If you've ever typed "how many calories should I eat to lose weight" into Google and come back more confused than before — this post is for you.
The internet is full of contradictory advice. Some say 1200 calories. Others say never go below 1500. Fitness influencers throw around words like TDEE and BMR as if everyone already knows what they mean.
This guide cuts through all of that. By the end, you'll know exactly what a calorie deficit is, how to calculate yours, and how to use it without making yourself miserable.
What Is a Calorie Deficit, Really?
A calorie deficit happens when you eat fewer calories than your body burns in a day. That's it. No complicated science, no special diet required.
When your body doesn't get enough fuel from food, it turns to its stored energy — body fat — to make up the difference. Over time, this is what causes weight loss.
The opposite is also true. If you eat more calories than you burn, your body stores the extra energy as fat. This is a calorie surplus, and it causes weight gain.
The key number here isn't "1200 calories" or any fixed amount. It's your number — based on your body, your activity level, and your goals.
Step 1: Find Your TDEE (Total Daily Energy Expenditure)
Your TDEE is the total number of calories your body burns in a day, including exercise and everyday movement like walking to the kitchen or climbing stairs.
Think of TDEE as your maintenance calories — the amount you'd eat to stay exactly at your current weight.
TDEE is calculated from two things:
BMR (Basal Metabolic Rate) — the calories your body burns just to stay alive: breathing, pumping blood, digesting food. Even if you lay in bed all day, you'd burn this many calories.
Activity multiplier — a number that accounts for how active you are, multiplied against your BMR. Sedentary (desk job) = ×1.2, Lightly active = ×1.375, Moderately active = ×1.55, Very active = ×1.725.
Example: A 28-year-old woman, 163 cm tall, weighing 70 kg with a desk job and light exercise might have a BMR of around 1,480 calories. Multiplied by 1.375 (lightly active), her TDEE is approximately 2,035 calories per day. That's what she needs to eat to stay at 70 kg.
You don't need to calculate this manually. Apps like Calsera AI do this automatically when you set up your profile.
Step 2: Set Your Deficit
Once you know your TDEE, creating a calorie deficit is simple subtraction. A safe, sustainable deficit is 300–500 calories per day below your TDEE.
A 300-calorie deficit leads to roughly 0.3 kg (0.6 lb) loss per week. A 500-calorie deficit leads to roughly 0.5 kg (1 lb) loss per week.
This might sound slow, but it's the rate that actually sticks. Aggressive deficits (cutting 800–1,000+ calories) tend to cause muscle loss, extreme hunger, and metabolic slowdown — the triple threat that makes most diets fail.
A practical rule of thumb: never eat less than 1,200 calories per day (women) or 1,500 calories per day (men), regardless of what the math says. Going below these numbers makes it very hard to get the nutrients your body needs.
Step 3: What to Actually Eat
The biggest factor in whether a calorie deficit feels manageable or miserable is protein intake. Protein is more filling than carbs or fat, calorie for calorie. It also helps you hold on to muscle while losing fat, which keeps your metabolism from slowing down. Aim for around 1.6–2.2 grams of protein per kilogram of body weight when in a deficit.
Beyond protein, these are the foods that make a calorie deficit easy to sustain:
- Vegetables — extremely low in calories, high in fiber and volume. A large bowl of salad with protein is more filling than a small bowl of pasta with the same calorie count.
- Lean proteins — chicken breast, eggs, Greek yogurt, cottage cheese, tofu, lentils.
- Whole grains — oats, brown rice, quinoa. They digest slowly and keep you full longer than refined carbs.
- Fruit — naturally sweet, high in fiber, and much lower in calories than processed snacks.
The Biggest Mistake Beginners Make
It's not choosing the wrong foods. It's not tracking accurately. Studies consistently show that people underestimate their calorie intake by 20–40%. A handful of nuts here, a splash of olive oil there, a couple of bites off someone else's plate — it adds up to hundreds of untracked calories per day.
This is why the results feel slow even when you feel like you're eating well. You're probably eating more than you think.
An AI calorie tracker like Calsera takes a lot of friction out of this. Instead of manually searching a database for "chicken thigh, skin-on, roasted, 140g," you can just type or say what you ate and let the AI figure out the rest.
How Long Until You See Results?
Weight loss isn't linear, which trips up a lot of beginners. In the first week, you might drop 1–2 kg — but most of that is water weight from reduced carbohydrate stores, not actual fat. Then the scale might plateau for a week even though you're doing everything right. Then it drops again.
What actually matters is the trend over 4+ weeks, not what the scale says on any given morning. Weigh yourself at the same time each day (morning, after using the bathroom) and look at the weekly average rather than individual readings.
A Simple Starting Plan
If you want to put this into action today:
- Set up a calorie tracking app and enter your height, weight, age, and activity level. Let it calculate your TDEE and suggest a daily calorie goal.
- Log everything for one week — no changes to your diet yet, just observe. Most people are surprised by what they find.
- Cut 300–500 calories from your daily total, starting with the easiest wins: sugary drinks, cooking oil portions, and mindless snacking.
- Prioritize protein at every meal. Aim to hit your protein target before worrying about anything else.
- Weigh yourself daily, track weekly averages, and adjust after 3–4 weeks if the trend isn't moving.
That's it. No detox teas, no 14-day challenges, no cutting out entire food groups.
Track It Effortlessly With Calsera AI
If manual food logging sounds like too much work, Calsera AI makes it significantly easier. You describe your meal in plain English — "I had a bowl of dal bhat with a fried egg" — and the AI handles the calorie and macro estimation automatically.
It tracks your daily deficit, shows your progress toward your goal, and adjusts your targets as your weight changes. No spreadsheets, no database searching.
Download Calsera AI free on iOS and Android → calsera.app
Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult a healthcare professional before making significant changes to your diet.
Related Articles
Now that you know your calorie target, learn where those calories should come from: What Are Macros? A Beginner's Plain-English Guide to Protein, Carbs, and Fat.
The easiest way to protect your calorie deficit every morning: High Protein Breakfast for Weight Loss: 10 Easy Ideas That Keep You Full.
