Every few years, a new dietary fad hits the fitness scene. Unfortunately, it doesn’t take long for people to start following such trends. Shortly after, people start glorifying those new dietary fads as if they are the end all be all to nutrition programs. Not so fast! The most recent dietary fad to hit the market was the low-carb dogma. Not entirely sure where this belief originated, but it has spread around the web faster than the speed of light – not literally -. According to carb-haters, carbs are the worst thing you can consume if your sole goal is to stay lean and mean. In fact, other crowds take it a step further and swear that carbs are bad for your health and that our “ancestors” didn’t really eat carbs. I call horseshit. Not only because unnecessary dietary restrictions are stupid, but also because carbs have been unfairly demonized. Many of the negative ideas associated with carbohydrates are not based on any scientific facts whatsoever. Moreover, low-carb diets have done significantly more harm than benefit. Keto? Paleo? Atkins? Intermittent fasting? You name it, it’s just another fad. Let’s bust a few myths surrounding carbohydrates.
Myth #1- Carbs make you fat
No. You know what makes you fat? Eating significantly more than what your body needs. Try consuming 1000 calories above maintenance and I promise you that most will be stored as fat, regardless if those calories come from carbs, protein, or dietary fat. The general consensus behind carbs making you fat is how, allegedly, they are processed and absorbed. Carbs are our bodies’ first source of fuel. It’s the most efficient source of fuel and is always readily available, given that you are eating adequate amounts. The logic behind carbs being stored as fat is that if you consume carbs (fuel/energy) and don’t use that energy (burn it through activity) then they will be stored as fat for later use. While this may seem logical on paper, as we all know already, the human body is much more complex than a simple in-and-out equation. Take a look at this simple flowchart:
So, what exactly happens post carbs consumption? The general process – I left out a few irrelevant details- is illustrated in the above diagram. There are two main problems with carb haters’ logic: 1) It leaves out conversion of excess carbohydrates into glycogen to be used between meals. 2) Presence or absence of a caloric surplus, which will automatically affect availability of energy as well as carbohydrates amount consumed.
The flawed logic behind carbohydrates intake and digestion would simply look like this:
Carb intake > Mechanical and chemical digestion > Conversion into glucose > Carbs move into small…blood. > Pancreas secretes insulin…cells. > Cells uptake glucose…activities. (mainly to produce energy) > Excess glucose that cells don’t need is converted into triglycerides and stored as fat.
Fortunately, this isn’t how things are. Had things been that way, we would’ve all been a bunch of fat slobs. Just like carbs are the body’s main source of energy, glycogen is its second source of energy.
What is glycogen?
Glycogen, by definition, is a polysaccharide that can be easily converted into glucose through hydrolysis. Glycogen is majorly stored in muscles with a little bit stored in the liver. During short periods of no energy intake, the body breaks down glycogen into glucose to be utilized as energy within cells. Thus, it’s a secondary source of fuel. However, the body can only store about 400 grams of glycogen at a time, which makes it an inefficient source of energy during prolonged periods of little to no food intake. On the other hand, fat, or, adipose tissue, is a much more efficient energy source and can save our lives during times of famine. Each gram of stored glycogen makes you store 3-4 grams of water along with it.
How does this relate to our topic of discussion?
This relates to our topic of discussion because it illustrates that it’s not really that easy for our bodies to convert carbs into triglycerides and store them as fat. Additionally, that flawed way of thinking neglects a few more critical points.
1) The brain and muscles prefer carbs as an energy source
Due to the ease of creating energy from carbs, our brains and muscles prefer carbs as an energy source over any other fuel sources (fat and triglycerides, for example). In fact, carbs are essential for the production of many important hormones and neurotransmitters such as serotonin and dopamine. In fact, serotonin can be made only upon consumption of sweet and/or starchy carbs. Why? Because tryptophan, the building block of serotonin, can only pass the blood-brain barrier at sufficient amounts when carbs are consumed. Tryptophan is an amino acid that can be found in dairy and meat. The problem with tryptophan passing the blood-brain barrier is that when we consume protein, which is full of many other amino acids, tryptophan and other amino acids compete to get into the brain. Thus, protein blunts the efficient uptake of tryptophan into the brain. Serotonin is involved with mood regulation, depression (lack of serotonin and/or dopamine), metabolism, cortisol, testosterone production (think how depression affects testosterone levels), and weight loss. I am using the term “carbs” loosely here; however, what I am truly referring to is glucose.
Ever wondered why we all – not just women – crave starchy carbs, junk food and sweet treats when we are stressed or sad? Yup, that’s the serotonin-carbohydrates link talking. Simply put, during those periods of stress/sadness, serotonin levels are most likely low, and what can elevate serotonin better than some delicious carbs or comforts foods? Nothing really. This is the body’s natural defense mechanism against depression and periods of stress. If you still can’t see the link between serotonin and weight/fat loss and muscle building, just think about how low levels of serotonin can affect your other hormones. Low levels of serotonin and/or dopamine (periods of stress/depression) will put us in survival mode. As a result, cortisol levels will chronically rise, which will in turn result in excess storage of body fat. This is because the body thinks it’s in survival mode and assumes there is critical lack of food. Your body can’t differentiate between you being depressed because your favorite TV show just ended and you not having access to food. Moreover, testosterone levels will significantly decrease, a double-whammy for excess fat storage and hindered recovery. Other hormones will usually go off-balance as well, resulting in a recipe for disaster. Therefore, many people find it difficult to lose fat and gain muscle during periods of extreme stress/sadness. Every felt terrible during periods of low-carb intake? Now, you know why.
Thus, contrary to widespread belief, carbs can help you lose more fat and build muscle faster by optimizing serotonin levels and thus, indirectly, ensuring optimal levels of other hormones.
NOTE: During periods of low-carb intake, the brain feeds off ketone bodies which are produced during a physiological state known as dietary ketosis. Even though ketone bodies are glucose-sparing within the brain, our brains still prefer glucose as their main source of energy.
2) TEF – Thermic effect of food
As discussed before, TEF, or, thermic effect of food, refers to the caloric cost/price of processing and digesting different macronutrients. Meaning, how many calories a body burns during digestion of carbs, protein, and fat. Protein has the highest thermic effect, which is between 20% and 35%. Carbs and dietary fats burn between 5% and 15% of energy consumed. Realistically, the ratio is closer to 10-15%. This also depends on whether your diet is majorly composed of simple processed carbs or complex carbs and dietary fiber.
If you look at the first diagram in this article, you’ll see that carbs go through an extensive process before they’re converted into energy. It’s not just a matter of “I just ate a piece of bread, now I am ready to go!” Given that carbs’ TEF is approximately 10% of amount consumed, we will always end up with LESS energy than we consumed. For example, if a person consumes 100 grams of complex carbs and/or fiber, this means that our person in question has just consumed 400 calories given that each grams of carbs contains 4 calories. However, post digestion, assuming a thermic effect of 15%, this person’s body will have burned 60 calories just through digestion! Thus, our person in question ends up with only 340 calories. Some will be utilized as energy and the rest will be stored as glycogen as explained earlier. In essence, you’ll always end up with less energy than what you consumed.
3) Caloric intake
As mentioned a dozen times before, how many calories you consume dictates weight loss or gain. There is no way around it. But, unfortunately, people still believe that carbs alone dictate whether you’ll gain or lose weight. Not so fast! Remember the caloric intake equation?
Caloric surplus = consuming MORE calories than your body needs = weight gain.
Caloric deficit = consuming LESS calories than your body needs = weight loss.
Caloric equilibrium = consuming as many calories as your body needs = no change in weight.
NOTE: I am using the term “weight” loosely here. Body composition is a different story.
How does this relate to carbs making you fat or not?
Hypothetically speaking, if one’s diet is solely composed of carbs but he is in a caloric deficit, his body will still have LESS energy than he really needs. So, regardless of how much carbs he is consuming, his body will still have to tap into stored body fat to compensate for the lack of energy available. The result is fat/weight loss. No and’s, if’s, or but’s. This is because although our hypothetical person is solely consuming the body’s primary source of energy, his carb intake still can’t provide the amount of energy his body requires to carry out its functions. This person’s body will keep processing carbs and creating and breaking down glycogen to meet his energy requirements. By the end of the day, he’ll have burnt all the energy he consumed and some from his stored body fat. Keep in mind that this extreme example is not even realistic. No one solely consumes carbs or any other single macronutrient. It doesn’t happen. And doing so will result in sub-optimal health and all kinds of hormonal imbalances. Oh, and don’t forget “TEF”.
Myth #2 – Low carbs = Fat Loss
This was previously covered in the “Top 5 Fat Loss Myths” series. More specifically, I covered this same topic in the fourth segment of the series, “Fat Loss Myth #4: You Must Eat No Carbs!”. So, I won’t re-write everything that I already covered. However, I’d like to add one more thing to this topic.
The logic behind carbs blunting fat loss is the fact that carbs result in secretion of insulin, the storage hormone. As discussed in that article, this is a myth. Insulin is secreted in response to any macronutrient consumption, however, simple carbs produce the highest and quickest spike in blood glucose levels. So, whatever you eat, your pancreas will secrete insulin to remove nutrients from the bloodstream and into body cells.
Besides everything discussed in that article, there is one more thing to be mentioned; glycogen utilization and depletion.
I mentioned that glycogen is our bodies’ second energy source after glucose, remember? Good. For our bodies to tap into stored body fat and use it as energy, glycogen levels within muscles and liver must be depleted. Thus, the human body’s energy sources are as follows – in chronological order -:
2- Stored glycogen.
3- “Precious” body fat.
Why does the human body resort to body fat as an energy source last? Because it’s the most efficient. Body fat can be stored forever and contains significantly more energy. Moreover, it can be stored in excess amounts as opposed to glycogen, of which only 400 grams can be stored. This ensures survival.
Thus, logically, avoiding carbs will guarantee absence of glucose, which will make the body tap into its second line of defense, glycogen. But, glycogen isn’t an efficient source of energy and will be depleted quickly, thus the body will eventually resort to stored body fat for energy. Right? Yes and no. The general idea is correct in that the first 2 energy sources must be depleted first before our bodies can utilize stored body fat, but it doesn’t give us the whole picture.
If you think consuming low carbs will yield better results because it allows the body to tap into body fat quicker, think again. Every heard of gluconeogenesis? I’ll discuss this in the next point, but keep it in mind for now.
Once again, a caloric deficit will yield fat loss whether you’re consuming carbs or not. Considering the above illustration, let’s see how this relates to your level of energy intake.
A caloric deficit will yield intake of less energy than the body requires. This means that the body will have LESS energy (glucose) than it needs. So, what will happen next? The body will break down glycogen that was stored the last time you consumed an abundance of energy. The excess was stored as glycogen, right? But, due to glycogen not being an efficient energy source, glycogen storage (in the liver) will be depleted rapidly and the body will eventually resort to stored body fat. TADA! You have successfully induced lipolysis – breaking down of body fat -. Which means you will lose body fat.
“But, if I eat enough carbs, my body won’t run out of its 2 first energy sources and my body won’t have to burn stored body fat despite being in a caloric deficit, right?”
The answer to the question above is: NO! You are missing a very important point: a caloric deficit will put you in a constant state of negative energy balance, which means you won’t have enough glucose to create energy to use for bodily functions and extra activity and thus your glycogen storage will be depleted through the entire time of being in a caloric deficit. Or, more specifically, very little glycogen. Thus, your body will constantly have to tap into stored body fat to offset the caloric deficit. Simple, right? I thought so. Which is why everyone who starts a diet plan will often lose a 3-5 pounds in the first week and feel ecstatic. Relax, that’s just your body depleting stored glycogen and water. True fat loss occurs after the first week of being in a caloric deficit. Moreover, complete glycogen depletion is not necessary for lipolysis to occur.
Myth #3 – Carbs are not “essential”
If someone gave me a dollar each time I saw or heard this phrase, I’d be a millionaire. I have seen this phrase thrown around so many times that I felt the need to illustrate some deeply-woven misconception/deception here.
Before anyone jumps at me, yes, carbs are not essential for human survival. HOWEVER, glucose is! I bet your personal trainer didn’t tell you that. Moreover, carbs are crucial for optimal function of many bodily processes. My main goal is to illustrate that glucose is essential for human survival. At any given moment, there is a bit of glucose circulating in your bloodstream to be utilized as energy. Go long enough without eating and you’ll most likely experience hypoglycemia, or, low blood sugar levels. As I mentioned earlier, the brain, heart, and muscles prefer carbs over any other macronutrient because it can be converted into glucose much easier. Moreover, glucose is the body’s primary energy source. So, what happens during periods of no carb intake?
Gluconeogenesis is the process by which our bodies create glucose from non-carb sources. If you solely consume protein, your body will convert some of it (excess) into glucose, or, “carbs”. If you consume only protein and dietary fat, your body will create glucose from some of the consumed protein and dietary fat. Thus, despite removing carbohydrates from your diet, your body will still create glucose to use as energy! In other words, your body will “make carbs” whether you like it or not. That’s because glucose is essential for energy production (ATP). Had glucose not been essential, our bodies wouldn’t have evolved to create it from non-carb sources.
Simply put, you may be consuming low carbs, but you will still be in a state of “adequate carb/glucose intake” to allow for adequate blood glucose levels. Otherwise, hypoglycemia incurs and energy production suffers. Your body will create as much glucose as it needs to carry out its functions properly. Oh, I almost forgot, when your body taps into stored body fat and converts it into “energy”, it simply means that stored body fat was converted into glucose to be shuttled away to cells and utilized as energy. Take that, carb-haters! One might raise the argument of body ketones and fat being glucose-sparing. While this may be true, some tissues still require glucose.
NOTE: Gluconeogenesis has been shown to increase energy expenditure. This is because gluconeogenesis is a somewhat energy-demanding process. Thus, low-carb diets can increase energy expenditure slightly. However, differences in fat loss won’t be significant, if any. In fact, it can hinder fat loss by putting you in a larger caloric deficit and by breaking down protein and converting it into glucose instead of using it to spare muscle mass. Gluconeogenesis is anabolic in the sense that it creates glucose, but it’s also catabolic because it requires the breakdown of amino acids and/body fat to create glucose. However, if your diet is up-to-par, and you are consuming enough protein, you should be able to keep your hard-earned muscles.
Important: Just because a macronutrient isn’t essential for survival, doesn’t mean it can’t and won’t improve health. You won’t die from not eating carbohydrates, but your body composition, performance, and most importantly, your health, will suffer.
To Be Continued…
If this article wasn’t enough to convince you that low-carb diets are nothing but mere crap, hold on tight, because there will be a second article to bury this low-carb fad once and for all. Low-carb diets will not yield superior fat loss vs. any other diet that implements a caloric deficit. In fact, a moderate-high carb diet will almost always yield more fat loss than a low-carb diet. Moreover, an inadequate intake of carbs will yield sub-optimal health, performance and body composition changes. In the next article, I will cover how low-carb diets have caused significant public harm, some hormonal interactions, and other goodies. Stay tuned!