Diet Comparison Calculator

TDEE stands for Total Daily Energy Expenditure — the number of calories your body burns each day based on your age, gender, height, weight, and activity level. It's the baseline that determines whether a diet puts you in a caloric deficit (weight loss), surplus (weight gain), or maintenance. Comparing your diet's calorie targets against your TDEE reveals how each plan will affect your body weight over time.

The calculator subtracts your TDEE from each diet's daily calorie target to find the daily caloric surplus or deficit. This is then multiplied by 7 (days per week) and divided by 7,700 — the approximate number of calories in 1 kg of body fat — to estimate weekly weight change. A negative number means projected weight loss; a positive number means projected gain.

Macronutrients are the three main energy-providing nutrients: protein (4 kcal/g), carbohydrates (4 kcal/g), and fat (9 kcal/g). Beyond total calories, your macro split affects muscle retention, energy levels, hunger, and metabolic health. Comparing macro grams across diets helps you understand the nutritional differences, not just the calorie differences.

Ideally yes — your protein, carb, and fat percentages for each diet plan should sum to 100% to reflect a realistic diet. The calculator will still run if they don't perfectly add up, but the gram values shown will be proportional to the percentages you entered. For the most accurate comparison, make sure each diet's three macro percentages total 100.

This calculator uses the Mifflin-St Jeor equation, which is widely regarded as the most accurate formula for estimating Basal Metabolic Rate (BMR) in the general population. Your BMR is then multiplied by an activity factor corresponding to your selected activity level to arrive at your TDEE.

This tool supports up to three diet plans simultaneously, which covers the most common comparison scenarios — for example, Keto vs. Mediterranean vs. High Protein. To compare more plans, simply adjust the inputs with different diet configurations and note the results.

The projections are estimates based on the 3,500-calorie-per-pound (7,700 kcal/kg) rule, which is a well-established simplification used in nutrition science. Real-world weight change is also influenced by water retention, metabolic adaptation, hormones, and food composition. Use these numbers as directional guidance rather than precise predictions.

A commonly recommended balanced macro split is approximately 20–30% protein, 45–55% carbohydrates, and 25–35% fat. This aligns with dietary guidelines from organisations like the WHO and USDA. However, the optimal split varies by individual goals — athletes may need more protein, while low-carb dieters intentionally shift fat higher.