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2.3: Energy Requirements

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    Estimated Energy Requirements

    The Estimated Energy Requirement (EER) is the average dietary energy intake required for growth or maintenance in a healthy individual of a defined age, gender, weight, height, and level of physical activity. Unlike nutrient-specific recommendations, the EER focuses on caloric intake necessary to support basic physiological functions and sustain a healthy body weight.

    EER values vary widely based on life stage and activity level. For example, an active 11-year-old male may require approximately 2,300 calories per day, while a sedentary 11-year-old male might need closer to 1,700 calories per day.

    Activity level EER (~kcal/day)
    Sedentary (little to no exercise) 1,675
    Low Activity (light exercise/sports 1-3 days/ week) 1,920
    Moderately Active (moderate exercise/sports 3-5 days/week) 2,165
    Very Active (hard exercise/sports 6-7 days/ week) 2,650

    Similarly, a 25-year-old female may require approximately 2,500 calories per day, while a sedentary 25-year-old female might need closer to 1,600 calories. Activity level greatly impacts the EER for any individual at any life stage, with even great differences at various tiers of activity levels (Table 2.4). The EER is a useful tool for diet planning, weight management, and public health guidelines. It also plays a foundational role in calculating the AMDRs, as the percentage recommendations for macronutrients are based on total energy needs.

    Use of Energy From Food

    Our bodies rely on the energy from food to power essential processes that keep us alive and functioning. This energy fuels chemical reactions that maintain and repair body tissues, ensuring our cells and organs stay healthy and operate properly. It also supports the electrical conduction of nerve impulses, allowing communication between the brain and body for movement, sensation, and reflexes. In addition, the mechanical work of muscles—whether it's walking, breathing, or even pumping blood— depends on this energy. The body uses energy to produce heat, helping to regulate internal temperature and keep it within a narrow, healthy range despite changes in the external environment.

    Pie chart divided into sections colored red, purple, and gray, representing different data proportions.
    Figure 2.4 Main components of total energy expenditure (TEE) include basal metabolic rate (BMR), activity thermogenesis (AT), and thermic effect of food (TEF). BMR typically accounts for approximately 60% of TEE, while TEF accounts for close to 10%, and AT accounts for 30% (National Academies Press, 2023).

    This page titled 2.3: Energy Requirements was last modified on Wed, 23 Sep 2026 05:36:48 GMT and is shared under a CC BY-NC-SA 4.0 license and was authored, remixed, and/or curated by Heather L. Lehman via source content that was edited to the style and standards of the LibreTexts platform.