Everything you ever wanted to know about carbohydrates!

Carbohydrates—love them or hate them, but choose them wisely.

They are one of the main nutrients, an important source of energy and a main component of the diet of the majority of people. It is extremely difficult to avoid them unless you are an Eskimo and eat mostly meat! They are present in grains, legumes, vegetables, and fruit. The low-fat diets advertised in the 60s encouraged people to avoid fats and eat carbohydrates lavishly. Nowadays, the trends have changed, and more of us turn away from potatoes, breads, and pastries. Carbohydrates are a healthy and beneficial compound of the diet only when they have a low GI and GL.

What are carbohydrates?

Carbohydrates provide energy to power the central nervous system and movement (energy for muscles), and they enable fat metabolism. Carbohydrates are the preferred source of energy for biologic work, which means they are used first. Other nutrients, such as proteins, which are normally building blocks for muscles, can also be used as an energy source if there are no other sources of energy.

Carbohydrates can be divided into simple and complex.

Simple carbohydrates include sucrose (present in chocolate) and lactose (present in milk). They are broken down and absorbed fast, and therefore they rapidly increase the levels of sugar and insulin in the blood.

Complex carbohydrates include starches (bread, pasta) and dietary fiber (whole grain, vegetables), and have larger molecules. Digestion takes longer than in the case of simple carbohydrates, and it causes a slow and steady increase in blood sugar and insulin levels. Therefore, the energy lasts longer.

Dietary fiber belongs to the group of carbohydrates; it is the indigestible but edible part of plants. Dietary fiber can be soluble or insoluble in water. Soluble fiber can be dissolved in water and absorbed, providing relatively little energy. It is present in fruit and vegetables, especially green leafy vegetables, celery, and apples. Insoluble fiber cannot dissolve in water and does not provide energy. It is present in whole grain products. Its most important task in our organism is promoting gut motility and satiety.

Non-starch polysaccharides also belong to a group of dietary fiber. They are large molecules and cannot be digested. Some of them are fermented in the large intestine. While simple carbohydrates have up to two units of sugar, complex ones have three or more, and polysaccharides have more than 10 units of sugar.

Sources of carbohydrates:

Depending on the type of food, the content of carbohydrates, sugar, and fiber may differ. The best sources of simple carbohydrates include table sugar, honey, fruit, maple syrup, and milk. The best sources of complex carbohydrates include all whole plant foods, such as green vegetables, whole grains, whole grain products such as cereals, pasta, breads, beans, peas and lentils, and starchy vegetables. The best sources of fiber are vegetables, fruits, and whole grains. The best sources of non-starch polysaccharides are fruits, vegetables, legumes and nuts, oats, guar gum, and psyllium husk.

What are the recommendations?

According to our previous article on a balanced diet, which you can find here, the daily amount of total carbohydrates recommended by the WHO should constitute between 55 and 75% of total daily energy. This range is wide, as the priority in our food consumption is proteins and fat. Therefore, carbohydrates should be adjusted as the remaining percentage after the rest of the nutrients.

The percentage range of 55 and 75% of carbohydrates falls between 275 and 375 grams of carbohydrates per day for a 2,000-calorie diet (between 344 and 469 gram of carbohydrates per day for a 2,500-calorie diet).

Scientific proof against high-carbohydrate diets

There is more and more scientific proof suggesting that restricting carbohydrate consumption not only is the best treatment for obesity, but also can prevent or even treat some chronic diseases such as diabetes. Low-carbohydrate diets (low-carb diets for short) are regimens where carbohydrates are restricted to less than 45%. They recommend limiting foods high in easily digestible carbohydrates such as bread, pastas, and pastries, and eating more foods low in carbohydrates like salads, vegetables, and some fruits, together with foods rich in proteins and fats, such as meat, fish, eggs, cheese, and nuts.

The increase in consumption of highly refined carbohydrates (such as in breads, cakes, and ready-to-eat meals) in recent years contributed greatly to increased numbers of metabolic disease and type 2 diabetes.

A bit of dietary history

The idea of eating a diet low in carbohydrates is very old. Followers of the Paleo diet, which is believed to have been practiced by early humans, claim that we are genetically adapted to low-carb diets. Closer to our times, there were many dietitians who recommended restraining from foods high in carbohydrates. These were Richard Mackarness (author of “Eat Fat and Grow Slim”), Irwin Stillman (author of “The Doctor’s Quick Weight Loss Diet”), Wolfgang Lutz (author of “Life Without Bread”), Robert Atkins (author of “Dr. Atkins Diet Revolution”), and David Jenkins and Michel Montignac, who focused more on the concept of glycemic indexes.

Is there any difference between low-carb and low GI diets?

In general, low-carb diets eliminate almost all carbohydrates. While elimination of sweets, starchy vegetables, and breads is beneficial, whole grains and legumes should remain in the diet due to their nutrients. Only small amounts of certain fruits, vegetables, and whole grains are allowed.

A low-GI diet is based on the effect that certain food has on blood sugar and insulin levels. Various carbohydrates have different GIs, and those with the highest number (e.g., white bread, noodles, rice, sugar, and beer) are restricted. However, there are many whole grains, legumes, and vegetables that have moderate GIs and can be eaten under certain conditions. Applying some preparation tricks, which are described here, can even further lower GI.

Overall, the low-GI diet is more varied, as it allows many low-GI carbohydrates. It’s also more suitable for vegetarians and vegans, as there are more food choices.

Fortunately, both diets allow eating enough not to be hungry. Additionally, both of them can be used as temporary regimens to lose weight and as long-term eating habits to maintain weigh loss. Apart from a positive influence on weight, they also contribute to lowering blood sugar, blood pressure, and triglycerides.

How many carbohydrates should we eat to benefit the most from our nutrition?

Unfortunately, there is no one golden rule here; all depends on our age, activity, health and life style. Those who are very athletic and have developed muscles will need more carbohydrates than others who prefer a more sedentary way of living.

It is good to calculate how many carbohydrates you are eating now (some tips for this calculation you will find at the end of this article). It will give you some idea about where you are. Most people consume way above 350 grams of carbohydrates per day.

If you want to eat a low-carb diet, you should lower your daily carbohydrate consumption to below 45% of your daily calorific intake.

Carbohydrate consumption between 20 and 45% of total caloric intake

For those who eat a 2,000-calorie diet, this amount of carbohydrates will mean between 100 and 225 grams per day. It is a moderate amount and will mean eating plenty of green vegetables, some fruits, and one meal with whole grains and legumes. Such a diet will be healthy, and you will benefit by losing weight at a very slow pace.

Carbohydrate consumption below 20% of total caloric intake

Such a diet will be more demanding and more efficient for losing weight. It will mean that you cannot eat more than 100 grams of carbohydrates per day (for a 2,000-calorie diet), and that might be a challenge. It will definitely be tough for vegetarians and vegans. You should stick to veggies, one serving of fruit, and one serving of whole grains and legumes—but only those with a low carbohydrate content.

Carbohydrate consumption below 10% of total calorific intake

This is a quick weight-loss diet that will definitely work for most. Since it will be just 50g of carbohydrates per day (for a 2,000-calorie diet), you will be limited to low-carb veggies, berry-type fruits only, and one serving of whole grains.

How to calculate your daily carbohydrate intake

First, make a list of what you eat.

If you want to be precise, you need to get a kitchen scale.

It should be straight forward and easy with the products you eat every day (e.g., bread for breakfast or a bowl of cereal), as you will have to measure the amount only once.

Check the nutritional values on the package or box. Calculate your intake in the following way:

(Mass of your portion/Serving size)*Amount of carbohydrates

If the product you eat has no nutrition label, go to the USDA nutrient database

(http://ndb.nal.usda.gov/)

and find a product most similar to the one you eat. This database gives values per 100g or other convenient units like cups, slices, or pieces. Make sure to enter a proper amount and put down the value for carbohydrates.

Continue with all other products you eat. If you go to a bar or restaurant, take notes on your meal and then find it in the above-mentioned database. It will be just an estimate, but it’s better than nothing.

Remember that this is to calculate your carbohydrates. However, many foods contain sugars together with carbohydrates (e.g., pasta, veggies, breads, etc.). Count that too and check how close you are to the recommendation here.

 

Source: http://www.who.int/nutrition/topics/5_population_nutrient/en/

http://ndb.nal.usda.gov/

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