There is an absolutely misinformation, about the benefit of eating carbohydrates, thousand of “fitness influencers”, and fanatic followers of atkins, dukan, keto, south beach diet, etc. are following the same strategy of the infamous Nazi Joseph Goebbels "Repeat a lie often enough and it becomes the truth", claiming every day falsely "the secret to losing weight lies in avoiding carbohydrates", these claims are deliberately ignoring decades of scientific-documented studies and confusing us about what carbohydrates actually are.
I always use the analogy of Cocaine to illustrate what carbohydrates really are, we all know cocaine is a stimulant addictive (almost the same effect as the sweets, pastries, soft drinks, junk food, etc.), The main component of cocaine is coca leaf, which paradoxically has been consumed for centuries by my ancestors (in Bolivia), and other Andean countries.
Coca leaf acts as a mild stimulant and helps fight hunger, thirst, pain, and altitude sickness.
Everyday millions of people in south-american highlands chew coca leaves or drink coca tea without experiencing any problems and never become addicted, so what is the factor to turn something helpful in harmful? is the industrial extraction/purification/artificial alteration which includes adding chemicals or removing other natural components. that's exactly happens with the carbohydrates, can be helpful (Natural or complex carbohydrate) or harmful (Refined Carbohydrates)
Natural or Complex Carbohydrates, are basically all food that exists in a relatively natural state or has been minimally processed like whole grains flour, brown rice, brown sugar (we can't just simply cut a piece sugar cane and put it inside our coffee to sweeten it, a minimum process is required to get brown sugar), other examples are all the fruit, vegetables including quinoa, corn, oats, beans, barley, legumes etc, this type of carbohydrates are rich in fibre, vitamins and minerals.
On the other side Refined Carbohydrates are highly processed food, that have been stripped of their original nutrient content and fibre, they come from natural whole foods but they have been altered, processed or refined, in some way or other, for example white flour, white rice white sugar or foods made from these products such cakes, pastries, biscuits,, sweets, sweetened breakfast cereals, cereal bars, energy bar, also fizzy drinks, butter, spread, same fruit juices, milkshakes, chocolate bar, etc.
There is a general consensus between the most important Worldwide Health Organizations to link Refined carbohydrates and highly processed food consumption with the increasing number of people with obesity, type 2 diabetes, cardio respiratory diseases, bowel cancer among others, not one would ever disagree with these facts, that's why the NHS main recommendation is “Carbohydrates should be your body's main source of energy in a healthy, balanced diet. Starchy carbohydrates is an important part of a healthy, balanced diet. It can promote good bowel health, reduce the risk of constipation, and some forms of fibre have been shown to reduce cholesterol levels. research shows diets high in fibre are associated with a lower risk of cardiovascular disease, type 2 diabetes and bowel cancer.