The carbohydrate and fat debate in nutrition
Although the questions around protein intake are still unresolved, today we’re talking about the disputes over carbohydrates and fats.
Exactly the same kind of arguments rage in the diet and nutrition world over carbohydrates versus fats.
In this article I want to explore and explain the questions around carbohydrate and fat intake in light of the different arguments.
The main point of contention is, of course, amounts. What amounts of fat and carbohydrate would actually be healthy, ideal, recommended, and so on. These are the main questions I intend to focus on.
Two (three) schools of thought…
In this debate people generally take one of two positions. There are the so-called “carbohydrate advocates” and the “carbohydrate opponents.” Put simply, some think carbohydrates are “bad,” others think they’re “good.” For the past couple of decades, the forces and views that have dominated hold that “fats are downright bad and carbohydrates are good.”
Several attempts to promote so-called “high-fat” and/or low-carbohydrate diets have been relatively unsuccessful. This is despite the fact that the research evidence does indeed allow us to conclude that, for some individuals (those with low insulin sensitivity), a higher-fat, lower-carbohydrate diet can genuinely be preferable and more beneficial. Still, most dieters believe that carbohydrates = good and fats = bad; they won’t hear of high-fat diets and “flee in terror.”
What’s more, both schools can present credible, telling data to show why their position is the one that works and the only correct one. In real life, though, neither approach works categorically; the truth lies somewhere in between.
You could also name a third category of people (I count myself among them): those who understand that whether carbohydrates or fats are “bad or good” depends largely on context. Which foods are the sources of the carbohydrates or fats, what the proportion of other nutrients is, what the dieter’s goals are, what their genetics are like, and how large and of what kind their daily physical activity is. All of these factors determine and influence what status carbohydrates or fats have, and whether and to what extent they are preferable.
For the sake of clarity and simplicity, it is of course easy to explain and hand out unambiguous recommendations that “X is bad” and/or “Y is evil,” but that isn’t correct and is nowhere near the truth.
To put it simply and tersely, what I’m saying is that there are no “bad foods” and “good foods”; there are “well-constructed diets” and “poorly structured diets.” Depending on the context, a given food may fit very well into one person’s nutrition or menu, while if the circumstances (whatever the factor: energy expenditure, genetics, goals) are different, that same food may have no place on the menu.
What does the body need?
To understand this topic, you need some grasp of human physiology, mainly the part concerning the body’s “carbohydrate needs.” I’ve covered this in my books, but to say it briefly once more: our body actually has no strict requirements when it comes to carbohydrates.
Most body cells can use fatty acids for energy just as directly as they use glucose. There are a few tissues (cells) that can use only glucose for energy. But even these few cells are able to synthesize glucose themselves from lactate.
Against this background, the brain falls into an interesting category of its own. Under normal conditions the brain mostly relies on glucose as well. Although it can’t use fatty acids directly for energy, it can synthesize ketone bodies from fatty acids, and these can then be readily used for energy. For example, after a three-week adaptation period the brain can run almost entirely on energy derived from ketone bodies. The brain needs only up to 25 grams of carbohydrate a day, and the body can produce that amount itself, from pretty much anything: pyruvate, lactate, amino acids or glycerol.
Even the American diabetics’ bible, the RDA handbook (recommended daily allowances of nutrients), states that the daily need for carbohydrates can’t actually be precisely defined or given as a single recommendation. Other serious nutrition books say the same.
Despite these biologically proven facts, many researchers and authors still stress that most (50 – 60% or more) of the daily calories on the menu should come from carbohydrates.
I’ve seen reviews in which researchers acknowledge that, indeed, the body doesn’t actually need carbohydrates in order to function, yet a few paragraphs later they urgently recommend that a good and correct diet should contain at least 50% carbohydrates. Where’s the logic?
At the same time, apart from small amounts of fatty acids (a few grams a day of cod liver oil or other supplements containing essential fatty acids), fats aren’t truly indispensable either. All of the body’s cells are perfectly capable of using glucose to carry out their normal functions (the heart is the exception here: its work and energy supply rely almost entirely on fatty acids). Just as it can with carbohydrates, the body is able to synthesize fatty acids from other substances if the need arises (the human body doesn’t use this energy-production mechanism on a large scale, although it is possible and in some cases does fully occur).
This brings us to the point that, once you set aside that small necessary amount of essential fatty acids, there are no real physiological requirements for fat either.
So what does our body absolutely need, if fats and carbohydrates are practically not required? Besides the basics, such as water and air, the body certainly needs eight essential amino acids, the small amount of essential fatty acids already mentioned, and of course vitamins and minerals. Everything else, to be strictly precise, is optional, conditional and replaceable.
Just in case, let me add that, so that nobody starves to death, we have to supply our body with an adequate amount of calories every day. And since it is unrealistic and unreasonable to try to cover all of your calories with protein, your daily calories have to include carbohydrates and/or fats, or, depending on individual characteristics, a combination of the two in suitable proportions, to meet your energy needs.
As already mentioned above, most of the body’s tissues and cells show very good adaptability and flexibility. Carbohydrates are used when they are “available” and fats when carbohydrates are not “available”. Let us also remember that the body has its own energy reserve, mainly in the form of body fat stored in fat cells. It is tapped into when there are no other nutrients to “take” or “available” for energy.
So why do most people still argue that carbohydrates are “good” and fats are bad?
It’s actually a good question: why has this position been taken, and on what grounds are such diet recommendations actually given? Although I can’t read minds, I think the argument behind this recommendation is very simple: we have to eat something!
As a rule, the proportion and amount of protein to consume are mostly defined and known in menus (although many nutrition specialists are still relatively opposed to larger amounts of protein even today), so the remaining calories have to come from carbohydrates and fats.
Trashing fats, slashing them savagely from menus and panicking about this nutrient all began in the seventies. Fats were cited as the main cause of heart disease, strokes, heart attacks, overweight and so on when consumed in excess. And since people have to eat something, but fats are “bad” and the cause of many ailments, it became, almost by default, the alternative trend that carbohydrates “should be” the preferred and “good” (“better”) choice.
Yet this is merely an unproven trend that took shape over time. The big question is, or should be, whether this tendency really is “better”, more effective and in every case preferable. In science, the status of carbohydrates as the one and only “better” or “good” nutrient has never actually been confirmed!
Author: Janar Rückenberg (translation)
Source:Turg.Fitness.ee
Come and train! ArtGym
