An important energy source, especially for the brain and high-intensity activity; quality and fibre content matter.
Switzerland age 18–65: 45–60% of energy; free sugars no more than 10%.
Whole grains, potatoes, legumes, fruit, vegetables and dairy; free sugars mainly in sugary drinks and sweets.
There is no classic carbohydrate-deficiency disease if energy, protein, fat, fibre and micronutrients are adequate.
Very low intake can impair training and digestion; refined carbohydrates and free sugars differ from fibre-rich sources.
No specific skin, hair or nail signs.
Quality problems arise more from high free sugars and low fibre than from carbohydrate as a category.
Consider the whole dietary pattern, fibre, activity, glucose and individual tolerance.
Usually no supplement is needed; carbohydrate drinks/gels are situational sports nutrition.
High free-sugar intake promotes dental caries and can contribute to energy excess.