Estimate your potential weight loss on a ketogenic diet.
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 details to see your estimated weight loss.
Understanding the Keto Weight Loss Calculator
The ketogenic diet is a low-carbohydrate, high-fat diet that shifts the body's metabolism from using glucose for energy to using ketones, which are produced from the breakdown of fats. This metabolic state is known as ketosis. Many people adopt this diet for weight loss due to its potential to increase fat burning and reduce appetite.
This calculator provides an ESTIMATE of potential weight loss on a ketogenic diet. It's important to understand that individual results can vary significantly based on numerous factors, including adherence to the diet, individual metabolism, underlying health conditions, genetics, and lifestyle. This tool is for informational purposes only and should not be considered medical advice. Always consult with a healthcare professional before making significant dietary changes.
How it Works (Simplified Model):
This calculator uses a simplified approach to estimate potential weight loss. It considers your current and target weight, body fat percentage, and activity level to estimate your Basal Metabolic Rate (BMR) and Total Daily Energy Expenditure (TDEE). The keto diet's effect on appetite suppression and metabolic changes is approximated to estimate a caloric deficit.
Basal Metabolic Rate (BMR): The number of calories your body burns at rest. We use a modified Harris-Benedict equation for this.
Total Daily Energy Expenditure (TDEE): BMR multiplied by an activity factor.
Caloric Deficit: On a keto diet, appetite is often reduced, leading to a natural reduction in calorie intake. This calculator assumes a modest deficit that encourages sustainable fat loss.
Fat Loss Estimation: It's estimated that approximately 7,700 calories equal 1 kg of fat. The calculator projects how long it might take to reach your target weight based on the estimated daily deficit.
Input Explanations:
Current Weight (kg): Your current body weight in kilograms.
Target Weight (kg): The weight you aim to achieve.
Current Body Fat (%): The estimated percentage of your body weight that is fat. This helps differentiate between fat loss and lean mass loss.
Activity Level: Your general level of physical activity, which influences your TDEE.
Important Considerations:
Initial Water Weight Loss: In the first week or two of a keto diet, significant weight loss is often due to water loss as glycogen stores deplete. This calculator focuses on fat loss over a longer period.
Muscle Mass: While the goal is fat loss, it's crucial to preserve muscle mass. Adequate protein intake and resistance training are essential.
Electrolyte Balance: The keto diet can deplete electrolytes, so proper hydration and mineral intake are vital.
Sustainability: Long-term adherence depends on individual preferences and how well the diet fits into your lifestyle.
Use this calculator as a guide to understand the potential journey of weight loss on a ketogenic diet. Remember consistency, patience, and professional guidance are key to achieving your health goals.
function calculateKetoLoss() {
var currentWeight = parseFloat(document.getElementById('currentWeight').value);
var targetWeight = parseFloat(document.getElementById('targetWeight').value);
var bodyFatPercentage = parseFloat(document.getElementById('bodyFatPercentage').value);
var activityLevel = document.getElementById('activityLevel').value;
var resultDiv = document.getElementById('result');
// — Input Validation —
if (isNaN(currentWeight) || isNaN(targetWeight) || isNaN(bodyFatPercentage)) {
resultDiv.innerHTML = "Please enter valid numbers for weight and body fat.";
return;
}
if (currentWeight <= 0 || targetWeight <= 0 || bodyFatPercentage 100) {
resultDiv.innerHTML = "Please enter realistic values.";
return;
}
if (targetWeight >= currentWeight) {
resultDiv.innerHTML = "Target weight must be less than current weight for loss calculation.";
return;
}
// — BMR Calculation (Mifflin-St Jeor Equation – commonly used and relatively accurate) —
// For simplicity and wider applicability, we'll use a generic input for gender or assume a default average.
// A more complex calculator might ask for gender and age. For this example, we'll omit them for simplicity.
// Let's assume a simplified BMR calculation for demonstration, or use a typical value.
// A common approximation: BMR is roughly 10 * weight(kg) for women, 11 * weight(kg) for men.
// For a more standard approach, we'll use a placeholder that reflects TDEE directly.
// — Activity Level Multipliers —
var activityMultiplier;
switch (activityLevel) {
case 'sedentary':
activityMultiplier = 1.2;
break;
case 'lightly_active':
activityMultiplier = 1.375;
break;
case 'moderately_active':
activityMultiplier = 1.55;
break;
case 'very_active':
activityMultiplier = 1.725;
break;
case 'extra_active':
activityMultiplier = 1.9;
break;
default:
activityMultiplier = 1.375; // Default to lightly active
}
// — TDEE Estimation —
// A common simplified TDEE estimate is around 15-20 calories per pound of body weight, or ~33-44 calories per kg.
// For a more structured approach without full BMR formula:
// We'll directly estimate TDEE based on weight and activity.
// A rough TDEE calculation might be: BMR * multiplier.
// Let's use a proxy for BMR for simplicity here, as gender/age are omitted:
var estimatedBMR = currentWeight * 31; // This is a rough average, assuming ~31 kcal/kg for BMR
var tdee = estimatedBMR * activityMultiplier;
// — Keto Diet Caloric Deficit Assumption —
// Keto diets are known for appetite suppression, leading to a potential natural caloric deficit.
// Let's assume a moderate deficit of 500-750 calories per day, as this is often sustainable.
var dailyCaloricDeficit = 600; // Average of 500-700
// — Weight Loss Calculation —
var weightToLose = currentWeight – targetWeight;
var fatPerKg = 7700; // Approximate calories in 1 kg of fat
var totalCaloriesToLose = weightToLose * fatPerKg;
var estimatedDaysToLose = totalCaloriesToLose / dailyCaloricDeficit;
var estimatedWeeksToLose = estimatedDaysToLose / 7;
// — Display Results —
var resultHTML = "Estimated weight to lose: " + weightToLose.toFixed(1) + " kg. ";
resultHTML += "Estimated time to reach target: ";
if (estimatedWeeksToLose < 4) {
resultHTML += estimatedDaysToLose.toFixed(0) + " days.";
} else if (estimatedWeeksToLose < 52) {
resultHTML += estimatedWeeksToLose.toFixed(1) + " weeks.";
} else {
var estimatedYearsToLose = estimatedWeeksToLose / 52;
resultHTML += estimatedYearsToLose.toFixed(1) + " years.";
}
resultDiv.innerHTML = resultHTML;
}