CARBOHYDRATES – Definitions | Types | Sources | RDA | Functions | Deficiency

Most of the foods we eat contain carbohydrates. All fruits and vegetables, all types of bread, cereals and cereal products contain carbohydrates, sugars, and sugary foods.

Yes! You are definitely being familiar with the word Carbohydrates. Probably you know where Carbohydrates are found and what is the primary functions of Carbohydrates.

But do you know which types carbohydrates are good and bad for health? Do you know what is the functions of Carbohydrates except providing energy to the body? If your answer is no, then this article is for you.

Here I will discuss Definitions of Carb, Net carbs, Glycemic Index, Good & Bad Carb, Sources or Examples, RDA, Types or Classifications, Functions and Deficiency Syndrome of Carbohydrates.

Carbohydrate, Carbs, Fab Health Fitness Blog,

★ So, What are Carbs?

First, let me know you about nutrition. In simple language nutrition is food. Nutrition is of two types. Macro & micro.

A macronutrient is a nutrient that required to the body in a large amount. Macronutrients are of three types: Carbohydrates, proteins, and fats.

A micronutrient is a nutrient that required to the body in a small amount. Micronutrients are of two types: Vitamins and Minerals.

So, Carbohydrates or saccharides are biological molecules, that consists of carbon, hydrogen, and oxygen with the ratio of 1:2:1. Carbohydrates are easily available compared to other macronutrients.

★ What are Net Carbs?


Net carbs, fab health fitness

★ What is Glycemic Index? 

Glycemic index is a measurement that tells us how fast this carbohydrate converts into glucose or increase blood glucose level. Two types of foods which have the same amount of carbs can have a different Glycemic index. More the number of GI is more bad for health.

Glycemic Index, GI, Fab Health Fitness

NOTE: A high glycemic index (GI) supposedly means higher blood sugar levels, but plenty of excellent foods, like carrots, have a high GI. New research has found that our focus should be healthy foods, not the GI.

★ Good Carb vs Bad Carb 

Those carbs are slowly absorbed and do not spike blood glucose level, are called GOOD CARB. These are low glycemic carbs.

Those carbs are quickly absorbed and spike blood glucose level are called BAD CARB. These are high glycemic carbs.

Good Carb and Bad Carb, Carbohydrates, Carb, Fab Health Fitness

★ Sources / Examples of Carbohydrates 

Good Carbs:

Vegetables: Dark leafy greens, Onions, Broccoli, Cabbage, Garlic, Tomatoes, Root vegetables like carrots etc.

Fruits: Berries like blueberries, strawberries, blackberries, Tropical fruits like pineapples, mango, Tree fruits like apple, Citrus fruits like orange, lemon, Grapes etc.

Grains / Grain Products: Brown rice, Whole wheat products, Whole grain pasta etc.

Nuts / Seeds: Almonds, Walnuts, Brazil Nuts, Chia seeds, Sesame seeds, Flax Seeds etc.

Legumes: Peanuts, Cashews, Soybeans, Kidney beans etc.

Dairy Products: Whole milk, Cream, Cheese, Butter etc.

Snacks: Pickles, Olives

Bad Carbs: 

Vegetables: Potatoes

Fruits: Dried fruits like raisins, Fruit juice etc.

Grains / Grain Products: White rice, White flour, White bread, Pasta, Corn etc.

Nuts / Seeds: Corn nuts, Honey roasted nuts etc.

Legumes: Sweetened peanut or cashew butter.

Dairy Products: Ice creams, Sweetened yogurt etc.

Snacks: Potato chips, Popcorn, Candy, Cookies etc.

★ Recommended Daily Allowance


National Institute of Health (NIH) recommends you should get 45 to 65 percent of your daily calories from carbohydrates. They also recommend that you should not consume more than 10 percent of simple carbs out of your daily carb intake. 

However diabetic people should not consume more than 200 grams of carbs, while pregnant women should consume at least 175 grams carbs per day.


The National Fiber recommends average man (18-50 years old) should consume 30 to 38 grams per day and average women (18-50 years old) should consume 25 to 30 grams fiber per day. Another recommendation is that each and every person should consume 14 grams of fiber every 1000 calories consumptions. 

★ Types of Carbohydrates 

Carbohydrate is classified based on two different perspectives: Chemical structure & Physiology.

Based on Chemical Structure carbohydrate is of three types.

1. Monosaccharides:

Consists of one sugar or saccharide molecules. So, they cannot be hydrolyzed to smaller one. Eg., glucose, fructose, galactose, ribose, and ribulose.

2. Oligosaccharides:

Consists of two to ten sugar molecules. E.g., sucrose, maltose, lactose, raffinose.

3. Polysaccharides:

Consists of more than ten sugar molecules. E.g., cellulose, pectin, glycogen, inulin, and hyaluronic acid.

Types of Carbohydrates, Carb types, Fab Health Fitness

Based on Physiology carbohydrate is of three types

1. Simple carbs:

Also called sugar or fast-acting carbs. These include Monosaccharides, Disaccharides, and Oligosaccharides. Simple carbohydrates are easily digested because of its simple chemical structure. This is bad for health if it consumed in a large amount because it spikes blood glucose level. Simple carbs are not recommended for diabetic people.

Examples include Candy, soda, table sugar, white rice, white bread etc.

2. Complex carbs:

Also called starch. These include Polysaccharides. Complex carbs take more time to digest and do not spike blood sugar level. And for this reason, complex carbs are good for health.

Examples include brown rice, brown bread, whole wheat bread, sweet potato, refined flour etc.

3. Fibers:

This is non-digestible carbohydrates. Because our body lacks the required enzyme to digest them. Fibers can be soluble or insoluble in water. Soluble fibers easily dissolve in water to form a gel-like substance and fermented by bacteria in the intestine. These bacteria use this gel-like substance as a fuel. Insoluble fibers cannot dissolve in water. Both types of fibers travel throughout the GI tract and give stool a softer and bulkier consistency that’s easier to pass.

NOTE: Unrefined grains like brown rice (complex carbs) contains vitamins and fibers, but these vitamins and fibers are removed during process of white rice (simple carbs) conversion. So, always try to avoid white rice, white bread etc.

★ Functions of Carbohydrates

1. Provides Energy 

The main function of carbohydrates is providing energy in the form of ATP (Adenosine Tri-Phosphate). Dieticians are recommended that about 45-65 % of daily calories should come from carbohydrates. Simple carbs are readymade glucose, so this should be used immediately by the body or it stored as glycogen in liver and muscle. Complex carbs are broken down to glucose and it takes more time compared to simple once. This also should be used by the body or stored as glycogen and some are stored as adipose tissues for future use.

2. Protects proteins from use for energy 

The primary function of the protein is formation and repairing muscle tissues and production of enzymes. Protein also breaks down to glucose when bodies energy need is not fulfilled by the consumed carbohydrates. This happens only when we do not consume sufficient carbs.

3. Essential for fat breakdown 

Oxaloacetic acid, a breakdown product of carbohydrate is required to metabolize fats. Without this fats are converted into ketones, which can toxic for the body. 

4. Helps to Gastrointestinal (GI) function 

Carbohydrates play an important role in GI tract. Lactose helps to grow good bacteria in the small intestine and helps to synthesize certain B-complex vitamin. It also plays an important role in the absorption of calcium. Cellulose provides fiber, which is necessary for foods to move throughout the GI tract and taking waste products of GI tract with it. It also prevents constipation diarrhea and overeating by feeling fuller longer.

5. Detoxification of the body 

Many drugs and toxic wastes are soluble in water, so they easily excreted by urine. But some toxins are insoluble in water and carbohydrates help those toxins to solubilize, so they can easily excrete by Urine.

★ Carbohydrate Deficiency

It is recommended to 45-65% of daily calories should come from carbohydrates. Our body converts them to glucose which is the primary fuel for our body. If we do not consume adequate carbs, following symptoms will appears.

Carbohydrate Deficiency Syndromes, Fab Health Fitness

1. Hypoglycemia:

Due to the lack of adequate carbs, your blood glucose level is significantly dropping. When blood glucose level drops under 70 mg/dL, then that condition is called hypoglycemia. This results in many symptoms like fatigue, dizziness, lethargy, confusion and triggers hunger. It can be resolved by immediate intake of glucose-rich foods.

2. Acidosis and Ketosis:

During carbohydrate starvation, the body shifts glycolysis (breakdown of carbohydrates) to lipolysis (breakdown of lipids) and ketogenesis (breakdown of fatty acids and ketogenic amino acids). This results in the production of ketone bodies. These ketone bodies can increase acidity in blood and cells by changing the pH. Mild ketosis can cause nausea, headache, smelly breath and mental fatigue whereas severe ketosis can cause irreversible cell damage. 

3. Loss of sodium:

Excess ketone in the blood leads to fluid loss and excretion of sodium (Na+) ions from the body. This results in muscle cramps, exhaustion, and dizziness. 

4. Weaken Immune System:

Due to fluid and sodium loss, Vitamin C loss from the body also increased. It may weaken our immune system.

5. Unhealthy Weight Loss:

If carbohydrate deficiency occurs, the body starts the breakdown of fats and muscles for energy needs. But fats takes more time to break compared to muscle. So, body first starts the breakdown of muscle, and due to this, muscle loss or unhealthy weight loss happens.

6. Constipation:

Dietary fibers are necessary to improve bowel movements. Carb deficiency results to diarrhea, constipation and finally recto-colon cancer

7. Mood swing:

Our brain regulates serotonin, a mood regulatory hormone. Due to carb deficiency, our brain may not be able to regulate serotonin. This results in mood swing and depression.

So, now I think you got an overall idea about Carbohydrates. Please tell me how much you like this article. Comment down about you thoughts, doubts, questions and suggestions.

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CARBOHYDRATES – Definitions | Types | Sources | RDA | Functions | Deficiency
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A. R. Choudhury

Hi, This is A. R. Choudhury, a professional blogger & fitness expert from New Delhi, India.

Here at FabHealthFitness, I write about Health, Fitness, Bodybuilding, Supplements and Diet & Nutrition.

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