Estimate your potential weight loss and understand the factors involved.
Excess Weight Loss Calculator
Enter your current weight in kilograms (kg).
Enter your desired target weight in kilograms (kg).
Enter your planned daily calorie deficit multiplied by 7 (e.g., 500 kcal/day * 7 days = 3500 kcal/week).
Average number of days you plan to exercise each week.
Average duration of each exercise session in minutes.
Estimated average calories burned per minute during exercise.
Your Weight Loss Projection
—
Calculates total weight to lose, total weeks required based on calorie deficit, and additional calories burned from exercise.
Total Weight To Lose: — kg
Estimated Weeks To Target: —
Weekly Calories Burned Through Exercise: — kcal
Total Calorie Deficit (Diet + Exercise): — kcal
Weight Loss Progress Over Time
Projected weight loss trajectory based on your inputs.
Detailed Weight Loss Data
Week
Starting Weight (kg)
Weight Lost This Week (kg)
Ending Weight (kg)
A week-by-week breakdown of your weight loss progress.
What is Excess Weight Loss?
{primary_keyword} is a crucial concept for anyone embarking on a weight management journey. It refers to the quantifiable reduction in body mass that surpasses what is considered healthy or necessary for an individual's physiological well-being. Unlike general weight loss, which might simply mean reducing body fat, excess weight loss specifically targets the unhealthy accumulation of weight that can lead to various health complications. Understanding and calculating your excess weight loss helps set realistic goals and monitors progress effectively.
Individuals who are overweight or obese, particularly those diagnosed with conditions like type 2 diabetes, cardiovascular disease, or joint problems, should be concerned with {primary_keyword}. It's about achieving a weight that supports optimal health and reduces risk factors, rather than just reaching a certain number on the scale. A common misconception is that any rapid weight loss is good, but medically unhealthy weight loss can be detrimental, leading to muscle loss, nutrient deficiencies, and metabolic slowdown. This calculator helps delineate healthy, sustainable loss from potentially harmful extremes.
This calculator is designed for individuals seeking to understand their weight loss journey more precisely. It helps quantify the amount of weight that needs to be shed to reach a healthier state and estimates the time it might take, considering both dietary changes and exercise. It's a tool for setting achievable milestones and maintaining motivation by visualizing the path ahead.
{primary_keyword} Formula and Mathematical Explanation
The core of calculating {primary_keyword} involves understanding the relationship between weight, calorie deficits, and the energy expenditure from exercise. A fundamental principle in weight loss is that 1 kilogram of body fat is roughly equivalent to 7700 kilocalories (kcal). Therefore, to lose 1 kg of fat, one needs to create a deficit of 7700 kcal.
Our calculator breaks this down into several key calculations:
1. Total Weight To Lose
This is the difference between your current weight and your target weight. It represents the total amount of mass you aim to reduce to reach your health goals.
Total Weight To Lose = Current Weight - Target Weight
2. Estimated Weeks To Target (Dietary Deficit Only)
This calculation estimates how long it will take to lose the total weight solely based on your planned weekly calorie deficit from diet. It assumes no additional calories burned from exercise, providing a baseline.
This calculates the total calories you can expect to burn through exercise each week, based on your exercise frequency, duration, and intensity (calories burned per minute).
Weekly Exercise Calories = Days Per Week Exercise * Avg Exercise Duration * Avg Calories Burned Per Minute * 60 minutes/hour (if duration is in minutes, which it is)
Wait, the duration is in minutes, so the 60 minutes/hour is not needed here. The formula is simpler:
Weekly Exercise Calories = Days Per Week Exercise * Avg Exercise Duration * Avg Calories Burned Per Minute
4. Total Weekly Calorie Deficit (Diet + Exercise)
This combines your planned dietary deficit with the calories burned through exercise to give you a more realistic total weekly deficit. This value is then used to refine the estimated weeks to target.
Total Weekly Deficit = Weekly Calorie Deficit (from diet) + Weekly Calories Burned Through Exercise
5. Refined Estimated Weeks To Target
This is the most accurate projection, using the combined deficit.
Refined Estimated Weeks = (Total Weight To Lose * 7700 kcal/kg) / Total Weekly Deficit
Important Note: The 7700 kcal/kg is an approximation. Individual metabolic rates, body composition, and other factors can influence the actual rate of weight loss. This calculator provides an estimate.
Variable Explanations
Here's a breakdown of the variables used in our {primary_keyword} calculations:
Variable
Meaning
Unit
Typical Range
Current Weight
Your starting body weight.
kg
30 – 300+
Target Weight
Your desired body weight for health.
kg
30 – 300+
Weekly Calorie Deficit (Diet)
Planned reduction in daily calorie intake, summed over a week.
kcal/week
1000 – 7000 (for 140-1000 kcal/day deficit)
Days Per Week Exercise
Average frequency of exercise sessions.
days/week
0 – 7
Average Exercise Duration
Average length of each exercise session.
minutes
15 – 120
Average Calories Burned Per Minute
Estimated energy expenditure during exercise.
kcal/minute
5 – 20
Total Weight To Lose
The total amount of weight to be lost.
kg
> 0
Estimated Weeks To Target
Projected time to reach target weight.
weeks
1 – 100+
Weekly Exercise Calories
Total calories burned from exercise weekly.
kcal/week
0 – 10000+
Total Weekly Deficit
Combined deficit from diet and exercise.
kcal/week
> 0
Practical Examples (Real-World Use Cases)
Example 1: Moderate Weight Loss Goal
Sarah wants to lose 10 kg. She currently weighs 75 kg and her target weight is 65 kg. She plans to maintain a daily calorie deficit of 500 kcal (3500 kcal/week). She exercises 4 times a week for 45 minutes, burning an average of 8 kcal per minute.
Estimated Weeks To Target: (10 kg * 7700 kcal/kg) / 4940 kcal/week ≈ 15.59 weeks
Interpretation: Sarah can expect to lose approximately 10 kg in about 15.6 weeks if she consistently adheres to her diet and exercise plan. This demonstrates how combining dietary changes with exercise can significantly speed up the weight loss process compared to diet alone.
Example 2: Significant Weight Loss Goal with Higher Exercise Burn
David weighs 120 kg and aims to reach 90 kg, a total of 30 kg to lose. He manages a weekly calorie deficit of 2500 kcal from his diet. He is quite active, exercising 5 days a week for 60 minutes, and estimates burning 12 kcal per minute during his workouts.
Inputs:
Current Weight: 120 kg
Target Weight: 90 kg
Weekly Calorie Deficit: 2500 kcal/week
Days Per Week Exercise: 5
Average Exercise Duration: 60 minutes
Average Calories Burned Per Minute: 12 kcal/minute
Estimated Weeks To Target: (30 kg * 7700 kcal/kg) / 6100 kcal/week ≈ 37.87 weeks
Interpretation: For David, losing 30 kg will require a considerable effort over approximately 38 weeks. Even with a substantial exercise contribution, the large amount of weight to lose means it will be a long-term commitment. This highlights that {primary_keyword} is often a marathon, not a sprint, especially for larger weight loss goals.
How to Use This Calculator Excess Weight Loss
Using our {primary_keyword} calculator is straightforward. Follow these steps to get a personalized projection for your weight loss journey:
Enter Current Weight: Input your current body weight in kilograms (kg) into the "Current Weight" field.
Enter Target Weight: Enter your desired goal weight in kilograms (kg) into the "Target Weight" field. Ensure this target is healthy and realistic for your body type and health status.
Input Weekly Calorie Deficit: Specify the total weekly calorie deficit you aim to achieve through your diet. This is typically calculated by determining your daily calorie needs and subtracting your target daily intake, then multiplying by 7. For example, a 500 kcal/day deficit results in 3500 kcal/week.
Log Exercise Frequency: Enter the average number of days per week you plan to engage in physical activity in the "Days Per Week Exercise" field.
Specify Exercise Duration: Provide the average duration of your exercise sessions in minutes in the "Average Exercise Duration" field.
Estimate Calorie Burn: Estimate the average number of calories you burn per minute during your workouts and enter it into the "Average Calories Burned Per Minute" field. This can vary significantly based on exercise type and intensity.
Calculate: Click the "Calculate" button.
How to Read Results:
Primary Result (Estimated Weeks To Target): This is your main projection, showing the estimated number of weeks it will take to reach your target weight given your inputs.
Total Weight To Lose: The total kilograms you need to shed.
Weekly Calories Burned Through Exercise: The estimated total calories you'll burn from exercise each week.
Total Calorie Deficit: The sum of your dietary deficit and exercise calories burned, indicating your overall weekly energy deficit.
Decision-Making Guidance:
If the projected time seems too long, consider increasing your weekly calorie deficit through a combination of slightly lower intake and more/more intense exercise.
If the projected time is very short, ensure your goals are realistic and sustainable. Rapid weight loss can be unhealthy.
Use the results to set weekly mini-goals and track your progress. Adjust your inputs if your diet or exercise habits change.
Remember that this is an estimate. Factors like metabolic adaptation and adherence play significant roles.
Clicking "Copy Results" will save the key figures to your clipboard, making it easy to share or log your projection. The "Reset" button allows you to clear all fields and start over with new inputs.
Key Factors That Affect {primary_keyword} Results
While the calculator provides a valuable estimate, several real-world factors can influence the actual rate and success of {primary_keyword}. Understanding these can help you set more realistic expectations and adjust your strategy:
Metabolic Rate: Your basal metabolic rate (BMR) – the calories your body burns at rest – is highly individual. Factors like age, sex, muscle mass, and genetics play a significant role. A lower BMR means fewer calories burned naturally, potentially slowing down weight loss. Building muscle mass can help increase your BMR.
Body Composition: The ratio of fat mass to lean muscle mass impacts metabolism. Muscle tissue burns more calories than fat tissue, even at rest. Individuals with higher muscle mass may lose weight faster or require a larger deficit. The calculator uses a general fat-to-kcal conversion which assumes primarily fat loss.
Hormonal Fluctuations: Hormones like leptin, ghrelin, cortisol, and thyroid hormones can significantly affect appetite, metabolism, and fat storage. Stress (cortisol) can promote fat storage, particularly around the abdomen, while hormonal imbalances can make weight loss extremely challenging.
Dietary Adherence and Quality: Consistently sticking to your calorie deficit is paramount. Even small deviations daily can add up. Furthermore, the quality of food matters; nutrient-dense foods promote satiety and overall health, while highly processed foods can be less filling and nutrient-poor, making adherence harder. Understanding your caloric needs is crucial.
Exercise Intensity and Type: The calculator uses an average calorie burn per minute. However, the actual calories burned during exercise vary greatly depending on the intensity (e.g., high-intensity interval training vs. steady-state cardio), type of activity (swimming vs. running), and your body's efficiency. More intense workouts generally burn more calories in less time.
Sleep Quality and Quantity: Insufficient or poor-quality sleep can disrupt hormones that regulate appetite (increasing ghrelin, decreasing leptin), leading to increased hunger and cravings, often for high-calorie foods. It can also affect energy levels for workouts.
Medical Conditions and Medications: Certain health conditions (e.g., hypothyroidism, PCOS) and medications (e.g., some antidepressants, steroids) can affect metabolism and body weight, making {primary_keyword} more difficult. Always consult a healthcare professional if you suspect these factors are impacting your weight.
Age: As people age, metabolic rates tend to slow down, and body composition can shift (muscle loss, fat gain), which can make losing weight progressively harder without adjustments to diet and exercise.
Frequently Asked Questions (FAQ)
Q1: How accurate is the 7700 kcal = 1 kg fat conversion?
A1: The 7700 kcal/kg is a widely accepted approximation for human fat. However, actual weight loss can involve losing water and muscle mass as well, which have different energy densities. So, while it's a good rule of thumb for estimations, real-world results can vary.
Q2: What is considered a healthy rate of weight loss?
A2: Generally, a healthy and sustainable rate of weight loss is considered to be 0.5 to 1 kg (1 to 2 pounds) per week. This usually corresponds to a daily calorie deficit of 500 to 1000 kcal. Faster rates might be possible initially or for individuals with very large amounts of weight to lose, but sustainability and health risks increase.
Q3: My calculator result shows a very long time to reach my goal. What can I do?
A3: To shorten the time, you need to increase your total weekly calorie deficit. This can be achieved by: 1) Reducing your dietary calorie intake further (safely), 2) Increasing the frequency or duration of your exercises, or 3) Engaging in higher-intensity exercises that burn more calories per minute. Always ensure changes are sustainable and healthy.
Q4: Can I lose weight faster by creating a huge calorie deficit?
A4: While a larger deficit leads to faster initial weight loss, it's generally not recommended. Very low-calorie diets can lead to muscle loss, nutrient deficiencies, fatigue, gallstones, and a slowed metabolism, making long-term weight maintenance difficult. It's best to aim for a moderate, sustainable deficit.
Q5: How does exercise contribute to {primary_keyword}?
A5: Exercise contributes in two main ways: 1) It directly burns calories, creating an additional deficit on top of your dietary efforts. 2) It helps build or maintain muscle mass. Muscle tissue is metabolically active and burns more calories at rest than fat, helping to keep your metabolism higher even when you're not exercising.
Q6: What if my weight loss stalls even though I'm following the plan?
A6: Weight loss plateaus are common. They can occur due to metabolic adaptation (your body becomes more efficient), a decrease in adherence to the calorie deficit, or hormonal changes. Re-evaluating your calorie intake and expenditure, increasing exercise intensity, ensuring adequate sleep, and managing stress can help overcome plateaus.
Q7: Does the calculator account for water weight?
A7: No, the calculator primarily estimates fat loss based on calorie deficits. Initial weight loss often includes a significant amount of water weight, which can fluctuate daily. The calculator's "Estimated Weeks" focus on the more consistent fat loss component.
Q8: Should I consult a doctor before using this calculator or starting a weight loss plan?
A8: Yes, it is highly recommended, especially if you have any pre-existing health conditions, are significantly overweight, or are planning drastic changes to your diet or exercise routine. A healthcare professional can provide personalized advice and ensure your weight loss goals are safe and appropriate for you.
// — Calculator Logic —
var KILOGRAM_TO_FAT_CALORIES = 7700;
function getInputValue(id) {
var element = document.getElementById(id);
if (!element) return NaN;
var value = parseFloat(element.value);
return isNaN(value) ? NaN : value;
}
function setErrorMessage(id, message) {
var errorElement = document.getElementById(id + "Error");
if (errorElement) {
if (message) {
errorElement.textContent = message;
errorElement.style.display = 'block';
} else {
errorElement.textContent = ";
errorElement.style.display = 'none';
}
}
}
function isValidNumber(value, min = -Infinity, max = Infinity) {
return typeof value === 'number' && !isNaN(value) && value >= min && value <= max;
}
function calculateExcessWeightLoss() {
var currentWeight = getInputValue("currentWeight");
var targetWeight = getInputValue("targetWeight");
var weeklyCalorieDeficitDiet = getInputValue("weeklyCalorieDeficit");
var daysPerWeekExercise = getInputValue("daysPerWeekExercise");
var avgExerciseDuration = getInputValue("avgExerciseDuration");
var avgCaloriesBurnedPerMinute = getInputValue("avgCaloriesBurnedPerMinute");
var errors = false;
// Validate Current Weight
if (!isValidNumber(currentWeight, 0.1)) {
setErrorMessage("currentWeight", "Please enter a valid current weight (e.g., 75.5).");
errors = true;
} else {
setErrorMessage("currentWeight", "");
}
// Validate Target Weight
if (!isValidNumber(targetWeight, 0.1)) {
setErrorMessage("targetWeight", "Please enter a valid target weight (e.g., 65).");
errors = true;
} else {
setErrorMessage("targetWeight", "");
}
// Validate Weekly Calorie Deficit (Diet)
if (!isValidNumber(weeklyCalorieDeficitDiet, 0)) {
setErrorMessage("weeklyCalorieDeficit", "Please enter a non-negative weekly calorie deficit (e.g., 3500).");
errors = true;
} else {
setErrorMessage("weeklyCalorieDeficit", "");
}
// Validate Days Per Week Exercise
if (!isValidNumber(daysPerWeekExercise, 0, 7)) {
setErrorMessage("daysPerWeekExercise", "Please enter a number between 0 and 7.");
errors = true;
} else {
setErrorMessage("daysPerWeekExercise", "");
}
// Validate Average Exercise Duration
if (!isValidNumber(avgExerciseDuration, 0)) {
setErrorMessage("avgExerciseDuration", "Please enter a valid exercise duration (e.g., 45).");
errors = true;
} else {
setErrorMessage("avgExerciseDuration", "");
}
// Validate Average Calories Burned Per Minute
if (!isValidNumber(avgCaloriesBurnedPerMinute, 0)) {
setErrorMessage("avgCaloriesBurnedPerMinute", "Please enter a valid calorie burn rate (e.g., 8).");
errors = true;
} else {
setErrorMessage("avgCaloriesBurnedPerMinute", "");
}
// Perform calculations only if no errors
if (errors) {
document.getElementById("calculatorResults").style.display = "none";
document.getElementById("weightLossChartContainer").style.display = "none";
document.getElementById("weightLossDataTableContainer").style.display = "none";
return;
}
var totalWeightToLose = currentWeight – targetWeight;
var weeklyExerciseCalories = daysPerWeekExercise * avgExerciseDuration * avgCaloriesBurnedPerMinute;
var totalWeeklyDeficit = weeklyCalorieDeficitDiet + weeklyExerciseCalories;
// Ensure total deficit is positive to avoid infinite loop or negative time
if (totalWeeklyDeficit <= 0) {
setErrorMessage("weeklyCalorieDeficit", "Your total calorie deficit (diet + exercise) must be positive.");
setErrorMessage("avgCaloriesBurnedPerMinute", "Your total calorie deficit (diet + exercise) must be positive.");
errors = true;
document.getElementById("calculatorResults").style.display = "none";
document.getElementById("weightLossChartContainer").style.display = "none";
document.getElementById("weightLossDataTableContainer").style.display = "none";
return;
}
var estimatedWeeks = (totalWeightToLose * KILOGRAM_TO_FAT_CALORIES) / totalWeeklyDeficit;
// Display results
document.getElementById("primaryResult").textContent = estimatedWeeks.toFixed(1) + " weeks";
document.getElementById("totalWeightToLose").textContent = totalWeightToLose.toFixed(1) + " kg";
document.getElementById("estimatedWeeks").textContent = estimatedWeeks.toFixed(1) + " weeks";
document.getElementById("weeklyExerciseCalories").textContent = weeklyExerciseCalories.toFixed(0) + " kcal";
document.getElementById("totalCalorieDeficit").textContent = totalWeeklyDeficit.toFixed(0) + " kcal";
document.getElementById("calculatorResults").style.display = "block";
// Update chart and table
updateWeightLossChart(totalWeightToLose, estimatedWeeks, totalWeeklyDeficit);
updateWeightLossTable(totalWeightToLose, estimatedWeeks, totalWeeklyDeficit);
document.getElementById("weightLossChartContainer").style.display = "block";
document.getElementById("weightLossDataTableContainer").style.display = "block";
}
function resetCalculator() {
document.getElementById("currentWeight").value = "";
document.getElementById("targetWeight").value = "";
document.getElementById("weeklyCalorieDeficit").value = "";
document.getElementById("daysPerWeekExercise").value = "";
document.getElementById("avgExerciseDuration").value = "";
document.getElementById("avgCaloriesBurnedPerMinute").value = "";
document.getElementById("primaryResult").textContent = "–";
document.getElementById("totalWeightToLose").textContent = "– kg";
document.getElementById("estimatedWeeks").textContent = "–";
document.getElementById("weeklyExerciseCalories").textContent = "– kcal";
document.getElementById("totalCalorieDeficit").textContent = "– kcal";
document.getElementById("calculatorResults").style.display = "none";
document.getElementById("weightLossChartContainer").style.display = "none";
document.getElementById("weightLossDataTableContainer").style.display = "none";
// Clear error messages
var errorElements = document.querySelectorAll('.error-message');
for (var i = 0; i < errorElements.length; i++) {
errorElements[i].textContent = '';
errorElements[i].style.display = 'none';
}
}
function copyResults() {
var primaryResultText = document.getElementById("primaryResult").textContent;
var totalWeightToLoseText = document.getElementById("totalWeightToLose").textContent;
var estimatedWeeksText = document.getElementById("estimatedWeeks").textContent;
var weeklyExerciseCaloriesText = document.getElementById("weeklyExerciseCalories").textContent;
var totalCalorieDeficitText = document.getElementById("totalCalorieDeficit").textContent;
var assumptions = "Assumptions:\n";
assumptions += "Weekly Calorie Deficit (Diet): " + (getInputValue("weeklyCalorieDeficit") || 0) + " kcal/week\n";
assumptions += "Days Per Week Exercise: " + (getInputValue("daysPerWeekExercise") || 0) + "\n";
assumptions += "Avg Exercise Duration: " + (getInputValue("avgExerciseDuration") || 0) + " minutes\n";
assumptions += "Avg Calories Burned Per Minute: " + (getInputValue("avgCaloriesBurnedPerMinute") || 0) + " kcal/minute\n";
var textToCopy = "Weight Loss Projection:\n" +
"Estimated Time: " + primaryResultText + "\n" +
"Total Weight To Lose: " + totalWeightToLoseText + "\n" +
"Weekly Exercise Calories Burned: " + weeklyExerciseCaloriesText + "\n" +
"Total Weekly Deficit: " + totalCalorieDeficitText + "\n\n" +
assumptions;
// Use a temporary textarea to copy to clipboard
var textArea = document.createElement("textarea");
textArea.value = textToCopy;
textArea.style.position = "fixed"; // Avoid scrolling to bottom of page in MS Edge.
textArea.style.top = 0;
textArea.style.left = 0;
textArea.style.width = "2em";
textArea.style.height = "2em";
textArea.style.padding = "0";
textArea.style.border = "none";
textArea.style.outline = "none";
textArea.style.boxShadow = "none";
document.body.appendChild(textArea);
textArea.focus();
textArea.select();
try {
var successful = document.execCommand('copy');
var msg = successful ? 'Results copied!' : 'Copying text command was unsuccessful';
console.log(msg);
// Optionally show a temporary success message to the user
var copyButton = document.querySelector('.copy-button');
var originalText = copyButton.textContent;
copyButton.textContent = 'Copied!';
setTimeout(function() {
copyButton.textContent = originalText;
}, 1500);
} catch (err) {
console.error('Fallback: Oops, unable to copy', err);
// Optionally show an error message
var copyButton = document.querySelector('.copy-button');
var originalText = copyButton.textContent;
copyButton.textContent = 'Failed!';
setTimeout(function() {
copyButton.textContent = originalText;
}, 1500);
}
document.body.removeChild(textArea);
}
// — Charting Logic —
var weightLossChartInstance = null;
function updateWeightLossChart(totalWeightToLose, totalWeeks, totalWeeklyDeficit) {
var ctx = document.getElementById('weightLossChart').getContext('2d');
// Clear previous chart instance if it exists
if (weightLossChartInstance) {
weightLossChartInstance.destroy();
}
var labels = [];
var weightData = [];
var targetWeightKg = getInputValue("currentWeight") – totalWeightToLose;
var startingWeightKg = getInputValue("currentWeight");
// Ensure we don't divide by zero or have non-positive deficit
if (totalWeeklyDeficit <= 0) {
console.error("Total weekly deficit is not positive, cannot generate chart data.");
return;
}
// Calculate data points for each week
var weeksToCalculate = Math.min(Math.ceil(totalWeeks), 52); // Limit to 52 weeks for clarity
for (var i = 0; i <= weeksToCalculate; i++) {
labels.push('Week ' + i);
var weightLostThisWeekApprox = (i * totalWeeklyDeficit * KILOGRAM_TO_FAT_CALORIES / 7700) / totalWeeks; // Incorrect. Needs to be linear over total weeks.
var weightLostTotalApprox = (i / weeksToCalculate) * totalWeightToLose; // Linear progression over calculated weeks
var currentWeightOnChart = startingWeightKg – weightLostTotalApprox;
weightData.push(currentWeightOnChart);
if (currentWeightOnChart <= targetWeightKg) {
// If target is reached within the loop, stop adding points or mark it
// For simplicity, we'll var it continue and the target line will show
}
}
// Add a final point if not already the last one, to ensure target is potentially visible
if (labels.length -1 < weeksToCalculate) {
labels.push('Week ' + weeksToCalculate);
weightData.push(startingWeightKg – totalWeightToLose);
}
weightLossChartInstance = new Chart(ctx, {
type: 'line',
data: {
labels: labels,
datasets: [{
label: 'Projected Weight (kg)',
data: weightData,
borderColor: 'var(–primary-color)',
backgroundColor: 'rgba(0, 74, 153, 0.2)',
fill: true,
tension: 0.1
},
{
label: 'Target Weight (kg)',
data: Array(labels.length).fill(targetWeightKg),
borderColor: 'var(–success-color)',
borderDash: [5, 5],
fill: false,
pointRadius: 0 // Don't show points for the target line
}]
},
options: {
responsive: true,
maintainAspectRatio: false, // Allow custom height via canvas element or CSS
scales: {
y: {
beginAtZero: false,
title: {
display: true,
text: 'Weight (kg)'
}
},
x: {
title: {
display: true,
text: 'Time (Weeks)'
}
}
},
plugins: {
tooltip: {
callbacks: {
label: function(context) {
var label = context.dataset.label || '';
if (label) {
label += ': ';
}
if (context.parsed.y !== null) {
label += context.parsed.y.toFixed(1) + ' kg';
}
return label;
}
}
}
}
}
});
}
// — Table Logic —
function updateWeightLossTable(totalWeightToLose, totalWeeks, totalWeeklyDeficit) {
var tableBody = document.querySelector("#weightLossDataTable tbody");
tableBody.innerHTML = ""; // Clear previous rows
var startingWeightKg = getInputValue("currentWeight");
var targetWeightKg = getInputValue("targetWeight");
// Ensure we don't divide by zero or have non-positive deficit
if (totalWeeklyDeficit <= 0) {
console.error("Total weekly deficit is not positive, cannot generate table data.");
return;
}
var weeksToDisplay = Math.min(Math.ceil(totalWeeks), 12); // Limit to 12 weeks for clarity
var weightLostPerWeekApprox = totalWeightToLose / totalWeeks; // Average loss per week over the whole duration
var currentWeight = startingWeightKg;
for (var i = 0; i < weeksToDisplay; i++) {
var weightLostThisWeek = weightLostPerWeekApprox; // Simplified: assume constant loss rate for table
currentWeight -= weightLostThisWeek;
// Ensure we don't go below target weight in the table display for realism
if (currentWeight < targetWeightKg) {
weightLostThisWeek = startingWeightKg – targetWeightKg – (i * weightLostPerWeekApprox);
currentWeight = targetWeightKg;
if (weightLostThisWeek < 0) weightLostThisWeek = 0; // Prevent negative loss if starting calculation wrong
}
// Ensure weightLostThisWeek is positive
if (weightLostThisWeek < 0) weightLostThisWeek = 0;
// Ensure currentWeight doesn't go below target due to floating point math
if (currentWeight targetWeightKg) {
currentWeight = targetWeightKg;
}
var row = tableBody.insertRow();
row.innerHTML = `
${i + 1}
${(startingWeightKg – (i * weightLostPerWeekApprox)).toFixed(1)}
${weightLostThisWeek.toFixed(2)}
${currentWeight.toFixed(1)}
`;
if (currentWeight <= targetWeightKg) {
// Highlight the row where target is met or exceeded
row.style.backgroundColor = "rgba(40, 167, 69, 0.3)"; // Light green tint
}
// Break if we've reached the target weight and don't need more rows
if (currentWeight targetWeightKg) {
// Optionally break or just ensure subsequent rows reflect target weight.
// For now, we'll var subsequent rows show target weight if exceeded.
}
}
}
// Add Chart.js library – only include if not present
(function() {
var scriptId = 'chartjs-script';
if (!document.getElementById(scriptId)) {
var script = document.createElement('script');
script.id = scriptId;
script.src = 'https://cdn.jsdelivr.net/npm/chart.js@3.7.0/dist/chart.min.js'; // Use a specific version
script.onload = function() {
console.log('Chart.js loaded.');
// Initial calculation might be needed if page loads with default values
// calculateExcessWeightLoss(); // Call only if you want calculation on load with defaults
};
script.onerror = function() {
console.error('Failed to load Chart.js.');
};
document.body.appendChild(script);
} else {
console.log('Chart.js already loaded.');
// If chart.js is already loaded, you might want to trigger an initial calculation
// calculateExcessWeightLoss();
}
})();
// Trigger calculation on initial load if inputs have default values (optional)
// document.addEventListener('DOMContentLoaded', function() {
// // You could pre-fill inputs or trigger calculation here if needed
// });