Nutrition trends are about as common as hair and fashion trends...they come and go, depending on how people feel.
For a long while, the biggest trend was low fat diets. Many processed items for sale in supermarkets came out with a non-fat version in support of the trend. The issue with the no fat items was that they replaced the fat with sugar...so it didn’t really help in the long run.
The next trend is the low carb trend diet. Whether it be the infamous Keto diet, or the Atkins diet, brought to the public by the doctor who died of a heart attack, or the Paleo diet...different types of dogmas have emerged from the base of low-carb dieting. Are carbs really that bad?
This is my opinion, and I’ll support it with some of the literature if needed.
My answer is, yes and no.
I believe that moderation is paramount when it comes to carbohydrate consumption. I believe this for two reasons: Firstly, your body has a limited capacity to store carbs in the muscles, and liver. The stored form of carbs is Glycogen. Anything in excess of what your body can store can be converted to fat. However, exercising depletes your carb stores (or rather, your Glycogen stores), making the muscles more glucose sensitive, without having to secrete too much insulin, so you can take in more carbs after a good workout.
Secondly, when the carb sources are not processed, there is fiber in them. Fiber helps create the feeling of satiety and fullness, which means that you end up eating less than you would without the fiber. However, after a workout, it is better to eat carb sources that do not contain fiber, in other words, more sugary sources. This enters the blood stream, and hence your muscles, a lot quicker, allow for the process of energy recover to start sooner than if you had fiber included, which would slow things down.
WHAT ARE CARBS NEEDED FOR?
Carbohydrates are mainly used as a high intensity energy source. They are also the energy source for brain function. Carbohydrates are stored as glycogen in the muscles and liver, and there is enough for about 90 minutes of intense work or exercise. Carbs are also important for their protein sparing effect, meaning that using carbohydrates as an energy source prevents you from using protein (esp. muscle) as an energy source. That way, you actually keep your muscle and possibly build muscle, if combined with progressive resistant training, of course. A downside to eating a mostly carbohydrate meal, especially after working out, can be sleepiness. This is mainly due to the amino acid tryptophan which causes your brain to secrete serotonin (5-hydroxytryptamine), which is a brain neurotransmitter that causes sleepiness and lethargy. If you need to stay awake or alert, a high-carb meal may not be the best choice, especially if you want to stay driven and motivated for a task at hand.
DO YOU NEED CARBS TO FUNCTION?
In essence, carbohydrates are a high functioning fuel, meaning it is mostly used in higher intensity activity, like sprinting and weight training, as well as brain function, whereas fat is more of a low-intensity fuel, used when the activity is low in intensity, like at rest and walking. The question should be rephrased to; do you need Glucose to function? The answer is, yes, you do need glucose to function. Glucose is need for muscle function, and especially brain function. That being said, glucose is easily produced by the breakdown of carbohydrates. However, protein and fat can be broken down into glucose as well, by a process called gluconeogenesis...although this process is somewhat inefficient, and the amount of glucose produced is of a lesser quantity.
CARBS AND MOOD
It’s become common knowledge that dieters can be cranky...walking around hungry all the time, always in a bad mood. This could possibly be in relation to serotonin being released when a high carbohydrate meal is eaten. The tryptophan in the high carb meal causes serotonin to be released (and possibly endorphins), which causes drowsiness, but also causes a good mood. So, conversely, lack of eating carbs causes a drop in blood sugar, which causes tryptophan to decrease, resulting in serotonin to stop being released, which may cause a decrease in good mood.
CARBS AND FAT LOSS
Carbohydrates are insulinogenic, and to a lesser extent, so is protein. That means that when carbs are eaten, insulin is secreted from the beta cells of the pancreases into the bloodstream, in order to drive the glucose into cells, like muscle cells, etc.
Insulin also blocks fat burning (ie: anti-lipolytic), so whenever you eat a carb meal, and insulin is produced, that means that fat burning has stopped. A similar effect may happen if protein is also insulinogenic, so this may be the reasoning behind people following high fat diets, or even intermittent fasting as their diet protocol
CAN KETONE BODIES REPLACE CARBS FOR BRAIN FUNCTION?
Ketone bodies are the result of consuming less than 20% of energy from carbohydrate, especially resulting from the more extreme ketogenic diets. This results in ketosis, where the liver starts oxidizing fatty acids into compounds like 3-hydroxybutyrate, acetoacetate, and acetone (yes, nail polish remover), collectively known as Ketone bodies. The brain prefers glucose as its main source of energy; however, it can metabolize ketone bodies as fuel, if you had low blood sugar, or were in starvation mode. The same is true for muscles and other bodily organs. Another ketone body, called oxaloacetate comes from breakdown of protein, specifically the gluconeogenic amino acids aspartate and asparagines. This means, if you’re going to embark on a low-carb, high fat meal plan, make sure to consume enough protein to allow for maintenance of muscle mass, gluconeogenesis, and fat-burning.
IS BEING FAT ADAPTED A THING?
From the information that is out these on the interwebs on ketogenic dieting, being fat adapted may very well is a thing, although it takes quite a while, at least several weeks, of low carbohydrate eating, in order for your body to start utilizing fat more efficiently for glucose production.
CAN YOU LOSE WEIGHT (BODYFAT) BETTER ON LOW CARB OR LOW FAT DIET?
In my opinion, it can be done on both ways of eating, despite the latter being popular for fat loss. Sometimes, it’s just a question of keeping a slight caloric deficit, and keeping the exercise up, along with patience, and you’ll be good to go.
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Chang, Chen-Kang. “Low-Carbohydrate-High-Fat Diet: Can it Help Exercise Performance?” Journal of Human Kinetics. Retrieved October 20, 2018 from https://www.ncbi.nlm.nih.gov/pubmed/28469746
D, Benton. “Carbohydrate ingestion, blood glucose and mood”. Neuroscience Biobehavioral Review. Retrieved October 21, 2018 from https://www.ncbi.nlm.nih.gov/pubmed/12034132