Macro Calculator for Weight Loss
body {
font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
background-color: #f8f9fa;
color: #333;
line-height: 1.6;
margin: 0;
padding: 20px;
display: flex;
justify-content: center;
align-items: flex-start; /* Align to top */
min-height: 100vh;
}
.loan-calc-container {
background-color: #ffffff;
padding: 30px;
border-radius: 8px;
box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
max-width: 800px;
width: 100%;
margin-bottom: 40px; /* Space between calculator and article */
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h1, h2 {
color: #004a99;
text-align: center;
margin-bottom: 20px;
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.input-group {
margin-bottom: 20px;
display: flex;
align-items: center;
gap: 15px;
flex-wrap: wrap; /* Allow wrapping on smaller screens */
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flex: 1; /* Allow label to take space */
min-width: 150px; /* Minimum width for labels */
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color: #004a99;
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.input-group input[type="number"],
.input-group select {
flex: 1.5; /* Input takes more space */
padding: 12px 15px;
border: 1px solid #ced4da;
border-radius: 4px;
font-size: 1rem;
box-sizing: border-box; /* Include padding and border in element's total width and height */
min-width: 180px; /* Ensure inputs don't get too small */
}
/* Special styling for the select element to match input feel */
.input-group select {
background-color: white; /* Default background */
appearance: none; /* Remove default dropdown arrow */
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transition: background-color 0.3s ease;
display: block; /* Make button take full width */
width: 100%;
margin-top: 10px; /* Space above button */
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button:hover {
background-color: #003366;
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#result {
margin-top: 30px;
padding: 25px;
background-color: #e9ecef;
border-left: 5px solid #28a745;
border-radius: 4px;
text-align: center;
font-size: 1.3rem;
font-weight: bold;
color: #004a99;
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#result.show {
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#result span {
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color: #555;
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.article-content li {
margin-left: 20px;
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@media (max-width: 768px) {
.input-group {
flex-direction: column; /* Stack inputs on smaller screens */
align-items: stretch; /* Stretch to full width */
}
.input-group label,
.input-group input[type="number"],
.input-group select {
flex: none; /* Remove flex properties */
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}
Macro Calculator for Weight Loss
Male
Female
Sedentary (little to no exercise)
Lightly Active (exercise 1-3 days/week)
Moderately Active (exercise 3-5 days/week)
Very Active (exercise 6-7 days/week)
Extra Active (very intense exercise & physical job)
Your daily macro targets for weight loss are:
g Protein
g Fat
g Carbohydrates
Total Daily Calories: kcal
Understanding Macronutrients and Weight Loss
Calculating your macronutrient (macros) targets is a cornerstone of effective and sustainable weight loss. Macros are the three primary nutrients your body needs: protein, fat, and carbohydrates. By strategically adjusting your intake of these, you can create a calorie deficit necessary for weight loss while ensuring your body receives the fuel and building blocks it needs.
1. Calculate Your Basal Metabolic Rate (BMR)
Your BMR is the number of calories your body burns at rest to maintain basic functions. We can estimate this using the Mifflin-St Jeor equation, which is widely 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. Determine Your Total Daily Energy Expenditure (TDEE)
Your TDEE is the total number of calories you burn in a day, accounting for your BMR and your activity level. It's calculated by multiplying your BMR by an activity factor:
Your TDEE represents the calories you need to maintain your current weight.
3. Create a Calorie Deficit for Weight Loss
To lose weight, you need to consume fewer calories than your TDEE. A safe and sustainable rate of weight loss is typically 0.5 kg to 1 kg per week.
Approximately 3500 calories equal 0.5 kg of fat.
To lose 0.5 kg per week, you need a deficit of about 500 calories per day (3500 calories / 7 days).
To lose 1 kg per week, you need a deficit of about 1000 calories per day.
For this calculator, we've set common deficit targets (0.25kg to 1.0kg per week), which translate to daily calorie deficits of approximately 250 to 1000 calories.
Target Calories = TDEE – Daily Calorie Deficit
4. Distribute Macronutrients
Once you have your target daily calories, you can distribute them among protein, fat, and carbohydrates. Here's a common approach for weight loss:
Protein: Aim for 1.6 to 2.2 grams of protein per kilogram of body weight. Protein is crucial for muscle preservation during weight loss and helps with satiety. (4 calories per gram)
Fat: Aim for 0.5 to 1 gram of fat per kilogram of body weight. Healthy fats are essential for hormone function and nutrient absorption. (9 calories per gram)
Carbohydrates: Fill the remaining calories with carbohydrates. Carbohydrates provide energy for your body and brain. (4 calories per gram)
The calculation is as follows:
Calculate target protein calories: (Protein g/kg * Weight kg) * 4
Calculate remaining calories for carbohydrates: Target Calories – Protein Calories – Fat Calories
Convert carb calories to grams: Carb Calories / 4
This calculator uses the middle-to-higher end of protein recommendations (1.8g/kg), the middle of fat recommendations (0.8g/kg), and then calculates carbs to meet your target calorie goal.
Example Calculation:
Let's say you are a 30-year-old male, weighing 75 kg, 170 cm tall, moderately active, and aiming to lose 0.5 kg per week.
Carbohydrate Grams: 1005 kcal / 4 kcal/g = 251.25 g (rounded to 251 g)
So, your daily macros would be approximately 135g Protein, 60g Fat, and 251g Carbohydrates, totaling around 2085 calories.
function calculateMacros() {
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 weightLossPerWeek = parseFloat(document.getElementById("goal").value);
var resultDiv = document.getElementById("result");
var proteinGramsSpan = document.getElementById("proteinGrams");
var fatGramsSpan = document.getElementById("fatGrams");
var carbsGramsSpan = document.getElementById("carbsGrams");
var totalCaloriesSpan = document.getElementById("totalCalories");
// Clear previous results and hide the div
resultDiv.classList.remove('show');
proteinGramsSpan.textContent = "";
fatGramsSpan.textContent = "";
carbsGramsSpan.textContent = "";
totalCaloriesSpan.textContent = "";
// Input validation
if (isNaN(weight) || weight <= 0 ||
isNaN(height) || height <= 0 ||
isNaN(age) || age <= 0 ||
isNaN(activityLevel) ||
isNaN(weightLossPerWeek) || weightLossPerWeek <= 0) {
alert("Please enter valid positive numbers for weight, height, age, and a valid weight loss goal.");
return;
}
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;
}
var tdee = bmr * activityLevel;
var calorieDeficitPerDay = weightLossPerWeek * 1100; // Approx 1100 kcal per 0.5kg (3500 kcal / 7 days)
var targetCalories = tdee – calorieDeficitPerDay;
// Ensure target calories are not too low, a minimum of 1200 for women, 1500 for men is often recommended
if (gender === "female" && targetCalories < 1200) {
targetCalories = 1200;
alert("Your calculated target calories are very low. Setting to a minimum of 1200 kcal for health reasons.");
} else if (gender === "male" && targetCalories < 1500) {
targetCalories = 1500;
alert("Your calculated target calories are very low. Setting to a minimum of 1500 kcal for health reasons.");
}
// Macro calculation parameters
var proteinGramsPerKg = 1.8; // grams per kg of body weight
var fatGramsPerKg = 0.8; // grams per kg of body weight
var proteinGrams = weight * proteinGramsPerKg;
var proteinCalories = proteinGrams * 4;
var fatGrams = weight * fatGramsPerKg;
var fatCalories = fatGrams * 9;
var carbCalories = targetCalories – proteinCalories – fatCalories;
var carbGrams = carbCalories / 4;
// Ensure carb calories are not negative
if (carbGrams < 0) {
// Adjust fat or protein if carbs are negative, or notify user
// For simplicity, we'll cap carbs at 0 and adjust fat slightly if needed, or alert.
alert("Calculation resulted in negative carbohydrate calories. Please adjust your inputs or goals.");
carbGrams = 0; // Cap at zero
// Potentially adjust fat slightly if needed for caloric balance, but for now alert is sufficient.
}
// Display results
proteinGramsSpan.textContent = Math.round(proteinGrams);
fatGramsSpan.textContent = Math.round(fatGrams);
carbsGramsSpan.textContent = Math.round(carbGrams);
totalCaloriesSpan.textContent = Math.round(targetCalories);
resultDiv.classList.add('show');
}