should be careful about how many carbs we consume? Thoughts? 

    • carol

       Carbs are stored as glycogen. Fat is longer term storage when you’ve eaten too much of anything.

  • Lil Bear Studley

    Great article! I’m an athlete, and for about 10 months went high protein and low carb, to “lean out”. Yes, it worked, but I did a lot of damage to my body in the process. I’ve been eating better proportions for a couple months now, and am still repairing my health systems. Eat those carbs, people!

  • Carol

    You probably meant to say (regarding which fatty foods to eat): “those that are lower in saturated fats,” because all fat-containing foods contain a mix of fatty acids (saturated and unsaturated). But it’s more complicated than that, because some saturated (and unsaturated) fats are more health-friendly than others … and food labels don’t give this much info about fats (not that this would be easy to represent/explain/fit on a food label).

  • Sandra Homemaker

    I don’t understand why a low carbohydrate diet is so often referred to as a fad diet. This is the oldest “diet” known to man. Early hunter-gatherers consumed foods high in both protein and fat and mostly low in carbohydrates. It was not until the advent of industrial agriculture that we began to eat such a large amount of carbohydrates on a regular basis.

    When most people hear low-carb they think Atkins. Atkins is but one of many doctors and educated people who advocate low carbohydrate diets. Others include: 1797 Dr. John Rollo, 1863 William Banting, 1888 James Salisbury, 1967 Dr. Irwin Stillma, 1967 Dr Wolfgang Lutz, and many many more in recent years – The Zone Diet, The Makers Diet, Protein Power, Paleo Diet. This is nothing new. So many people have written about low carb diets because they really work!

    For three decades we have been told that for our health and to lose
    weight we all should eat a low fat diet based on carbohydrate foods: breads,
    pasta, fruit and vegetables. Over this same period there has been a dramatic increase in obesity and
    related diseases.

    Instead of blindly following the US government’s recommendations of what constitutes a healthy diet, you may find it helpful to do a little research on your own. A good place to start is with the work of Gary Taubes. He has written two books on the subject: Good Calories Bad Calories, and Why We Get Fat. Both of these books are thoroughly cited with references to scientific studies. Or you could just start with one of his lectures on YouTube: – interesting stuff!

    Also, saturated fats are not the enemy. Certain high-quality saturated fats are essential for human life and vital for optimal physical and mental development. Read more about that at

    • carol

      Humans are omnivores… always have been (look at your teeth). In prehistoric times they ate whatever they could find, which varied widely with region, season, etc. Some areas had mostly fruits and roots to eat (carbs), and some areas/seasons there was mostly meat. Starvation was more of an issue than shunning carbs, so foods packed with the most energy (nuts and fatty meat) would provide the most bang for the buck. But it’s not like they had a cafeteria where they could choose. And constant physical activity made it almost impossible to become overweight on ANY diet. Today is very different — food is available all the time. If people aren’t expending as much energy as they’re taking in via calories (from any source), they will get fat. If someone has disputed that in a diet book, then yes, it is a fad.

  • Tatiana

    This is so retro. The only important things are trans-fat and omega-3. Used to be beta-carotene but that got lame.

  • Lol



    i am NOT going to follow u on THE BOOK

  • sephora

    I did understand when they say

    Your job is to create menus for one day that include three meals and one snack, using a variety of foods, and without repeating meals. Your menus need to provide all of the protein, carbohydrates, and fats that you need. You should not go over the recommended daily amounts. You should also check the calories on your menus. For teenagers, daily requirements are:

    GirlsBoysProtein44 grams59 gramsCarbohydrates285 grams375 gramsFats55 grams97 gramsTotal kcal/day2200 kcal2800 kcal can you help me with that ?

  • Drew Marshall

    Carbs are not essential. Period. If we need to eat them (as is the case to avoid starvation) than our bodies can utilize the energy they provide. That being said, our bodies are designed to never need a carb to survive. If you live in a 1st world city and eat carbs, you are eating them by choice not by need. They should not be on the list.