Metabolism: How Does It Do?

Last week we covered the basics of metabolism, including it’s two main categories and what they do.

Wait, you didn’t read that article? Go have a look. We’ll wait…

Okay! Now that we’re all on the same page, here’s your quick review:

  • Metabolism: The sum of all chemical processes in the human body that allow you to Not Die
  • Catabolism: The category of metabolism that breaks down structures in the body, producing waste products, energy, and building blocks for new structures.
  • Anabolism: The category of metabolism that uses the energy and building blocks provided by catabolism to build new structures, such as blood sugars, body fat, and body muscle.

Now, lets talk about what you need for your metabolism to run healthy, long, and strong! (I.e. Not Die)

A Healthy Diet Supports Good Metabolism, or “How to Stuff Your Face The Metabolic Way!”

One of the most influential factors in how your metabolism works is your diet. There are way too many ways that people define “diet” so lets go with something simple:

Diet: The solid or liquid stuff that goes into your mouth, and from there into your stomach, regardless of how nutritious or crappy it is.

Now, based on that definition we can break down your Diet into smaller parts that are actually used by your digestive system to support metabolic activities. The body needs certain things to keep functioning correctly, including essential nutrients like oxygen, carbon, sulfur, nitrogen, phosphorus, hydrogen and about 20 other inorganic elements. You get these from macronutrients, vitamins, minerals, and one very special ingredient. Lets have a look!


The most commonly referenced to parts of food are the macronutrients. This includes Carbohydrates, Proteins, and Fats (lipids). If you’ve ever checked a food label you know how to find them. These are your sources of dietary calories, with each providing a certain amount of energy during their catabolic breakdown. Lets talk about how each one works with your metabolism after being ingested.

Carbohydrates (Carbs)

There are three kinds of Carbs: sugar, starch, and fiber (science calls it “cellulose”). Fiber and sugar are called out on the food label, but starch usually isn’t. Sugar and starch provide the energy associated with Carbs, which equates to 4 calories per gram ingested. Fiber includes anything that the body can’t digest, such as some parts of vegetables (“roughage”), fruits (“pulp”), and whole grains.

Pastas and fruits are particularly high in sugar; potatoes are high in starch. Along with glucose already stored in the body, dietary Carbs make up the first line of energy production in the body. This is good and bad: if you absolutely need a ton of energy right now, then dietary Carbs are awesome. The body will send digested sugars directly to your muscles so they get used first (and quickly). This is why marathoners will “Carb up” before a race, creating an energy glut. Of course, even if you’re not using them, dietary Carbs are still shunted to the muscles, but since they aren’t needed they’re sent to long term storage: body fat!

Fiber is considered a “free” Carb, in that it doesn’t count towards your total for a given day. Since it can’t be digested, you can’t get calories from Fiber. When looking at a food label, you can subtract the grams of Fiber from the grams of total Carbohydrates to find the per serving contents of calorie-providing Carbs. Fiber has been shown to have several benefits, including normalizing bowel movements, helping maintain bowel health, lowering bad cholesterol (LDL) levels, helping control blood sugar levels, and aiding in achieving healthy weight. Fiber is actually pretty awesome; look out for an article about it in the near future!

Too many calories and not enough energy burn each day will equate to fat gain, and the easiest way to get those extra calories is from dietary Carbohydrates. There really isn’t too much controversy here anymore, though there is a great deal of confusion amongst the general populace about it.

Want to know more about dietary carbohydrates? Here’s a past article all about them!

Also, here are links to four good articles going into complementary details: LINK, LINK, LINK, LINK


Ask a body builder what their favorite food is and you’ll probably hear “Protein!” as a frequent reply. Dietary protein comes from sources like eggs, milk, soybeans, meats, vegetables, and grains. Digested protein will provide 4 calories per gram of energy.

Proteins are the main tissue builder in the body, present in every cell. They assist in cell structure, cell function, haemoglobin formation (to carry oxygen), and enzyme activity. They also provide a source of nitrogen, which is used to produce DNA/RNA (ya know, that stuff we’re made of?) and the production of energy.

Proteins are a necessary part of your diet because that’s where we get a fair few amino acids. Amino Acids are part of the proteins that make up muscle and cell tissues, but they also have a huge role in neurotransmitter transport (i.e. your nerves and brain doing what they do) and biosynthesis (i.e. anabolism). There have been about 500 amino acids identified, and the human body can produce most of what it needs as it needs it. The exceptions to this are the Essential Amino Acids, which are so-called because we can’t make them ourselves; they have to be taken in from an outside source. They are:

  • Lysine
  • Tryptophan
  • Methionine
  • Leucine
  • Isoleucine
  • Phenylalanine
  • Valine
  • Threonine

Animal proteins are considered “complete” proteins because they tend to contain all of the Essential Amino Acids in our list, but they can also be high in fat and cholesterol – which isn’t necessarily bad, just something you need to be aware of. Plant proteins can also contain these Essential’s but rarely do you find all of them in one source. Vegetarians and Vegans need to make sure they consume a variety of vegetables, legumes, nuts, seeds, and grains to make sure they get all eight Essentials in their diet.

Hey look, we did an article about dietary Protein too! Check it out.


Dietary Fat has gotten a pretty bad reputation over the last 40 years. From the 1970’s until the early 2000’s the U.S. government dietary guidelines – not to mention tons of fitness professionals, infomercials, and other media sources – have been telling us that Dietary Fat leads to Body Fat. The last 10 years have seen a shift away from that belief thanks to better reporting of diet habits and results, and better communication in general (thanks, Internet!).  Fat does some pretty cool stuff, including: forming cell structure (along with Protein); providing long term, compact energy storage; helping absorb fat-soluble vitamins; and, providing protective/insulating cushion around your organs. Fat has 9 calories per gram, more than double Protein and Carbohydrates.

Fats play a role in the production of Fatty Acids, which can be used for energy just like glucose in skeletal muscle, heart muscle, and the brain. Like the Amino Acids, there are also Essential Fatty Acids which we cannot make in our bodies, but which are required to Not Die. Only two Essential Fatty Acids have been found for humans: alpha-linolenic acid (an omega-3 fatty acid) and linoleic acid (an omega-6 fatty acid). Some others may become Essential under certain conditions, such as disease. Fish, flax seed, and many oils are good sources of the Essential Fatty Acids.

There are three types of Fats:

  • “Saturated Fats” – common in animal-based foods like fatty meats – are considered a bad Fat, and have been linked to higher rates of cardiovascular disease and dyslipidemia (abnormal amount of lipids in the blood).
  • “Unsaturated Fats” – common in avocado, nuts, and vegetable oils – are considered good Fats. The Mono- and Poly- versions have the tendency to lower bad cholesterol (LDL) and are protective against Cardiac dysrhythmia (conditions where the electrical system of the heart goes whacky and beats wrong; yes it can be as bad as it sounds).
  • “Trans Fats” or “Trans-unsaturated Fats” are man made, nasty Fats that will probably kill us all and become the Evil Overlords of All They Survey. That’s actually not too much hyperbole. Trans Fats are very rare in nature and are mainly produced during food processing. They have been shown to raise bad cholesterol, lower good cholesterol, increase risk of coronary heart disease, are not necessary for human metabolism at all, and do not provide any nutritional benefit. You can identify foods containing these one of two ways: they will be called out on the food label (sometimes) or look for ingredients labeled as “partially hydrogenated”. Avoid these. Forever, if possible.

Author’s Note: I’m of the opinion that much of the confusion in the medical/science community is due to poor research, which we’re getting under control. Outside science, I think some of the confusion stems from naming conventions. People see that food contains “Fat” and they know that what they don’t want to be is “Fat” so they equate them to one another, however wrongly. I think a change in jargon (i.e. what we call all this junk) would help. I propose we start saying “Lipids” when we mean Dietary Fat, and we start saying “Adipose” when we mean “Body Fat”.

You can find Dietary Fats in some cuts of red meat, oils, fish, some vegetables, nuts, and legumes.

Sorry, we didn’t do a whole article about fat…Okay. Yes, yes we did.

A Quick Note on Serving Size

When you check food labels for macronutrient breakdown, make sure you look at Serving Size. Some manufacturers get “cute”, listing really low macronutrient contents so their food looks more healthy (“OMG, only 1 gram of fat, 10 grams of carbohydrates, and 50 calories? That’s awesome!”) but you’ll also see that the serving size for the food is ridiculously small (something silly like, “half a cookie”). Realistically, you’re going to be eating more than a single serving in most cases, so be aware that macronutrients contents are additive: 3 servings = triple the carbs/protein/fat/calories! 50 calories per serving is fine until you eat 10 servings.


A Vitamin is, much like an Essential Amino or Fatty Acid, a compound which we need to function but cannot make on our own. By definition this means that the Essentials we already mention are also Vitamins, but by convention they aren’t included in the list of Vitamins required by humans. Also not included are compounds which are like Vitamins (i.e. they promote better health) but which we don’t really need to survive. This leads to the final definition of: an essential compound that is not a Fatty Acid or Amino Acid, which is necessary for good health, and produces symptoms of deficiency when removed from the diet. Currently we have thirteen of these, and in the list below I’ve given their “Vitamin X” designation as well as their “Compound Name”.

  • Vitamin A: Retinol, retinal, and four carotenoids (including beta carotene)
  • Vitamin B1: Thiamine
  • Vitamin B2: Riboflavin
  • Vitamin B3: Niacin, niacinamide
  • Vitamin B5: Pantothenic acid
  • Vitamin B6: Pyridoxine, pyridoxamine, pyridoxal
  • Vitamin B7: Biotin
  • Vitamin B9: Folic acid, folinic acid
  • Vitamin B12: Cyanocobalamin, hydroxycobalamin, methylcobalamin
  • Vitamin C: Ascorbic acid
  • Vitamin D: Cholecalciferol, Ergocalciferol
  • Vitamin E: Tocopherols, tocotrienols
  • Vitamin K: phylloquinone, menaquinones

You get Vitamins from a variety of sources, most commonly foods. You can also buy Vitamin supplements that contain one or more of the Big 13, as I’m sure you’ve seen in many stores. Some others are produced more interestingly: Vitamin K is produced by microorganisms in the intestine, and Vitamin D is produced from ultraviolet light hitting your skin (i.e. sunlight).


These are substances that support the metabolic processes which produce energy, build new structures, etc. While there are over 50 elements present in the body, about 25 have been identified as Essential – and again, this means we need to take them in via diet or some other mechanism. They may also be called Dietary Minerals or Dietary Elements.

The major dietary elements are calcium, phosphorus, potassium, sulfur, sodium, chlorine, and magnesium. Important minor dietary elements include iron, cobalt, copper, zinc, molybdenum, iodine, and selenium.

You get most dietary minerals from food-specific sources (i.e. milk is naturally high in calcium) or from “mineral fortified” versions of foods (i.e. juice that has added calcium. Otherwise, you can also get these from supplements, often packaged as a “complex” along with Vitamins.

Dihydrogen Monoxide

This is a very diverse substance that has a seriously checkered reputation:

  • Also called “hydroxyl acid”, it is the major component of acid rain
  • Contributes heavily to the “greenhouse effect”
  • May cause severe burns
  • Fatal if inhaled
  • Contributes to the erosion of our natural landscape
  • Accelerates corrosion and rusting of many metals
  • May cause electrical failures and decreased effectiveness of automobile brakes
  • Has been found in excised tumors of terminal cancer patients

This stuff is crazy, to be sure…but it’s also called “water”, makes up 70% of the planet and 75-80% of your body, and is totally cool. It supports almost all of your bodily functions in one way or another, so drink it!

Ok, that’s enough science for today! Next week we’ll cover some Life Hacks for boosting and supporting metabolism.