Metabolic Rate Calculator (BMR & TDEE)
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"; resultHtml += "Basal Metabolic Rate (BMR): " + bmr.toFixed(2) + " calories/day"; resultHtml += "Total Daily Energy Expenditure (TDEE): " + tdee.toFixed(2) + " calories/day"; resultHtml += "BMR is the number of calories your body burns at rest to maintain basic functions. TDEE accounts for your physical activity level."; document.getElementById("result").innerHTML = resultHtml; } .calculator-container { font-family: Arial, sans-serif; max-width: 600px; margin: 20px auto; padding: 20px; border: 1px solid #ddd; border-radius: 8px; box-shadow: 0 2px 5px rgba(0,0,0,0.1); } .calculator-container h2 { text-align: center; margin-bottom: 25px; color: #333; } .calculator-inputs { display: grid; grid-template-columns: 1fr 1fr; gap: 15px; margin-bottom: 20px; } .input-group { display: flex; flex-direction: column; } .input-group label { margin-bottom: 8px; font-weight: bold; color: #555; } .input-group input[type="number"], .input-group select { padding: 10px; border: 1px solid #ccc; border-radius: 4px; font-size: 1em; } .calculator-inputs button { grid-column: 1 / -1; padding: 12px 20px; background-color: #007bff; color: white; border: none; border-radius: 4px; font-size: 1.1em; cursor: pointer; transition: background-color 0.3s ease; } .calculator-inputs button:hover { background-color: #0056b3; } .calculator-result { margin-top: 25px; padding: 15px; background-color: #f8f9fa; border: 1px solid #eee; border-radius: 4px; } .calculator-result h3 { margin-top: 0; color: #007bff; } .calculator-result p { margin-bottom: 10px; line-height: 1.6; } .calculator-result small { color: #777; }Understanding Your Metabolic Rate
Your metabolic rate is a crucial factor in understanding how your body uses energy. It's typically discussed in two main components: Basal Metabolic Rate (BMR) and Total Daily Energy Expenditure (TDEE).
Basal Metabolic Rate (BMR)
Your Basal Metabolic Rate (BMR) represents the minimum number of calories your body needs to perform essential life-sustaining activities while at rest. These activities include breathing, circulating blood, maintaining body temperature, cell production, and brain and nerve function. Essentially, it's the energy your body burns just to keep you alive if you were to lie down all day.
Factors influencing BMR include:
- Body Composition: Muscle tissue burns more calories than fat tissue, even at rest.
- Age: BMR typically decreases with age, largely due to a loss of muscle mass.
- Sex: Men generally have a higher BMR than women, primarily because they tend to have more muscle mass and less body fat.
- Genetics: Your inherited traits play a role in your metabolic rate.
- Hormones: Thyroid hormones, in particular, significantly regulate metabolism.
The Mifflin-St Jeor equation, used in this calculator, is a widely accepted formula for estimating BMR:
- For men: BMR = (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) + 5
- For women: BMR = (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) – 161
Total Daily Energy Expenditure (TDEE)
While BMR tells you how many calories you burn at rest, your Total Daily Energy Expenditure (TDEE) accounts for your BMR plus the calories you burn through all your daily activities, including exercise. This is a more comprehensive measure of your daily calorie needs.
TDEE is calculated by multiplying your BMR by an "activity factor" that corresponds to your general lifestyle and exercise habits. The activity factors used in this calculator are standard estimates:
- Sedentary: Little to no exercise. (BMR x 1.2)
- Lightly Active: Light exercise or sports 1-3 days per week. (BMR x 1.375)
- Moderately Active: Moderate exercise or sports 3-5 days per week. (BMR x 1.55)
- Very Active: Hard exercise or sports 6-7 days per week. (BMR x 1.725)
- Extra Active: Very hard exercise or sports and a physical job. (BMR x 1.9)
Why is This Important?
Understanding your BMR and TDEE can be invaluable for several reasons:
- Weight Management: To lose weight, you generally need to consume fewer calories than your TDEE (calorie deficit). To gain weight, you need to consume more calories than your TDEE (calorie surplus). To maintain your current weight, your calorie intake should roughly match your TDEE.
- Fitness Planning: Knowing your energy expenditure helps in designing effective workout routines and ensuring adequate calorie intake to fuel your activities.
- General Health: It provides insight into your body's energy needs and can be a starting point for making informed dietary and lifestyle choices.
Remember that these are estimations. Individual metabolism can vary, and factors like illness, stress, and certain medications can affect your calorie needs. For precise nutritional guidance, it's always best to consult with a healthcare professional or a registered dietitian.