Whether you call them breakfast food marathon petrol or diet culture pariah du jour, one thing we all agree on is that people have a strong opinion on carbohydrates. Somewhere along the way, it's almost as if we forgot that "carbohydrates" are just a word we use to talk about certain types of foods. And that these foods actually play a big part in giving our body the energy we need.
To eliminate the confusion of the often malignant always tasty carbohydrate, we're going to cover the basics: what carbohydrates actually are and what they do to your body when you eat them.
What Carbohydrates Are Actually
Technically, carbohydrates are one of the three macronutrients ] (the nutrients we need in large quantities) in our diet along with fat and protein. Carbohydrates are the most important source of energy in the body, according to USA. National Library of Medicine .
Most foods we eat – fruits, grains, legumes, vegetables, nuts, sugar, and dairy products – contain some carbohydrates. The main exceptions would be oils and meat. We measure the amount of carbohydrates present in a food in grams, eg. "This apple has 20 grams of carbs."
If a particular food, unlike fat or protein, has a relatively high carbohydrate content, we call this entire food carbohydrate – eg. "An apple is a carbohydrate." We do the same for fats and proteins: an avocado is "a fat," and a steak is "a protein." (And no, if you ask yourself, butter is not a carbohydrate.)
The Different Types of Carbohydrates
Let's talk about Chemistry 101 for a hot second. The simplest and most basic unit of a carbohydrate is a monosaccharide – a single sugar molecule – made up of carbon, hydrogen and oxygen atoms. These monosaccharide building blocks can be glued together and grouped into different structures of different size, shape and complexity, all of which have specific scientific names that describe how they look at the molecular level. These compositions help to determine how these different molecules taste in our mouth and work in our body.
Unless you spend your days looking at carbohydrates under the microscope Carbohydrates are known to be divided into three main types due to their chemical structure: sugars, starches, and fiber, as described in the USA National Library of Medicine . While something like white sugar consists only of sugar, many foods contain two or three types of carbohydrates.
Sugars are often referred to as simple carbohydrates because their chemical structure is simple and their size is low, Merck Manual . They are in the form of monosaccharides (monosaccharides) or disaccharides (two interconnected sugar molecules), as explained by FDA and are naturally present in fruits, dairy products and sweeteners such as honey or maple syrup.
] Starch and fiber are called complex carbohydrates because they look more complicated and larger under the microscope, as you suspected. They generally consist of long chains of these simple sugars, called polysaccharides (ie, many sugars). Starches are found in foods such as beans, whole grains and some vegetables such as potatoes and corn, while fiber is found in fruits, vegetables, beans, legumes, nuts and seeds as described in the USA . National Library of Medicine .
Why do we even need carbohydrates?
The human body needs all three types of carbohydrate – sugar, starch, and fiber – to function well, according to US. National Library of Medicine because they are all used in different ways by our bodies. (A quick note, if you ask yourself, "Well, what about the keto diet?" Keto is indeed based on the fact that your body has a Plan B when its carbohydrate intake is extremely low: ketosis, a process of transformation However, there are concerns about this type of diet, as SELF has previously reported including the fact that you are lacking all the nutrients in carbohydrate-containing foods, and safety data on fueling your body over ketosis in the long run.)
Now, sugars and starches, generally speaking, are degraded for energy use and storage in our cells, tissues and organs in accordance with US regulations National Library of Medicine . But fiber is oddly carb out: it actually passes through the body mostly undigested, but helps to regulate things like digestion, blood sugar and cholesterol. (Read more about why fibers are so important and how they work here .)
The body, however, resembles a fancy car that uses only diesel fuel. Its preferred form of fuel is a type of monosaccharide or simple sugar, called glucose. "Glucose is like the currency of our body for energy," says Whitney Linsenmeyer, Ph.D., RD, instructor for nutrition and dietetics at Doisy College of Health Sciences, Saint Louis University and spokesman for the Academy of Nutrition and Dietetics, SELF. Fortunately, we do not have to stand around and consume glucose all day because the body is able to convert all of the carbohydrates we eat (except fiber) into glucose during the digestive and metabolic process. It breaks down carbohydrates into smaller and smaller pieces, in ever more specialized steps, until only the easily usable form of energy glucose remains, explains Linsenmeyer.
What happens in your body when you eat carbohydrates?
While all carbohydrates travel the same way from our mouths to their final destination (cells throughout the body), the steps and the time they take to get there depend on the structure of the molecules with which they are They begin.
If you eat sugar – made up of individual sugar molecules or two interconnected sugar molecules – which is already quite close to the body's preferred form of glucose. So there is not much to do. These small sugar molecules can be rapidly digested and absorbed into the bloodstream, making them the fastest form of energy explains Merck Manual . (This is also why they are associated with a rapid rise in blood sugar. – Your body absorbs all the glucose at once.) If you eat starch, it will be in glucose for a longer period of time decomposes time because of its complex structure, explains Linsenmeyer. (That's why this type of carbohydrate provides a slower and more even form of energy and is less likely to cause blood sugar spikes.)
Surprisingly, your body can digest some complex carbohydrates before you even swallow them. "Their saliva produces something called salivary amylase, an enzyme that begins to decompose [starches] as soon as it touches your mouth," says Colleen Tewksbury, Ph.D., MPH, RD, senior research investigator and manager Penn Medicine Bariatric Program and Pennsylvania Academy of Nutrition and Dietetics president, says SELF. (In fact, Tewksbury says, if you let a starchy food like white bread sit on your tongue for a while, it gets sweeter when the salivary amylase begins to turn it into sugar.)
After swallowing these carbohydrates, they become engorged with gastric juices Churning up your stomach containing various acids and enzymes. Then the stomach forwards this appetizing mixture to the small intestine, where the real work of digestion takes place, says Tewksbury. Here, more specialized enzymes and acids are introduced to break them down into even finer parts.
How long digestion takes depends on the type of carbohydrate involved. Simple sugars have the green light to speed up the process just described. If you've eaten sweets or fruit juices from simple sugars, the stomach and intestines are not very busy, so it's very fast. Strengths (and everything else) have to hang around much longer at each point as they break down into smaller and smaller pieces so that the process is gradual.
How the Body Converts Carbohydrates to Energy
As carbohydrates are converted into nice little pieces of glucose, they become ready to enter the bloodstream. Initially, the glucose molecules migrate from the small intestine to the liver via the portal vein, explains Linsenmeyer. The liver then channels most of this glucose through the body through the bloodstream.
Once it enters the bloodstream, some of the glucose is immediately released from the cells in need of energy – for example, in our brains or our muscles – thanks to the vital hormone called insulin. With insulin, the glucose in our bloodstream reaches the body cells and can be used there to generate energy. When we eat carbohydrates, the pancreas automatically excretes the perfect amount of insulin, so that the cells can consume glucose and keep blood sugar levels stable. (Because of this, people with type 1 diabetes who do not produce enough or insufficient insulin to take their pancreas, have to take insulin to keep their blood sugar under control.)
Usually, we consume more carbohydrates than we need at this very moment. Instead of accumulating excess glucose in the blood, the body stores it in several ways.
A small amount of glucose is converted into what is known as glycogen, the special form of readily available "storage glucose" that our body gets stored in our liver and in our muscles as an emergency energy reservoir that we store when needed Linsenmeyer says – for example, if you spend a long time between meals or are traveling a really long time. The rest of the excess glucose is stored in our fat cells as body fat, also with the help of insulin. If we have an energy deficit (ie, consume more calories than we consume) we can access it.
It's worth noting that this is a pretty simplified look at what happens in our bodies when we eat carbohydrates. There are a lot of processes happening when we consume carbohydrates (or any macronutrient), and scientists do not even fully understand them. "Every time we eat, our bodies constantly turn around like 20 different plates [food] to disassemble and utilize them," Tewksbury explains. For example, there are a number of other hormonal secretions that occur when you consume carbohydrates or other foods, but insulin is one of the best known and most useful remedies that you can know about.
The bottom line is that carbohydrates are extremely important – and that our bodies manage to use them for a good cause so we can do things.