1. What is the NHS Calorie Requirement Calculator?

The NHS Calorie Requirement Calculator estimates your daily calorie needs based on the Harris-Benedict equation, which calculates your Basal Metabolic Rate (BMR) and adjusts for physical activity level.

2. How Does the Calculator Work?

The calculator uses the Harris-Benedict equation:

Where:

• \( BMR \) — Basal Metabolic Rate (calculated differently for men and women)
• \( activity\_factor \) — Multiplier based on physical activity level
• \( deficit \) — Optional calorie reduction for weight loss

BMR Formulas:
For men: \( BMR = 88.362 + (13.397 \times weight) + (4.799 \times height) - (5.677 \times age) \)
For women: \( BMR = 447.593 + (9.247 \times weight) + (3.098 \times height) - (4.330 \times age) \)

3. Importance of Calorie Calculation

Details: Knowing your daily calorie requirements helps with weight management, whether your goal is maintenance, loss, or gain. The NHS recommends gradual weight loss of 0.5-1kg per week.

4. Using the Calculator

Tips: Enter your gender, age, weight in kg, height in cm, and select your activity level. For weight loss, you can optionally specify a calorie deficit (typically 500 kcal/day for 0.5kg/week loss).

5. Frequently Asked Questions (FAQ)

Q1: How accurate is this calculator?
A: It provides a good estimate for most people, but individual metabolism can vary by ±15%. For precise needs, consult a dietitian.

Q2: What's a safe calorie deficit for weight loss?
A: NHS recommends no more than 500-600 kcal deficit per day for sustainable weight loss.

Q3: Should I eat back exercise calories?
A: The activity factor already accounts for regular exercise. Only eat additional calories if doing unusual extra activity.

Q4: How often should I recalculate my needs?
A: Recalculate every 5-10kg of weight change or if your activity level changes significantly.

Q5: Are there limitations to this calculator?
A: It may be less accurate for athletes, pregnant women, or those with certain medical conditions affecting metabolism.