How I Used TDEE to Transform My Body at University (And What I Wish I'd Known Sooner)

Let me be honest with you: the "Freshman 15" is very real — and for me, it was actually Freshman 17.

When I started university, everyone around me joked about gaining weight in the first year. I heard it at orientation. I heard it in the dorms. I brushed it off every time.

By the end of my first year, I had gained 17 pounds (8 kilograms) of body weight. Not 15 — 17.

And the worst part? I didn't even have many photos from that period because my self-confidence was so low. What I do know is that the main reason I ended up in that unhealthy state wasn't laziness or lack of effort. It was a lack of knowledge — specifically, I had no idea how to:

• Calculate how many calories my body actually needed
• Understand the relationship between food, exercise, and weight
• Build a sustainable mindset around fitness

The one concept that changed everything for me was learning about Total Daily Energy Expenditure (TDEE). Once I understood this, I went to the gym for four years straight and transformed both my body and my mindset. This post covers everything I wish someone had told me in my first week of university.

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What Is Total Daily Energy Expenditure (TDEE)?

Total Daily Energy Expenditure is an estimation of how many calories your body burns per day when exercise is taken into account.

Think of it this way: your body is constantly spending energy — to breathe, to pump blood, to move, to digest food. TDEE captures all of that, including the extra calories you burn from intentional exercise.

The core principle of weight management comes down to this simple equation:

To maintain weight: Calories In = Calories Out
To lose weight: Calories In < Calories Out
To gain weight (muscle building): Calories In > Calories Out

By "calories in," I mean the food and nutrients you consume. By "calories out," I mean your TDEE — your total daily energy burned. Understanding this relationship is the foundation of every effective diet and fitness plan.

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How to Calculate Your TDEE

You can calculate your TDEE using a free online calculator — I personally used tdee.tech (the site you're on right now) during my own fitness journey.

Here's exactly what you'll need to enter:

• Sex (affects your basal metabolic rate)
• Age
• Current weight
• Height
• Activity level — this is important to get right

For activity level, be honest. I was going to the gym five days a week and walking approximately 10,000 steps on my other two days, so I selected "3–5 days of moderate exercise." If you overestimate your activity, your maintenance calories will be inflated and you'll eat more than you actually burn.

Once you enter your details, the calculator will show you:

• Maintenance calories — the number of calories to eat if you want to stay at your current weight
• Cutting calories — a calorie target with a deficit built in to help you lose weight
• Bulking calories — a calorie surplus for muscle gain

For example, at my current stats, my maintenance is approximately 2,062 calories per day (about 14,433 per week).

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Understanding the 500-Calorie Deficit Rule

One of the most practical things the TDEE calculator shows you is the cutting target, which is typically set at a 500-calorie deficit below your maintenance.

Why 500 calories? Because one pound of body fat stores roughly 3,500 calories of energy. A 500-calorie daily deficit means you're burning through approximately 3,500 extra calories per week — which translates to about 0.5 kg (1 lb) of fat loss per week.

For me, this meant a cutting target of 1,562 calories per day — a realistic, sustainable number that doesn't leave you starving.

This is just a starting point. In your first few weeks, pay attention to:

• Are you actually losing weight?
• Do you feel excessively hungry or low on energy?
• Is your workout performance declining?

If the deficit feels too aggressive, add 100–200 calories back. If you're not losing weight after 2–3 weeks, reduce slightly. Your body is unique — the calculator gives you the best estimate, but you have to verify it against real-world results.

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What About Macronutrients?

Once you know your total calorie target, the next step is understanding macronutrients — protein, carbohydrates, and fat — and how much of each you need.

The TDEE calculator breaks this down for you automatically in three different ratios:

Personally, I follow a moderate carb approach. Cutting carbs completely has never been sustainable for me — I love carbs, and I know that a balanced diet covering all three macros works best for my body and lifestyle.

For my cutting calories (1,562 cal/day), my moderate carb breakdown is roughly:

• Protein: 117g
• Fat: 61g
• Carbohydrates: 137g

If you're just starting out, I'd recommend using the calculator's macronutrient breakdown as a roadmap. Try it for 4–6 weeks, see how your body responds, and then adjust from there.

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A Note on BMI

When you use the TDEE calculator, you'll also see your BMI (Body Mass Index) score. While this is a useful general reference, it has limitations — it doesn't account for muscle mass, body composition, or other individual factors.

A person with a lot of muscle mass can have a "high" BMI without carrying excess fat. So while BMI is one data point worth knowing, it shouldn't be the only metric you track. I'll write a separate post diving deeper into how to interpret BMI in the context of a real fitness journey.

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How to Actually Hit Your Calorie Targets Every Day

Knowing your TDEE is step one. The harder part is being accountable to it daily.

The tool that helped me the most — and that most of my university friends also used — was MyFitnessPal. I tracked my food consistently with this app for two years straight, and it genuinely transformed how I thought about food.

The process is straightforward:

1. Log everything you eat (yes, even small snacks)
2. Compare your logged calories to your TDEE target
3. Adjust portion sizes or food choices to hit your goal

If you'd like a detailed walkthrough of how I used MyFitnessPal effectively alongside my TDEE targets, let me know in the comments — I'm happy to put together a full demo post.

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Key Takeaways

• TDEE is the total number of calories your body burns per day, including exercise
• To lose weight, you need to eat fewer calories than your TDEE (a deficit)
• A 500-calorie daily deficit leads to approximately 0.5 kg of weight loss per week
• Use the TDEE calculator to find your personal maintenance and cutting targets
• Track your macronutrients — protein, carbs, and fat — not just total calories
• Use a food tracking app like MyFitnessPal to stay accountable

The biggest mistake I made in my first year of university was not knowing this. Once I understood TDEE and started tracking my intake against it, everything changed — mentally and physically.

Calculate your TDEE today and take the first step toward understanding your body.