How Much Calories a Day to Lose Weight Calculator

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How Much Calories a Day to Lose Weight Calculator

Estimate your daily calorie needs for weight loss based on your personal details and activity level.

Your Daily Calorie Target for Weight Loss

Enter your weight in kilograms (kg).
Enter your height in centimeters (cm).
Enter your age in years.
Male Female
Sedentary (little or no exercise) Lightly Active (light exercise/sports 1-3 days/week) Moderately Active (moderate exercise/sports 3-5 days/week) Very Active (hard exercise/sports 6-7 days/week) Extra Active (very hard exercise/sports & physical job)
Enter your desired weight in kilograms (kg).
0.25 kg/week (slow and sustainable) 0.5 kg/week (moderate) 0.75 kg/week (faster, requires more commitment) 1 kg/week (aggressive, consult a professional) A healthy rate is typically 0.5-1 kg per week.

Your Weight Loss Calorie Targets

Estimated Daily Calorie Intake:
Your Basal Metabolic Rate (BMR): kcal/day
Total Daily Energy Expenditure (TDEE): kcal/day
Daily Calorie Deficit Needed: kcal/day
Estimated Time to Reach Goal: weeks
Formula Explanation:

We first calculate your Basal Metabolic Rate (BMR) using the Mifflin-St Jeor equation, which estimates calories burned at rest. Then, we multiply BMR by your activity level factor to get your Total Daily Energy Expenditure (TDEE). To lose weight, we create a calorie deficit by subtracting the calories needed to achieve your desired weekly loss rate from your TDEE. (1 kg of fat is approximately 7700 kcal).

Calorie Deficit vs. Weight Loss Rate
Weekly Loss Rate (kg) Approx. Daily Deficit (kcal) Estimated Time to Lose 5kg (weeks)

Understanding How Much Calories a Day to Lose Weight

Embarking on a weight loss journey is a significant step towards improving health and well-being. A cornerstone of successful and sustainable weight loss is understanding your individual calorie needs. This involves determining how many calories you should consume daily to create a deficit that leads to gradual, healthy weight reduction. Our "How Much Calories a Day to Lose Weight Calculator" is designed to provide you with personalized estimates, helping you set realistic goals and make informed dietary choices. Understanding this calorie deficit is paramount to achieving your weight loss aspirations safely and effectively. Many people struggle with weight loss because they don't have a clear understanding of their caloric requirements, leading to either insufficient progress or unsustainable, extreme diets. This guide will delve into the science behind calorie consumption for weight loss, explain the calculator's methodology, and offer practical advice.

What is the How Much Calories a Day to Lose Weight Calculator?

The how much calories a day to lose weight calculator is a specialized tool that estimates your daily caloric intake required to achieve a specific rate of weight loss. It takes into account your current weight, height, age, gender, activity level, and your desired target weight and weekly loss rate. By inputting these personal details, the calculator estimates your Basal Metabolic Rate (BMR) and Total Daily Energy Expenditure (TDEE), then determines the necessary calorie deficit to reach your goal. This isn't about drastic calorie restriction; it's about finding a balanced, sustainable approach. It empowers individuals to create a personalized weight loss plan tailored to their unique physiology and lifestyle. This calculator helps demystify calorie counting for weight loss, making it more accessible and less daunting.

Who Should Use This Calculator?

Anyone looking to lose weight in a controlled and informed manner can benefit from this calculator. Whether you're aiming to shed a few pounds or significantly change your body composition, understanding your calorie needs is the first step. It's particularly useful for individuals:

  • Seeking a structured approach to weight loss.
  • Wanting to avoid unhealthy crash diets.
  • Needing to set realistic weight loss goals.
  • Curious about the caloric implications of different activity levels.
  • Looking for personalized guidance beyond generic diet advice.

This tool is an excellent starting point for anyone serious about managing their weight through dietary adjustments and understanding the energy balance principle. It's a foundational tool for a healthier lifestyle.

Common Misconceptions about Calorie Deficits for Weight Loss

  • "Less is always more": Eating too few calories can slow metabolism and lead to nutrient deficiencies. A moderate deficit is key.
  • "All calories are equal": While calorie balance is crucial, the source of calories (nutrient density) impacts satiety, health, and hormonal balance.
  • "Weight loss is linear": Weight can fluctuate daily due to water retention, hormones, and other factors. Focus on the long-term trend.
  • "Exercise alone is enough": While exercise is vital for health and aids weight loss, diet plays a more significant role in creating a calorie deficit.

Understanding these nuances ensures a more holistic and effective approach to weight management.

How Much Calories a Day to Lose Weight Calculator: Formula and Mathematical Explanation

The core principle behind weight loss is creating a sustained calorie deficit. This means consuming fewer calories than your body burns. Our how much calories a day to lose weight calculator uses a widely accepted methodology involving BMR and TDEE calculations.

Step-by-Step Calculation

  1. Calculate Basal Metabolic Rate (BMR): This is the number of calories your body burns at rest to maintain basic functions like breathing, circulation, and cell production. We use the Mifflin-St Jeor equation, considered one of the most accurate.
    • 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
  2. Calculate Total Daily Energy Expenditure (TDEE): This is your BMR adjusted for your activity level. It represents the total calories you burn in a day.

    TDEE = BMR × Activity Level Factor

    The Activity Level Factors are standardized values:

    • Sedentary: 1.2
    • Lightly Active: 1.375
    • Moderately Active: 1.55
    • Very Active: 1.725
    • Extra Active: 1.9
  3. Determine Daily Calorie Deficit for Weight Loss: To lose weight, you need to consume fewer calories than your TDEE. A common target is a deficit of 500-1000 calories per day for a loss of approximately 0.5-1 kg per week (since 1 kg of fat ≈ 7700 kcal).

    Daily Deficit = (Desired Weekly Loss Rate in kg × 7700 kcal) / 7 days

  4. Calculate Target Daily Calorie Intake: This is your final estimated daily calorie target for weight loss.

    Target Daily Calorie Intake = TDEE – Daily Deficit

  5. Estimate Time to Reach Goal: This calculates how long it might take to reach your target weight.

    Total Weight to Lose = Current Weight – Target Weight

    Time to Goal (weeks) = (Total Weight to Lose × 7700 kcal) / (Desired Weekly Loss Rate × 7700 kcal) = Total Weight to Lose / Desired Weekly Loss Rate

Variable Explanations

Here's a breakdown of the variables used in the calculation:

Variable Meaning Unit Typical Range
Weight Current body mass kg 20 – 500+
Height Body height cm 50 – 250+
Age Age of the individual Years 1 – 120+
Gender Biological sex (influences BMR calculation) Male/Female N/A
Activity Level Factor Multiplier for daily calorie expenditure based on lifestyle Unitless 1.2 – 1.9
Target Weight Desired body mass for weight loss kg 10 – 500+ (should be less than current weight)
Desired Weekly Loss Rate Rate at which you aim to lose weight kg/week 0.25 – 1.0 (recommended range)
BMR Basal Metabolic Rate (calories burned at rest) kcal/day Varies widely based on inputs
TDEE Total Daily Energy Expenditure (total calories burned daily) kcal/day Varies widely based on inputs
Daily Deficit Calorie difference needed to achieve desired weight loss kcal/day Varies based on loss rate
Target Daily Calorie Intake Recommended daily calorie consumption for weight loss kcal/day Varies based on TDEE and deficit
Time to Goal Estimated duration to reach target weight Weeks Varies widely

Practical Examples (Real-World Use Cases)

Let's illustrate how the how much calories a day to lose weight calculator works with two distinct scenarios:

Example 1: Sarah, aiming for moderate weight loss

  • Current Weight: 70 kg
  • Height: 165 cm
  • Age: 28 years
  • Gender: Female
  • Activity Level: Lightly Active (exercises 1-3 times/week)
  • Target Weight: 65 kg
  • Desired Weekly Loss Rate: 0.5 kg/week

Calculation Steps:

  1. BMR (Sarah): (10 × 70) + (6.25 × 165) – (5 × 28) – 161 = 700 + 1031.25 – 140 – 161 = 1430.25 kcal/day
  2. TDEE (Sarah): 1430.25 × 1.375 (Lightly Active) = 1966.09 kcal/day
  3. Daily Deficit: (0.5 kg × 7700 kcal) / 7 days = 550 kcal/day
  4. Target Daily Calorie Intake: 1966.09 – 550 = 1416.09 kcal/day
  5. Time to Goal: (70 kg – 65 kg) / 0.5 kg/week = 5 kg / 0.5 kg/week = 10 weeks

Interpretation: Sarah should aim to consume approximately 1416 calories per day to lose about 0.5 kg per week. This moderate approach is sustainable and helps her reach her goal weight in about 10 weeks. The calculator would provide these results, highlighting the primary target and intermediate values.

Example 2: Mark, aiming for faster weight loss

  • Current Weight: 95 kg
  • Height: 180 cm
  • Age: 35 years
  • Gender: Male
  • Activity Level: Moderately Active (exercises 3-5 times/week)
  • Target Weight: 85 kg
  • Desired Weekly Loss Rate: 1 kg/week

Calculation Steps:

  1. BMR (Mark): (10 × 95) + (6.25 × 180) – (5 × 35) + 5 = 950 + 1125 – 175 + 5 = 1905 kcal/day
  2. TDEE (Mark): 1905 × 1.55 (Moderately Active) = 2952.75 kcal/day
  3. Daily Deficit: (1 kg × 7700 kcal) / 7 days = 1100 kcal/day
  4. Target Daily Calorie Intake: 2952.75 – 1100 = 1852.75 kcal/day
  5. Time to Goal: (95 kg – 85 kg) / 1 kg/week = 10 kg / 1 kg/week = 10 weeks

Interpretation: Mark needs a significant daily deficit of about 1100 calories, bringing his target intake to roughly 1853 calories per day. This more aggressive rate aims to help him lose 10 kg in approximately 10 weeks. It's crucial for Mark to ensure his diet is nutrient-dense at this calorie level and potentially consult a healthcare professional for such an aggressive goal. The calculator provides these precise figures for informed decision-making.

How to Use This How Much Calories a Day to Lose Weight Calculator

Using the how much calories a day to lose weight calculator is straightforward. Follow these simple steps:

  1. Enter Your Details: Accurately input your current weight (kg), height (cm), age (years), and select your gender.
  2. Specify Your Activity Level: Choose the option that best describes your typical weekly physical activity. Be honest to get the most accurate TDEE estimate.
  3. Set Your Weight Loss Goal: Enter your target weight (kg) and select your desired weekly weight loss rate (kg/week). A rate of 0.5 kg/week is generally recommended for sustainability.
  4. Click "Calculate": The calculator will instantly process your inputs.

How to Read the Results

  • Estimated Daily Calorie Intake: This is your primary target – the number of calories you should aim to consume each day to achieve your desired weight loss rate.
  • Your BMR: Your baseline calorie burn at rest.
  • TDEE: Your total estimated daily calorie burn, including activity.
  • Daily Calorie Deficit Needed: The difference between your TDEE and your target intake, crucial for fat loss.
  • Estimated Time to Reach Goal: A projection of how long it might take to hit your target weight based on your chosen loss rate.

Decision-Making Guidance

The results provide a roadmap, but remember these points:

  • Sustainability is Key: Choose a calorie intake and loss rate you can maintain long-term. Extreme deficits are hard to stick to and can be detrimental to health.
  • Nutrient Density Matters: Focus on whole, unprocessed foods to ensure you're getting essential vitamins and minerals even with a reduced calorie intake. Explore healthy eating habits.
  • Listen to Your Body: Pay attention to hunger cues, energy levels, and overall well-being. Adjustments may be necessary.
  • Consult Professionals: For significant weight loss goals or if you have underlying health conditions, consult a doctor or a registered dietitian.
  • Combine with Exercise: While diet is primary for a calorie deficit, regular physical activity improves body composition, boosts metabolism, and enhances overall health. Consider our exercise calorie calculator.

This calculator is a tool, not a rigid prescription. Use it as a guide to inform your choices and create a personalized weight loss plan.

Key Factors That Affect Calorie Needs for Weight Loss

Several factors influence your daily calorie requirements for weight loss, extending beyond the basic inputs of our calculator. Understanding these can help you refine your approach:

  1. Metabolism: Individual metabolic rates can vary due to genetics, muscle mass, age, and hormonal factors. Someone with a naturally faster metabolism will burn more calories at rest.
  2. Muscle Mass: Muscle tissue is metabolically active, meaning it burns more calories than fat tissue, even at rest. Building or maintaining muscle mass can increase your BMR and TDEE. Strength training for weight loss can be beneficial.
  3. Hormonal Balance: Hormones like thyroid hormones, cortisol, and insulin play significant roles in regulating metabolism and appetite. Imbalances can affect weight loss efforts.
  4. Diet Composition: While the calculator focuses on total calories, the macronutrient balance (protein, carbs, fats) affects satiety and thermic effect of food (calories burned during digestion). Higher protein intake, for example, can increase satiety and boost metabolism slightly.
  5. Sleep Quality and Quantity: Poor sleep can disrupt hormones like ghrelin and leptin (appetite regulators) and increase cortisol, potentially leading to increased hunger and fat storage.
  6. Thermic Effect of Food (TEF): Different macronutrients require different amounts of energy to digest. Protein has the highest TEF, followed by carbohydrates, and then fats. This is a minor factor but contributes to overall expenditure.
  7. Environmental Factors: Extreme temperatures can slightly affect calorie expenditure as the body works to maintain its core temperature.
  8. Medications and Health Conditions: Certain medications or health conditions (like PCOS or hypothyroidism) can impact metabolism and make weight loss more challenging, often requiring tailored approaches.

These factors highlight why personalized plans, possibly guided by a professional, are often more effective than generic calorie targets. Always consider consulting with a healthcare provider or a registered dietitian for personalized advice, especially when dealing with specific health conditions or significant weight loss goals. They can help you navigate complex factors like managing blood sugar for weight loss or understanding the impact of specific dietary patterns.

Frequently Asked Questions (FAQ)

What is the safest rate of weight loss?

The safest and most sustainable rate of weight loss is generally considered to be 0.5 to 1 kg (1 to 2 pounds) per week. Losing weight faster than this can lead to muscle loss, nutrient deficiencies, and is often harder to maintain long-term.

Can I eat less than 1200 calories a day?

For most adults, especially men, consuming fewer than 1200 calories per day is generally not recommended without medical supervision. Such a low intake can be difficult to sustain, may lead to nutrient deficiencies, slow metabolism, and cause excessive fatigue. The calculator aims for a more balanced deficit.

Does the calculator account for exercise calories burned?

Yes, indirectly. The 'Activity Level' factor in the calculator is an estimation of your average daily calorie burn, which includes baseline activity and regular exercise. If you engage in intense or prolonged workouts, you might burn more calories than estimated, potentially allowing for a slightly higher intake or faster loss. However, it's best to use the calculated TDEE as a baseline and adjust based on your actual results and energy levels.

What if my target weight is very close to my current weight?

If your target weight is only a few kilograms away from your current weight, the calculator will still provide an estimate. However, achieving smaller amounts of weight loss can sometimes be slower as your body becomes more efficient. Consider focusing on body composition changes (increasing muscle, decreasing fat) rather than just scale weight in such cases.

How accurate is the Mifflin-St Jeor equation?

The Mifflin-St Jeor equation is considered one of the most accurate predictive equations for BMR currently available. However, it's still an estimate. Individual metabolic variations mean that actual calorie needs can differ. The calculator provides a strong starting point, but monitoring your progress and adjusting is essential.

Why is my calorie deficit so large for a 1kg/week loss?

Losing 1 kg of body fat requires a deficit of approximately 7700 kcal. To achieve this in a week, you need a daily deficit of about 1100 kcal (7700 / 7). If your TDEE is, for example, 2500 kcal, a 1100 kcal deficit means a target intake of 1400 kcal. This is why aggressive loss rates require significant adjustments and careful nutritional planning.

Should I track my food intake precisely?

Tracking your food intake using apps or journals can be very helpful, especially when starting, to ensure you're meeting your calorie targets and getting adequate nutrition. It helps build awareness of portion sizes and calorie density of foods. However, the goal is sustainable habits, not necessarily lifelong obsessive tracking for everyone.

What happens if I go over my calorie target sometimes?

Occasional deviations from your calorie target are normal and don't typically derail progress significantly. The key is consistency over time. If you exceed your target one day, simply return to your plan the next day. Focus on the overall weekly average deficit rather than stressing over single days.

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Daily Deficit (kcal)', data: chartData.deficitData, backgroundColor: 'rgba(0, 74, 153, 0.6)', // Primary color borderColor: 'rgba(0, 74, 153, 1)', borderWidth: 1, yAxisID: 'y-axis-deficit' // Assign to left Y-axis }, { label: 'Time to Goal (Weeks)', data: chartData.timeData, type: 'line', // Use line for time axis borderColor: 'rgba(40, 167, 69, 0.8)', // Success color backgroundColor: 'rgba(40, 167, 69, 0.2)', borderWidth: 2, fill: false, yAxisID: 'y-axis-time' // Assign to right Y-axis }] }, options: { responsive: true, maintainAspectRatio: false, scales: { x: { title: { display: true, text: 'Timeframe' } }, 'y-axis-deficit': { type: 'linear', position: 'left', title: { display: true, text: 'Daily Calorie Deficit (kcal)' }, ticks: { beginAtZero: true } }, 'y-axis-time': { type: 'linear', position: 'right', title: { display: true, text: 'Weeks to Reach Goal' }, ticks: { beginAtZero: true }, grid: { drawOnChartArea: false, // only want the grid lines for one axis to show up } } }, plugins: { title: { display: true, text: 'Weight Loss Progression Simulation', font: { size: 16 } }, legend: { display: true } } } }); } // Function to populate table function populateTable() { var tableBody = document.querySelector("#calorieChart").nextElementSibling.querySelector("tbody"); tableBody.innerHTML = ''; // Clear existing rows var rates = [0.25, 0.5, 0.75, 1.0]; var initialWeight = parseFloat(document.getElementById('weight').value); var targetWeight = parseFloat(document.getElementById('goalWeight').value); var currentTdee = parseFloat(document.getElementById('tdeeResult').innerText.replace(' kcal/day', '')); // Get TDEE from results section if (isNaN(initialWeight) || isNaN(targetWeight) || initialWeight <= targetWeight) { // If initial inputs are invalid or no weight to lose, don't populate table meaningfully // Or show a message return; } rates.forEach(function(rate) { var dailyDeficit = (rate * 7700) / 7; var timeToGoal = (initialWeight – targetWeight) / rate; var row = tableBody.insertRow(); var cell1 = row.insertCell(0); var cell2 = row.insertCell(1); var cell3 = row.insertCell(2); cell1.textContent = rate.toFixed(2); cell2.textContent = dailyDeficit.toFixed(0); cell3.textContent = timeToGoal.toFixed(1); }); } // Function to validate input and calculate function calculateCalories() { // Reset errors document.getElementById('weightError').textContent = ''; document.getElementById('heightError').textContent = ''; document.getElementById('ageError').textContent = ''; document.getElementById('genderError').textContent = ''; document.getElementById('activityLevelError').textContent = ''; document.getElementById('goalWeightError').textContent = ''; document.getElementById('lossRateError').textContent = ''; 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 activityLevel = parseFloat(document.getElementById('activityLevel').value); var goalWeight = parseFloat(document.getElementById('goalWeight').value); var lossRate = parseFloat(document.getElementById('lossRate').value); var isValid = true; if (isNaN(weight) || weight <= 0) { document.getElementById('weightError').textContent = 'Please enter a valid weight.'; isValid = false; } if (isNaN(height) || height <= 0) { document.getElementById('heightError').textContent = 'Please enter a valid height.'; isValid = false; } if (isNaN(age) || age <= 0) { document.getElementById('ageError').textContent = 'Please enter a valid age.'; isValid = false; } if (isNaN(goalWeight) || goalWeight <= 0) { document.getElementById('goalWeightError').textContent = 'Please enter a valid target weight.'; isValid = false; } if (weight <= goalWeight) { document.getElementById('goalWeightError').textContent = 'Target weight must be less than current weight.'; isValid = false; } if (isNaN(activityLevel)) { document.getElementById('activityLevelError').textContent = 'Please select an activity level.'; isValid = false; } if (isNaN(lossRate)) { document.getElementById('lossRateError').textContent = 'Please select a loss rate.'; isValid = false; } if (!isValid) { document.getElementById('results').style.display = 'none'; return; } // Calculate BMR (Mifflin-St Jeor Equation) var bmr; if (gender === 'male') { bmr = (10 * weight) + (6.25 * height) – (5 * age) + 5; } else { // female bmr = (10 * weight) + (6.25 * height) – (5 * age) – 161; } // Calculate TDEE var tdee = bmr * activityLevel; // Calculate Daily Deficit based on desired weekly loss rate // 1 kg of fat is approx 7700 kcal var dailyDeficit = (lossRate * 7700) / 7; // Calculate Target Daily Calorie Intake var targetDailyCalories = tdee – dailyDeficit; // Calculate Time to Goal var weightToLose = weight – goalWeight; var timeToGoalWeeks = weightToLose / lossRate; // Ensure target calories are not excessively low (e.g., below 1200 for women, 1500 for men) var minCaloriesForWoman = 1200; var minCaloriesForMan = 1500; var minCalories = (gender === 'female') ? minCaloriesForWoman : minCaloriesForMan; if (targetDailyCalories 0) { var adjustedLossRate = dailyDeficit * 7 / 7700; timeToGoalWeeks = weightToLose / adjustedLossRate; } else { timeToGoalWeeks = Infinity; // Cannot lose weight if deficit is not positive } } // Display Results document.getElementById('bmrResult').textContent = bmr.toFixed(0); document.getElementById('tdeeResult').textContent = tdee.toFixed(0); document.getElementById('deficitResult').textContent = dailyDeficit.toFixed(0); document.getElementById('targetDailyCalories').textContent = targetDailyCalories.toFixed(0) + " kcal/day"; document.getElementById('timeToGoal').textContent = timeToGoalWeeks.toFixed(1); document.getElementById('results').style.display = 'block'; // Update the chart and table updateChart(weight, goalWeight, lossRate); populateTable(); } // Function to reset calculator function resetCalculator() { document.getElementById('weight').value = '70'; document.getElementById('height').value = '175'; document.getElementById('age').value = '30'; document.getElementById('gender').value = 'male'; document.getElementById('activityLevel').value = '1.55'; // Moderately Active document.getElementById('goalWeight').value = '65'; document.getElementById('lossRate').value = '0.5'; // 0.5 kg/week // Clear errors and hide results document.getElementById('weightError').textContent = "; document.getElementById('heightError').textContent = "; document.getElementById('ageError').textContent = "; document.getElementById('genderError').textContent = "; document.getElementById('activityLevelError').textContent = "; document.getElementById('goalWeightError').textContent = "; document.getElementById('lossRateError').textContent = "; document.getElementById('results').style.display = 'none'; // Reset chart and table chartData.labels = []; chartData.deficitData = []; chartData.timeData = []; if (calorieChartInstance) { calorieChartInstance.destroy(); calorieChartInstance = null; } var tableBody = document.querySelector("#calorieChart").nextElementSibling.querySelector("tbody"); tableBody.innerHTML = "; } // Function to copy results function copyResults() { var bmr = document.getElementById('bmrResult').textContent; var tdee = document.getElementById('tdeeResult').textContent; var deficit = document.getElementById('deficitResult').textContent; var targetCalories = document.getElementById('targetDailyCalories').textContent; var timeToGoal = document.getElementById('timeToGoal').textContent; var weight = document.getElementById('weight').value; var height = document.getElementById('height').value; var age = document.getElementById('age').value; var gender = document.getElementById('gender').value; var activityLevelText = document.getElementById('activityLevel').options[document.getElementById('activityLevel').selectedIndex].text; var goalWeight = document.getElementById('goalWeight').value; var lossRateText = document.getElementById('lossRate').options[document.getElementById('lossRate').selectedIndex].text; var resultsText = "— Your Weight Loss Calorie Targets —\n\n"; resultsText += "Inputs:\n"; resultsText += " Current Weight: " + weight + " kg\n"; resultsText += " Height: " + height + " cm\n"; resultsText += " Age: " + age + " years\n"; resultsText += " Gender: " + gender + "\n"; resultsText += " Activity Level: " + activityLevelText + "\n"; resultsText += " Target Weight: " + goalWeight + " kg\n"; resultsText += " Desired Loss Rate: " + lossRateText + "\n\n"; resultsText += "Calculated Results:\n"; resultsText += " Estimated Daily Calorie Intake: " + targetCalories + "\n"; resultsText += " Your Basal Metabolic Rate (BMR): " + bmr + "\n"; resultsText += " Total Daily Energy Expenditure (TDEE): " + tdee + "\n"; resultsText += " Daily Calorie Deficit Needed: " + deficit + "\n"; resultsText += " Estimated Time to Reach Goal: " + timeToGoal + " weeks\n\n"; resultsText += "Formula Used: Mifflin-St Jeor for BMR, adjusted for TDEE, and then a deficit is created for weight loss based on a 7700 kcal/kg fat approximation."; // Use navigator.clipboard for modern browsers if (navigator.clipboard && window.isSecureContext) { navigator.clipboard.writeText(resultsText).then(function() { alert('Results copied to clipboard!'); }).catch(function(err) { console.error('Failed to copy: ', err); // Fallback for environments where clipboard API isn't available or fails var textArea = document.createElement("textarea"); textArea.value = resultsText; textArea.style.position = "fixed"; // Avoid scrolling to bottom document.body.appendChild(textArea); textArea.focus(); textArea.select(); try { document.execCommand('copy'); alert('Results copied to clipboard!'); } catch (e) { alert('Failed to copy results. Please copy manually.'); console.error('Copy command failed: ', e); } document.body.removeChild(textArea); }); } else { // Fallback for older browsers or non-HTTPS contexts var textArea = document.createElement("textarea"); textArea.value = resultsText; textArea.style.position = "fixed"; // Avoid scrolling to bottom document.body.appendChild(textArea); textArea.focus(); textArea.select(); try { document.execCommand('copy'); alert('Results copied to clipboard!'); } catch (e) { alert('Failed to copy results. Please copy manually.'); console.error('Copy command failed: ', e); } document.body.removeChild(textArea); } } // Initial chart library load – assuming Chart.js is available globally. // In a real WordPress environment, you'd enqueue this script properly. // For this self-contained HTML, we'll assume it's loaded externally or provide a placeholder. // To make this runnable in a single file for demonstration, you might include Chart.js CDN link in head: // // For this example, we proceed assuming Chart.js is available. // If running this as a pure HTML file, add the CDN link in the section. // Initialize chart and table on load if default values exist document.addEventListener('DOMContentLoaded', function() { // Check if default values are set and calculate if so var weightInput = document.getElementById('weight'); if (weightInput && weightInput.value) { calculateCalories(); } });

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