Nutrition 101: Macronutrients (carbs, fat and protein)
Updated: May 29, 2020
What is a balanced diet? Well, basically it’s eating the right amount and type of food to get all the nutrients the body needs in the right amounts. A nutrient is a substance that provides nourishment essential for growth and the maintenance of life. Your body needs over 40 types of nutrients! The food you eat gets broken down into nutrients. Nutrients are the building blocks of the body. Not only to build and repair the structure of the body, but also for all the functions of the body like moving, thinking, heart beat, breathing, etc, etc. For my dietetics degree, I had to take the highest class of biochemistry, which is all the reactions and pathways in the body. I had to learn what nutrient is required for everything the body does, and there are thousands of spots where the nutrients are required (represented as dots in the photo below, notice how many dots there are!). That is why when someone is eating an unhealthy diet, I wonder what functions their body is not able to perform without nutrients. The burden of knowledge I guess;)
There are many types of nutrients, the main groups are macronutrients and micronutrients. Macronutrients are those we need in larger quantities (protein, carbohydrate, fat and water). Water is considered a macronutrient because it is essential for the body to function and is needed in large amounts (actually the body is mostly made of water!). Micronutrients are those we need in smaller quantities, but they are still essential (vitamins and minerals).
This article is going to focus on the macronutrients: purpose, and how to get the right amount and type for healthy balanced diet. My next article is going to be on micronutrients. Again, I have a dietetics and medical degree, and it’s still difficult to interpret information. But this is knowledge and conclusions I have drawn.
Scientists and health professionals have figured out what percent of calories of a diet is balanced for each macronutrient. You have probably seen the pie graph with % of calories from each macronutrient.
I do not like that pie graph because it is misleading, since calories and grams are not the same. So for some nutrition 101: Calories is a measurement of energy, grams is a measurement of weight. Carbs and protein give us 4 calories of energy per gram, but fat gives us 9 calories per gram. So the % of calories is not grams, fat is double the calories per gram, so it’s about half the amount in a balanced diet. For instance, in a 2000 calorie diet: 50% carbs is 1000 calories, 25% protein is 500 calories, and 25% fat is 500 (this example is simplified the average %, it can fluctuate 10-20% and doesn’t have to be exact). So that makes it look like you can eat ¼ of your plate as fat?! Not so fast: Those calories converted to grams are in below table, so fat amount is actually about 1/10 of your plate. So when looking at your daily intake amount in grams, about half carbs (and that’s more than just bread as you’ll learn below), about 1/3 protein, and about 1/10 fat (since fat is double calories, the actual amount in grams is small).
The main purpose of carbohydrates is for energy. All carbohydrates are broken down to the building block glucose which your body uses for energy. Relatively little is required, because the body can turn glycerol (a building block of fat) and amino acids (the building block of protein) into glucose. The lowest amount is what is needed by the brain, about 50-100 grams per day. But it is an easy form of energy, so the typical balanced diet has about 50% of calories from carbohydrates.
There are 2 main types of carbohydrates: simple and complex. Complex is in the natural state with protein and nutrients. Such as in vegetables, whole grains, fruits and dairy (yes lactose is a carbohydrate). Simple is just the white starchy part, where humans thought “this white stuff is yummy, let’s take it out and make stuff from it”, like white bread, cookies, cakes, etc. The reason it tastes so good, is because it is quickly converted to sugar. So eating white flour is basically like eating sugar.
You can probably guess what I’m going to say is the healthier type of carbohydrate: the closer to nature complex carbohydrate! Vegetables, fruit and whole grains (such as oats, brown rice, quinoa, barley, etc). Processed carbs such as bread, white flour pasta, and white flour cereal should be a small part of a good diet, and even then try to get as whole grain/closer to nature as possible (i.e. instead of white bread, get whole grain. Instead of apple jacks, eat bran flakes, etc)
Protein is an essential part of our diet. There are proteins that we cannot make in our body. The building blocks of proteins are amino acids which join together with peptide bonds to form proteins.
There are some key phrases when talking about proteins that I want to explain
Essential amino acids: There are 9 a building blocks (amino acids) that our body cannot make. The other amino acids our body can make from other building blocks. But 9 we cannot make so we have to eat.
Complete protein: Has all 9 essential amino acids. Animal products typically are complete, because animals need the same amino acids to build their structures like we do. Plant proteins can be complete or incomplete, as plants don’t need all 9 essential amino acids to build their structure. But you can eat complete plant proteins (this is why soy and quinoa are so popular in plant based diets), or combine different ones to get all 9 essential amino acids. Which brings me to:
Plant based protein: It is a common misconception that you can’t get enough protein from plants. I think this came from the livestock and dairy industry, with messages like “got milk” and “beef it’s what’s for dinner”. In fact, because of this, Americans tend to eat too much protein. For instance: 1 portion of chicken (100 grams) has about 25 grams of protein (about ¼ of protein for the day). Many plant foods have a high amount of protein, for instance 100 grams of sunflower seeds, almonds, or quinoa has about as much protein as chicken. So plant based diets have been labeled as “not enough protein” by the livestock industry. But the real problem is most Americans eat above the recommendation of animal protein a day, almost twice as much required (plus too much animal products is inflammatory and linked with heart disease, cancer, etc. But more on plant based eating later!) My daughter and I eat plant based, and we are doing just fine;)
Fat is needed by every cell in the body for many functions. The building blocks are glycerol and fatty acids which form glycerides (also called lipids).
There are essential fatty acids that we need for structure and functions of the body, but cannot make in our body, so we have to get it by eating it. Fat literally makes up the wall of every cell in the body! Kids especially need fat, since their nervous system and brain are growing, and every cell in the nervous system needs a lot of fat to function. Plus it is a concentrated form of energy (remember 1 gram = 9 calories) so rapidly growing and active children require fat.
Since there are essential fats we have to eat, the lower limit is 15% of diet, but recommended average is around 25% of calories (remember that doesn’t mean ¼ of your plate is olive oil, since it has double the calories it is more like 1/10 of grams of food)
Fat is the most misunderstood macronutrient. It has been blamed for heart disease and obesity, etc, etc. But it was an easy scapegoat (see my last article What is healthy eating?). Now there are different types of fat based on the type of fatty acid. This is probably why fat as a whole has gotten a bad rap, is people think if 1 type is bad, they must all be bad. But doctors use fish oil (omega 3 fatty acids) to treat high fat in the blood, so case in point that all fats are not created equal!
Fat is first broken down into saturated and unsaturated. Chemistry 101: saturated has no double bonds, so is “saturated” with hydrogen. Unsaturated fat has double bonds, so is less saturated with hydrogen. Unsaturated fat is then broken down based on how many double bonds are: monounsaturated (1 double bond) and polyunsaturated (more than 1 double bond). Polyunsaturated is then broken down based on where the double bonds are: omega 6, omega 3, and trans.
A couple key points I want to point out: Omega 3 fat reduces inflammation and is healthier, omega 6 fat tends to be more inflammatory (it is closer to forming inflammation hormones called cytokines). We are supposed to eat more Omega 3 to Omega 6, but unfortunately the standard American diet has 10 times more Omega 6 than Omega 3 (which contributes to the high rate of heart disease, autoimmune disorders, and cancer). Americans need to eat less french fries and more salads with flax oil and walnuts!
Now trans fat is a totally different beast: it is not found naturally, it is made by humans when companies tried to capitalize on the low saturated fat craze, and tried to turn unsaturated fat into saturated fat to spread on toast (aka margarine). We are now learning that the body doesn’t really know what it is, and it causes all kinds of inflammation and problems. So avoid trans fats!
A couple logistics I use this information to do in my household:
For cooking at high heat I use coconut oil.
For cooking at medium heat I use olive oil.
For salad dressing I use olive oil or flax seed oil.
I add whole foods with good fat to my family’s diet: avocados, nuts, fish
Avoid processed foods that use omega 6 oils (there is a chip Boulder brand that uses coconut oil and olive oil)
So now you can see why the mediterranean diet (high in vegetables, fish and olive oil) is the healthiest diet in the world! (Mediterranean diet)
Congratulations, you passed nutrition 101! All this information (and more) is what I used to develop my healthy plate handout.
It’s not about counting calories or grams, but getting the right variety and amount of the right types of whole food. Meals should be modeled from the healthy plate, and snacks should be a plant and a protein.
So just take what you’re doing now, compare it to the healthy plate and healthy snack, and find ways you can modify it to be closer to nature!