Nutritional Substrate Utilization

Nutritional substrate utilization refers to how the body uses different macronutrients—carbohydrates, fats, and proteins—for energy and other physiological functions. Carbohydrates are typically the body’s primary energy source, while fats are utilized during prolonged periods of low-intensity activity or fasting. Proteins are primarily used for tissue repair and synthesis but can be used for energy in the absence of carbohydrates and fats. The body’s ability to switch between these substrates, known as metabolic flexibility, is important for maintaining energy balance and preventing metabolic diseases. Factors such as diet composition, physical activity, and metabolic health influence substrate utilization, and optimizing this process can support weight management and overall health.