Your friend, Suki, asks you for advice about her weight. She wants to see if she is in a healthy weight range for her size and age. She is currently 150 pounds, 5’3” tall, and 40 years old. She also wants to know how many calories she should eat each day to stay at her current weight. Help Suki by explaining height and weight measurement for all age groups. Use the body mass index (BMI) graph to determine Suki’s BMI. Calculate Suki’s daily required caloric intake to maintain her current weight.

1 answer

To help Suki determine if she is in a healthy weight range for her size and age, we can first calculate her Body Mass Index (BMI) and then discuss her daily caloric intake needs.

Step 1: Calculate Suki's BMI

The formula for calculating BMI is:

\[ \text{BMI} = \frac{\text{weight in pounds}}{(\text{height in inches})^2} \times 703 \]

  1. Weight: Suki's weight is 150 pounds.

  2. Height: Suki's height is 5 feet 3 inches. To convert this into inches:

    • 5 feet = 5 × 12 = 60 inches
    • Plus 3 inches = 60 + 3 = 63 inches

Now we plug in the values:

\[ \text{BMI} = \frac{150}{(63)^2} \times 703 \]

Calculating \( (63)^2 \):

\[ (63)^2 = 3969 \]

Now, substituting back:

\[ \text{BMI} = \frac{150}{3969} \times 703 \approx 26.7 \]

Step 2: Interpretation of BMI

According to the CDC classification, BMI categories are as follows:

  • Underweight: BMI less than 18.5
  • Normal weight: BMI 18.5 to 24.9
  • Overweight: BMI 25 to 29.9
  • Obesity: BMI 30 or greater

With a BMI of approximately 26.7, Suki falls into the overweight category. She should discuss her weight with a healthcare professional for personalized advice and potential weight management strategies.

Step 3: Estimated Daily Caloric Intake

To maintain her current weight, we can estimate Suki's daily caloric needs using the Mifflin-St Jeor equation, which considers age, gender, height, and weight. However, since her gender is not specified, I'll provide the equation for both male and female:

  • Mifflin-St Jeor Equation (Men):

    \[ \text{BMR} = 10 \times \text{weight (kg)} + 6.25 \times \text{height (cm)} - 5 \times \text{age (years)} + 5 \]

  • Mifflin-St Jeor Equation (Women):

    \[ \text{BMR} = 10 \times \text{weight (kg)} + 6.25 \times \text{height (cm)} - 5 \times \text{age (years)} - 161 \]

Convert Suki's weight and height:

  1. Weight in kg: 150 pounds / 2.205 = approximately 68.18 kg
  2. Height in cm: 63 inches × 2.54 = approximately 160 cm

Using the equation for women:

\[ \text{BMR} = 10 \times 68.18 + 6.25 \times 160 - 5 \times 40 - 161 \]

Calculating:

  1. \( 10 \times 68.18 = 681.8 \)
  2. \( 6.25 \times 160 = 1000 \)
  3. \( 5 \times 40 = 200 \)

So,

\[ \text{BMR} = 681.8 + 1000 - 200 - 161 = 1320.8 \]

Next, we need to multiply the BMR by an activity factor to determine total daily caloric needs. Common multipliers are:

  • Sedentary (little or no exercise): BMR × 1.2
  • Lightly active (light exercise/sports 1-3 days a week): BMR × 1.375
  • Moderately active (moderate exercise/sports 3-5 days a week): BMR × 1.55
  • Very active (hard exercise/sports 6-7 days a week): BMR × 1.725
  • Extra active (very hard exercise, physical job, or training twice a day): BMR × 1.9

Assuming Suki is moderately active, her caloric needs can be calculated as follows:

\[ \text{Total Calories} = BMR \times 1.55 = 1320.8 \times 1.55 \approx 2047.24 \]

Conclusion

Summary for Suki:

  • BMI: Approximately 26.7 (overweight category)
  • Daily Caloric Intake to maintain weight: Approximately 2047 calories, depending on her activity level.

It's important for Suki to consult a healthcare provider for personalized advice and to consider factors like muscle mass and overall health in addition to weight and BMI.