How Many Calories Should I Eat a Day to Lose Weight?
"How many calories should I eat to lose weight?" is the most common question in the fitness industry. The diet industry makes billions selling complicated meal plans, detoxes, and supplements, but weight loss ultimately comes down to basic thermodynamics. In this guide, we will cut through the noise and explain exactly how to calculate your daily calorie target for safe, sustainable fat loss.
Find Your Exact Target
Don't do the math by hand. Use our free calorie deficit calculator to instantly find your exact daily weight loss calories.
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The Science of Weight Loss
Weight loss is governed by the First Law of Thermodynamics: energy cannot be created or destroyed, only transformed. In the context of the human body, this means that if you consume less energy (calories) than you expend, your body is forced to break down stored energy (body fat) to make up the difference. This is called a calorie deficit.
There is no magic diet that can bypass this law. Whether you eat Keto, Vegan, Paleo, or Carnivore, you will only lose weight if you are in a calorie deficit.
Finding Your Maintenance Calories (TDEE)
Before you can figure out how many calories to cut, you need to know how many calories you burn. This is your Total Daily Energy Expenditure (TDEE). Your TDEE is made up of your Basal Metabolic Rate (the calories you burn at rest) plus your daily activity and exercise.
If you eat exactly your TDEE every day, your weight will stay exactly the same. To find your TDEE, you can use the Mifflin-St Jeor formula, or simply plug your stats into our calorie deficit calculator.
The 500-Calorie Rule
One pound of human body fat contains approximately 3,500 calories of stored energy. Therefore, to lose 1 pound of fat per week, you need to create a deficit of 3,500 calories over the course of that week. Divided by 7 days, that equals a daily deficit of 500 calories.
For example, if your TDEE is 2,500 calories, you would eat 2,000 calories a day to lose 1 pound a week. If you want to lose 2 pounds a week (the maximum recommended safe rate), you would subtract 1,000 calories, eating 1,500 calories a day.
Tracking Your Progress?
The scale can fluctuate due to water weight. Track your true fat loss using our body fat calculator and BMI calculator.
Why You Shouldn't Eat Below Your BMR
You might think, "If a 500-calorie deficit is good, a 1,500-calorie deficit is great!" This is a dangerous trap. Your BMR (Basal Metabolic Rate) is the energy your body needs just to keep your heart beating and lungs breathing at rest.
If you eat below your BMR, your body panics. It thinks you are starving and begins a process called metabolic adaptation. It will break down your muscle tissue for energy (since muscle burns more calories) and slow down your thyroid function to conserve energy. You will feel sluggish, cold, and irritable, and your weight loss will completely stall.
As a general rule, women should not eat fewer than 1,200 calories a day, and men should not eat fewer than 1,500 calories a day without medical supervision.
Do Macros Matter?
While a calorie deficit dictates *how much* weight you lose, your macronutrients (protein, carbs, fat) dictate *what* you lose. If you eat a low-protein diet, a large portion of the weight you lose will be muscle, not fat.
To ensure you are losing fat and preserving muscle, you should prioritize protein. If you prefer a low-carb approach to dieting, you can use our keto macro calculator to find the exact ratio of fats and proteins to keep you satiated while in a deficit.
Frequently Asked Questions (FAQ)
How many calories should I eat a day to lose 1 pound a week?
To lose 1 pound a week, you need to create a daily calorie deficit of 500 calories. You can do this by eating 500 calories less than your TDEE, or by eating 250 calories less and burning 250 calories through exercise.
Is it safe to eat 1200 calories a day?
For many people, 1200 calories is below their Basal Metabolic Rate (BMR), meaning it is not enough energy to keep their organs functioning properly at rest. Eating below your BMR can slow your metabolism and cause muscle loss. Always calculate your BMR first.
Can I lose weight without counting calories?
Yes, but it is harder. You can lose weight by reducing portion sizes, cutting out sugary drinks, and increasing protein intake (which makes you feel full). However, counting calories is the most accurate way to ensure you are in a deficit.