The word “carbohydrate” is a classification of food that groups together various types of sugar-containing components present in foods.

Carbohydrates are one of the three nutritive components of food that the body needs for energy and to maintain the body's structure and systems (called a macronutrient) which occur naturally in plant foods, including peas and beans, nuts and seeds, grains, dairy and dairy products, fruits, and vegetables.

The other two macronutrients are dietary fats and proteins. 

There are three types of carbohydrates: sugars, starches, and dietary fiber.

Carbohydrates that are less healthy include:

• refined carbohydrates, such as polished rice and flour
• sugar-sweetened beverages, such as sodas and juices
• highly processed snacks, including cookies and pastries

Carbohydrates that are more healthy include:

• fruits, such as bananas, apples, and berries
• nonstarchy vegetables, such as spinach, carrots, and tomatoes
• whole grains, such as whole grain flour, brown rice, and quinoa
• peas and beans, such as black beans, lentil peas, or garbanzo beans
• dairy and dairy products, such as low fat milk, and yogurt

Carbohydrates provide the body with energy and dietary fiber to support good health and healthy bowel function.

Eating to many carbohydrates is can lead to weight gain and an increased risk for chronic diseases, such as heart disease, diabetes, and many more.  Here is a list of the 141 ways that sugar is ruining your health.

Carbohydrates in moderation offer many health benefits when sticking to complex carbs and dietary fiber while staying away from refined and sugar-sweetened beverages.

Also, keep in mind that the ideal diet varies among individuals. That said, as a general recommendation consuming 50–55% of daily calories from carbohydrates vs 65–75%  will help most see lower blood sugar levels .  Carbohydrates are not bad when people manage the amount and types that they consume and tailor these to their specific needs.

The total amount of carbohydrates needed can vary based on activity, but as a general rule of thumb somewhere between 70 and 100 net carbs is the best from a regeneration perspective.  You can subtract the fiber from the total carbs to obtain this number.  It is important to remember that if you are used to eating 300 grams of carbohydrates your goal should be 290.  In other words reduce the amount slowly over time and you will find the right amount for you. 

Here is an article that further expands on this topic (https://www.medicalnewstoday.com/articles/how-bad-are-carbs-really#The-bottom-line)