Carbohydrates, commonly referred to as carbs, are one of the three primary macronutrients found in food, alongside proteins and fats. They are the body's main source of energy and are found in a variety of foods, including grains, fruits, vegetables, and dairy products. Carbs are broken down into glucose, which is used by the body's cells for energy. There are two main types of carbs: simple carbs (sugars) and complex carbs (starches and fibers). While simple carbs provide quick energy, complex carbs provide sustained energy and are often found in whole, unprocessed foods.

The belief that carbs make you fat stems from the idea that when you consume more carbs than your body needs for energy, the excess glucose is converted into fat for storage. This can contribute to weight gain if consistently done over time. However, not all carbs are created equal. Refined carbs, such as white bread and sugary snacks, can cause spikes in blood sugar levels and are often linked to weight gain. In contrast, whole, unprocessed carbs can be part of a healthy diet. In the context of losing weight, reducing carb intake can help some individuals control their calorie intake and manage hunger better, which is why low-carb diets are often recommended. However, for building muscle and providing energy for workouts, carbs are essential, and completely eliminating them can be detrimental to physical performance and overall health.