Metabolic Rate Calculator Nhs

NHS-Style Metabolic Rate Calculator

Male Female

Sedentary (Little/no exercise) Lightly Active (1-3 days/week) Moderately Active (3-5 days/week) Very Active (6-7 days/week) Extra Active (Physical job/training)

function calculateMetabolicRate() { var weight = parseFloat(document.getElementById('weight').value); var height = parseFloat(document.getElementById('height').value); var age = parseFloat(document.getElementById('age').value); var gender = document.getElementById('gender').value; var activity = parseFloat(document.getElementById('activity').value); if (!weight || !height || !age) { alert('Please fill in all fields with valid numbers.'); return; } var bmr = 0; // Mifflin-St Jeor Equation if (gender === 'male') { bmr = (10 * weight) + (6.25 * height) – (5 * age) + 5; } else { bmr = (10 * weight) + (6.25 * height) – (5 * age) – 161; } var tdee = bmr * activity; document.getElementById('bmr-output').innerText = Math.round(bmr).toLocaleString(); document.getElementById('tdee-output').innerText = Math.round(tdee).toLocaleString(); var loss = Math.round(tdee – 500); document.getElementById('recommendation').innerText = "To lose weight safely (approx. 0.5kg/1lb per week), aim for around " + loss.toLocaleString() + " calories per day."; document.getElementById('results').style.display = 'block'; }

Understanding Your Metabolic Rate

Knowing your metabolic rate is a fundamental step in weight management and general health. Based on principles used by clinical health services like the NHS, this calculator estimates how many calories your body burns at rest and during your daily activities.

BMR vs. TDEE: What's the Difference?

• Basal Metabolic Rate (BMR): This is the number of calories your body needs to maintain basic life functions, such as breathing, blood circulation, and cell production, while at complete rest.
• Total Daily Energy Expenditure (TDEE): This is the total number of calories you burn in a 24-hour period, including physical movement and the thermic effect of food.

How the Calculation Works

This tool utilizes the Mifflin-St Jeor Equation, which is currently considered the most accurate formula for predicting energy expenditure in healthy adults. It takes into account your biological sex, weight, height, and age to determine your metabolic baseline.

Realistic Example

Consider a 35-year-old male who weighs 85kg and is 180cm tall. If he has a "Moderately Active" lifestyle (exercising 3-5 times a week):

• BMR: Approximately 1,830 kcal
• Maintenance (TDEE): Approximately 2,836 kcal
• Weight Loss Goal: To lose 0.5kg per week, he would target roughly 2,336 kcal daily.

NHS Guidelines for Healthy Weight Loss

The NHS generally recommends that for sustainable weight loss, men should aim for a daily calorie intake of about 1,900kcal and women about 1,400kcal, depending on their starting point. It is vital not to drop below your BMR without medical supervision, as your body needs those calories for organ function. Always consult with a healthcare professional before making significant changes to your diet or exercise regime.