Before I started college (when I was young), once I experimented with low carb intake for several days before the basketball match, which I played superbly. Did I discover the secret to success?
Following the same path, for the next two matches, I felt horrible and realized there is no secret. My experiment ended promptly. I had probably just spent the stored glycogen and ran out of energy. Also, basketball (like most other, especially complex, sports) is a sport where many factors influence the performance, and the diet – more specifically, carbohydrates – is just one of them.
Diets are no longer in. Even the diet industry knows that, which is why they now call them lifestyles. One of currently most popular diets... I mean... one of these lifestyles is LCHF (Low Carbohydrate, High Fat).
Like any other popular/alternative diet/way of eating, LCHF is based on exclusion. In this case, minimizing the intake of a whole macronutrient – foods that are based on it (grains, root vegetables, beans, even fruits).
It's impossible to define it precisely because even scientific literature encompasses everything from very low carb intake (5% of total daily calorie intake) up to getting 45% of energy from carbohydrates.
No wonder the results of scientific research about benefits and risks of LCHF diet are very heterogenic.
One of the main arguments of pro-LCHF people is the fact that low carb diet makes the body spend a significantly higher amount of fats than carbohydrates, which supposedly allows for more efficient burning of stored fat (fatty tissue). In other words, it results in more efficient weight loss when compared to non-carb-restricted diet.
The body relies on two main sources of energy – carbohydrates and fats. It primary burns fats as energy when carbohydrates are limited, and when they're available, it burns them. There is no secret. The body has evolved to burn whatever is available to it. This kind of metabolic adaptability has allowed us to survive to his day in the environment with limited access to energy.
This means that the higher the carbohydrate intake, the more energy from carbohydrates we will burn. The higher the fat intake, less energy will be burned from carbs.
This doesn't mean that consuming more fat will reduce the volume of your fat tissue.
If we're not in a calorie deficit, we won't lose the accumulated fat, regardless of diet type and primary source of energy. On the other hand, If we do create a calorie deficit, we will reduce fat tissue regardless of diet type and primary source of energy. A calorie is a calorie.
If it leads to energy imbalance, LCHF is successful. As with every way of dieting, it functions because it makes you (in whatever way) consume less energy than you expend.
LCHF makes the diet less palatabie (tasteful) and monotone as a result of minimizing the entire food group and creates a sense of fullness through higher protein intake. These three reasons are the main explanation of its temporary sucess.
One of the reasons for LCHF popularity is the fact that it causes a fast and significant weight loss at the beggining of the diet. This is due to the fact that the body doesn't have access to carbohydrates from external sources so it burns their storages (glycogen). Since we know that every gram of carbohydrate stored as glycogen in liver and muscles binds 2,5 to 3 grams of water, it's not difficult to explain this quick weight drop.
In other words, at the start of every reduction, especially if carbohydate intake is limited, the initial loss of one to three kilograms occurs due to the reduction in glycogen storage.
Bear in mind that carbohydrates have an energy value of 4 kcal per gram, which means that in order to spend 100 kcal of energy, 25 grams of carbs will be used, and the body will release up to 60-75 grams of water. So burning 100 kcal of energy in this case will result with the number on the scale being 85 to 100 grams less than the initial one.
On the other side, fat has the energy value of 9 kcal per gram and they do not bind a significant amount of water to themselves. So, spending 100 kcal of energy from fats is „worth“ only 11 grams.
This comparison is, of course, simplified, and has other factors to consider, but it points out the state of affairs pretty well.
Glycogen storage in the body is very limited and takes up between 400 grams in a sedentary population and 900 grams in serious athletes. This means that the body in energy deficit will very quickly – generally in a week or two – spend all its glycogen and use as fuel a greater percentage of fat.
This explains the significant weight loss after the beginning of reduction diet. Don't let it amaze or discourage you. This is the way our physical machine works and there is no trick that could change that.
Along with more efficient weight loss, LCHF promises a whole array of health benefits, basing this promise on the thesis that carbohydrates are public enemy number one.
These benefits include putting diabetes type 2 under control, normalizing blood pressure, increasing endurance, mental benefits, and many others.
And while the first two benefits are „stolen“ from general weight loss (they are a consequence of it) and aren't a consequence of reduced carbohydrate intake, the other two, as well as those not listed here, are simply not proven in controlled scientific studies.
Does that mean that LCHF diet has no health benefits?
Depends on what you compare it with.
People have a tendency to group their health habit changes. More specifically, they introduce a whole array of changes instead of just one, changing the whole set of variables, and usually attributing the benefits to only one of them.
Most dietary changes come hand in hand with a change in physical activity. Is the cause of benefits the change in your diet or the introduction physical activity in your life?
Most dietary changes come hand in hand with a reduction in calorie intake. Is the cause of benefits changing your diet or calorie restriction?
Very few LCHF followers switch to it from a balanced diet and optimal body weight. Is the cause of benefits reducing carbohydrate intake, increasing the quality of diet, or reducing body weight?
Precisely because of not knowing and not being able to control a high number of variables, we need to rely on scientists who know and can do that. And controlled scientific research does not point to promised additional health benefits of LCHF diet when compared to an equal quality diet with a more balanced ratio of macronutrients.
Because the intake of entire food groups is limited (grains, fruits, root vegetables, and beans), LCHF diet often lacks fiber, vitamins, and phytonutrients.
Also, limiting carb intake takes away the brain's primary source of energy, glucose. Without glucose, the brain can adjust by using ketones as an energy source, but it's not fully efficient.
Did you notice you get grumpy without carbohydrates when the glycogen levels are low?
Individual experiences aside, science says that low carb diet leads to weaker, or in best case scenario equal cognitive results compared with the diet with higher carb intake. That is exactly the opposite of what the low carb community claims.
One of the problems of the LCHF diet is the high intake of saturated fat, which raises the levels of LDL in the blood and increases the risk of cardiovascular disease.
LCHF, physical activity, and sports
Carbohydrate restriction will probably have a less negative effect if you don't engage in an intense physical activity. However, if you exercise without a sufficient carbohydrate intake, you probably won't be able to achieve a high intensity of activity. Carbohydrates are a primary source of energy in high-intensity activities. This is a consequence of the setup of the human metabolism which cannot produce energy from fat fast enough – like it can from carbohydrates.
Possible consequences of low carbohydrate intake in high-intensity physical activity are also increased cortisol levels (stress hormone with a catabolic function), reduced levels of thyroid hormones, reduced testosterone, and a compromised immune system. And you don't want that.
If you sit for the most part of the day, it's possible that the lack of carbohydrates won't pose a problem. However, if you're an athlete, avoid LCHF. Low carbohydrate intake will have a negative effect on sports performance, especially in high-intensity sports.
I will mention the paleo diet here because it's basically a variant of LCHF. The difference lies in the argumentation of limitations which these two types of diet entail. LCHF limits carbohydrate intake by default, while paleo diet limits it by consequence – foods that our body has supposedly not evolved to ingest (grains, milk, legumes, sugar, coffee, alcohol).
Haven't our ancestors (who supposedly had no chronic diseases) eaten foods with low carbohydrate content?
In an environment where food supply was limited, they ate what they could. Inuit diet in the far north has historically been composed of 80% fish and meat, while Kung nation in the south of Africa ate 70% seeds and nuts.
Furthermore, certain modern traditional societies consume up to 80% of calories from sugar, and they have very low occurrence of chronic diseases.
Does that mean we need to eat large quantities of sugar?
Of course not.
This means that the human body is one extremely adaptable machine and the main reason for modern disease occurrence clearly aren't carbohydrates nor sugar, not even fat, as popular propaganda suggests. These causes are much more complex and we have to admit to ourselves that we don't know them all that well.
In the end, the fact that our ancestors ate in one way tells us nothing about this being justified. Our ancestors killed each other waaaay more than we do. Do we need to accept that habit as well?
When talking about low carb diet, why not try the very low carb one? If reduced carbs are the way to go, cutting them almost alltogether must be even better?
Extreme low carbohydrate diet is called ketogenic diet. Unlike LCHF, which doesn't precisely define the quantity of carbohydrates necessary to achieve it, a ketogenic diet is pretty precise – carbohydrate intake is limited to 20-50 grams per day.
Below this limit, the body enters the state of ketosis, characterized by ketone production from fats and using them as an alternative for carbohydrates.
Promises of the ketogenic diet are similar to those of LCHF.
Even though some might try to convince you otherwise, there is no evidence that ketogenic diet causes increased weight loss when compared to any other diet with equal energy intake. A calorie is a calorie.
Also, there are no evidence that ketogenic diet enhances cognitive (brain) functions.
On the other side, all potentially negative aspects of a „usual“ low carb diet are accentuated in ketogenic diet.
Lethargy, constipation, irregular heart rhythm, bad breath, bad body odour – all possible consequences of ketogenic diet. Sometimes it can lead to nausea, vomiting, and dizziness, sometimes called „keto-flu“.
However, it's interesting to point out that ketogenic diet has its place in treating certain medical conditions, such as epilepsy in children.
LCHF and insulin
Too high levels of any hormone, nutrient, or metabolite will probably have a negative effect on health. This doesn't mean that the levels of abovementioned need to be minimized under the accepted limits – they're neither bad nor unhealthy in itself.
Insulin is a hormone with numerous functions in the body. Among others, it regulates glucose levels in blood, allows for the use of energy from carbohydrates, stimulates protein synthesis (building muscle), inhibits protein catabolism (muscle breakdown), stimulates lipogenesis (storing fat), inhibits lipolysis (fat breakdown). It's also the hormone that makes you feel full.
One of the basic misconceptions about insulin is that it's essential for fat accumulation. It is not. Hormone-sensitive lipase (HSL) is the enzyme responsible for fat metabolism, and insulin inhibits it. But so does fat. Result – even with no carbs, without calorie deficit you won't lose weight.
Another misconception is that minimizing carbohydrate intake will significantly reduce the levels of insulin (if you even needed to do that). Many people don't know that protein intake causes a significant insulin release. So, if you want low levels of insulin (and you shouldn't), eat a low carb low protein diet. I won't be held responsible for the consequences.
The third misconception, of equal importance, is that carbohydrates cause a chronic elevation of insulin levels. These are almost without exception a consequence of obesity and a large quantity of fat depots in the body. The result is the diminished sensitivity of cells to insulin action – creating insulin resistance. In order to compensate for low efficiency of insulin, the body releases more and more of it, and this is what leads to problems.
If you have chronicly high levels of insulin and sugar in your blood, it's certainly recommended to lower them. LCHF is one of the diet ways that works in this regard, and there are some indicationss it does so better than high carbohydrate diet. But considering the difficulties of adhering to this type of diet, as well as potential health risks, I wouldn't recommend it as the first choice.
Insulin is not your enemy. Insulin is not the cause of weight gain.
Enough for today. In the second part of LCHF story I'll write about psychosocial aspect of LCHF, difficulties of adhering to the diet, cheat meals as a consequence of it, anecdotes, and exclusiveness of the LCHF community.