May 27, 2016

Conscious Kitchen: What are Macronutrients?

Welcome to my new series, "Conscious Kitchen"!

Once weekly, I'll write about a nutrition related topic using information that I've learned in class and on my own. I think this will be a great way for me to get used to communicating about nutrition and a practical way to share information to my family and friends who ask me about nutrition :)

Before we begin, remember to take everything I say with a grain of salt - I'm not yet a registered dietitian, only a nutrition student. I promise to only provide information that I've been taught or that I've read from credible sources, but science is constantly changing too, so information that's "right" one day could potentially be "wrong" the next -- remember that low fat craze in the 80's that medical professionals recommended?

I couldn't sleep last night because I was getting so excited about the different topics that I could write about, from eating on a healthy budget, the reasons to avoid fructose, the raw food diet, omega-3's vs. omega-6's, B vitamins, uses for apple cider vinegar... :) but before I get too far ahead of myself, let's start from the very basics, the fundamentals that I wish I had known when I started investigating nutrition on my own: macronutrients.

What are macronutrients?
Macronutrients are energy-yielding (provide calories) foods needed in gram amounts (g). Three categories fall under the umbrella term "macronutrients": carbohydrates, lipids/fats, proteins.

On the other hand, micronutrients, which include vitamins, minerals, & trace elements, are not energy yielding (do not provide calories) and are needed in microgram amounts (mg).

Why "macronutrients"?
I think it's safe to say that we're all familiar with the food pyramid and the food groups (vegetables/legumes/beans, fruits, grains, meat/fish/eggs/legumes/nuts, dairy/fats, sugar), but thinking about foods in terms of macronutrients is much simpler.

These are the basic building blocks that our bodies require! It's difficult to judge how many "cups" or "tablespoons" of certain foods should be consumed, but when we think about macronutrients and percentages, life just becomes much simpler. Macronutrients are more easily applied to each individual's unique, daily caloric intake too (read the next point!).

Recommendations for Macronutrient Intake:
Here's a very simple breakdown of how macronutrients should compose your total daily calories:

Carbohydrates: 45-65%

Lipids/fats: 20-35%
       -Saturated fats: no more than 10%

Protein: 10-35%

The range that's provided gives each individual the freedom to customize their personal lifestyle choices, taste preferences, dietary restrictions, and unique body responses.

And just as a fun fact:
The POUNDS Lost study (full text here, summary here) was a 2 year long study that compared four different diets of varying macronutrient composition (low fat/average protein, low fat/high protein, high fat/average protein, high fat/high protein) to determine the effect of macronutrient composition on weight loss. The results? Varying macronutrient composition did not significantly influence weight loss.

Why should the greater half of our diet be composed of carbohydrates? With a lot of the low-carb fads/grain-free diets out there, this may seem confusing. Carbohydrates, however, do not only include breads/pastas/rice; carbohydrates are found in vegetables, fruits, legumes, nuts, and dairy too! So those on grain-free, raw, gluten-free diets are still consuming carbohydrates. 

But back to our original question: carbohydrates are the main fuel source for the human body. While fats provide more calories per gram than carbs, carbs are more easily broken down and used as energy. Certain organs, including the brain, prefer to use glucose (the carbohydrate form that most of our consumed carbohydrate foods are broken down into) for energy. Carbs are often great sources of fiber, which is important for slowing digestion and promoting colon health. 

(I'll go into categorization of carbohydrates when I discuss fructose in a future post!)

We mentioned fats when discussing carbohydrates; fats are more energy-dense (provide more calories per gram) but are not as easily broken down and used for energy. However, as there are organs that prefer to use carbohydrates only as energy, there are also organs that prefer to use fats as energy: the heart, liver, and resting muscles. 

There are many different classes of lipids/fats; the only common factor between all fats is that they are "hydrophobic", aka "water-fearing" (think of the oil that's separated from the other ingredients in a salad dressing!). But the fats in our diets generally fall under the "triglycerides" category (the other categories being phospholipids and sterols -- which is where "cholesterol" falls under). 

An easier way to categorize the fats we consume would be saturation. Saturated fats do not contain any double bonds, so all of the atoms in a fat molecule are packed as tightly as possible, often resulting in a solid fat (butter, coconut oil). Monosaturated fats contain one double bond, so they have a little bit more fluidity (olives, nuts, avocados, cheese, eggs, beef). Polyunsaturated fats contain two or more double bonds; sources include nuts, vegetable oils, and fish. 

While some saturated fats are needed, they should not compose more than 10% of our daily calories. 

Why the craze about coconut oil then, if it's a saturated fat? I think I'll have to dedicate another post towards this, because I'll have to go more deeply into "chain length", another way to categorize fats! (I'll link that post here once it's done)

Last but not least, proteins. Proteins are involved in a variety of bodily functions, from serving as enzymes (including the "amylase" in your saliva, which helps to break down starch!) to serving as transporters (like hemoglobin in your red blood cells!). 

Proteins are made of amino acids, and amino acids can be categorized into non-essential, conditionally-essential, and essential groups. What's more important for you to know are the "essential" amino acids; there's no need to memorize this list (though nutrition students have to ;]) though! Just make sure that you are getting complete protein sources. Animal proteins are complete sources (they contain all 9 essential amino acids). Eggs and soy products are complete sources, but beans and nuts are not. (Soy is the only plant based food that's a complete source of protein). 

Something that I'm going to have to research more about on my own is the idea of "complementary proteins". We touched upon this briefly in my class, and you can read this article here about it, but an outdated approach to vegetarianism/veganism is to combine foods to create complete sources of proteins in a meal. (I'll update this post when I feel comfortable/confidant enough to share what I've learned)

Examples of Healthy Macronutrient Sources:
(Remember that many foods are sources of 1+ macronutrients, but some contain higher quantities of one macronutrient over the other)

Carbohydrates: whole grains (brown rice, whole wheat products, oats), potatoes, apples, kidney beans
Fats: avocados, grass-fed butter, olive oil, grass-fed dairy
Proteins: high quality poultry/beef, wild caught fish, almonds, eggs, tofu/tempeh


And I think that concludes our very first "Conscious Kitchen" post!
I sincerely hope I didn't bore you with information; I tried to touch upon the basics and go a little bit more deeply into the more practical aspects, but I'll admit, I can get carried away pretty easily! Please do not hesitate to ask questions in the comments below, and I'm linking a few of my favorite nutrition information sources below for your reference if you're interested in doing more research on your own:

(all time favorite:)

xoxo, han

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