An average adult human requires 2,200 kcal of energy per day. Suppose your diet provides an average of 2,300 kcal per day. How many hours per week would you have to walk to burn off the extra calories? Swim? Run? (See Figure 6.4.)
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Verified step by step guidance

1. Step 1: Calculate the excess calories consumed per day. Subtract the required daily energy (2,200 kcal) from the average daily energy intake (2,300 kcal). This gives the excess calories consumed per day.
2. Step 2: Multiply the excess calories per day by 7 to determine the total excess calories consumed per week. This accounts for the 7 days in a week.
3. Step 3: Refer to Figure 6.4 to find the energy expenditure per hour for walking (3 mph), swimming (2 mph), and running (8-9 mph). These values are 245 kcal/hour, 408 kcal/hour, and 979 kcal/hour, respectively.
4. Step 4: Divide the total excess calories per week by the energy expenditure per hour for each activity to calculate the number of hours required per week to burn off the excess calories for walking, swimming, and running.
5. Step 5: Interpret the results to understand how many hours per week you would need to engage in each activity to offset the extra calories consumed. Ensure the calculations align with the data provided in Figure 6.4.

Key Concepts

Caloric Balance

Caloric balance refers to the relationship between the number of calories consumed through diet and the number of calories expended through physical activity and metabolic processes. A positive caloric balance occurs when intake exceeds expenditure, leading to weight gain, while a negative balance results in weight loss. Understanding this concept is crucial for determining how to manage body weight effectively.

Metabolic Equivalent of Task (MET)

The Metabolic Equivalent of Task (MET) is a unit that estimates the energy expenditure of physical activities. One MET is defined as the energy cost of sitting quietly, approximately 1 kcal/kg/hour. Different activities, such as walking, swimming, and running, have varying MET values, which help calculate the calories burned during these exercises based on duration and body weight.

Energy Expenditure Calculation

Energy expenditure calculation involves determining the number of calories burned during physical activities. This can be calculated using the formula: Calories burned = MET value × weight in kg × duration in hours. By applying this formula to different activities, one can estimate how long they need to engage in each activity to burn off excess calories consumed beyond their daily requirement.