Final answer:
To estimate a person's energy needs quickly, you multiply their body weight by an appropriate factor based on their activity level and medical condition.
Step-by-step explanation:
A quick way to estimate a person's energy needs is to multiply body weight by a factor appropriate for the person's activity level and medical condition. For instance, to calculate the energy needs for a moderate medical student who weighs 55 kg and does 8 hours of moderate work, we add 100 kcal per hour for the activity to the person's basal metabolic rate (BMR). Since different factors like body composition, age, gender, and level of physical activity can influence calorie needs, this is a simplified method that can serve as a starting point for more individualized nutritional planning.