TDEE Explained Simply: How Many Calories to Lose or Gain Weight

The first question anyone asks when they want to lose or gain weight is: "How much should I eat?" The answer lives in a number called TDEE, your total daily energy expenditure. With TDEE explained simply, you'll know roughly how many calories your body burns on a normal day. Once you know that number, setting up a diet to lose fat, maintain your weight or build muscle stops being guesswork and becomes a plan you can follow and adjust.

What is TDEE and what is it made of?

TDEE stands for Total Daily Energy Expenditure: all the energy your body uses in 24 hours. It has four main parts:

• Basal metabolic rate (BMR): the energy needed to stay alive at complete rest, running your heart, brain, breathing and body temperature. For most people it makes up about 60 to 70 percent of TDEE.
• Thermic effect of food (TEF): energy spent digesting and absorbing food, about 10 percent of intake. Protein has the highest thermic effect.
• Non-exercise activity (NEAT): walking, housework, standing, taking stairs and even fidgeting. This part varies enormously between people.
• Exercise (EAT): calories burned in gym sessions, running or swimming.

Interestingly, NEAT often matters more than formal exercise. Someone who trains one hour a week but sits at a desk the rest of the day may burn fewer calories than someone who never goes to the gym but has an active, on-their-feet job.

Step one: calculate your BMR

The most accurate simple formula for adults is the Mifflin-St Jeor equation. Weight goes in kilograms, height in centimetres and age in years:

• Men: BMR = (10 × weight) + (6.25 × height) − (5 × age) + 5
• Women: BMR = (10 × weight) + (6.25 × height) − (5 × age) − 161

This formula gives a good estimate for most people, but it may underestimate needs for very muscular athletes and slightly overestimate them for people with high body fat. Treat it as a starting point, not a final verdict.

Step two: choose an activity factor

To move from BMR to TDEE, multiply BMR by an activity factor. Be honest here; most people overestimate how active they are.

If you'd rather not do the maths by hand, the ProGym calorie calculator runs these steps automatically and shows your BMI as well.

Two worked examples

Example 1: a 30-year-old man

Ali is 30, 178 cm tall, weighs 80 kg and trains four times a week.

1. BMR = (10 × 80) + (6.25 × 178) − (5 × 30) + 5 = 800 + 1112.5 − 150 + 5 ≈ 1,770 kcal
2. Moderately active factor: 1.55
3. TDEE ≈ 1,770 × 1.55 ≈ 2,740 kcal

So if Ali eats around 2,700 to 2,800 kcal a day, his weight should stay roughly stable.

Example 2: a 28-year-old woman

Maryam is 28, 163 cm tall and weighs 65 kg. She works in an office and goes for brisk walks twice a week.

1. BMR = (10 × 65) + (6.25 × 163) − (5 × 28) − 161 = 650 + 1018.75 − 140 − 161 ≈ 1,370 kcal
2. Lightly active factor: 1.375
3. TDEE ≈ 1,370 × 1.375 ≈ 1,880 kcal

How much to eat to lose weight

To lose weight you need to eat below your TDEE. A moderate deficit of 300 to 500 kcal, or about 15 to 20 percent below TDEE, gives most people the best balance between steady progress and keeping muscle.

• Ali could eat around 2,250 to 2,400 kcal per day to lose fat.
• Maryam could aim for about 1,450 to 1,600 kcal per day.

A very large deficit, such as eating 1,000 kcal a day, leads to constant hunger, fatigue, poor training performance, muscle loss and, eventually, weight regain. The leaner you are, the gentler the deficit should be. For ideas on lower-calorie menus built on familiar food, browse the other articles in the ProGym magazine.

How much to eat to gain weight and build muscle

To gain weight you must eat above your TDEE, but "more" doesn't mean "anything". For muscle gain with minimal extra fat, a surplus of 200 to 300 kcal per day is enough. People who are very thin or struggle to gain can try a surplus of 400 to 500 kcal.

A reasonable target for most people is gaining about 0.25 to 0.5 percent of body weight per week. For a 60 kg person that's roughly 150 to 300 grams per week. If you're gaining faster than that, a good share of it is probably fat.

Splitting calories into protein, fat and carbs

Once your calorie target is set, the next step is dividing it between macronutrients:

1. Protein: about 1.6 to 2.2 grams per kilogram of body weight. Each gram has 4 kcal.
2. Fat: about 20 to 35 percent of total calories, and ideally not below 0.6 grams per kilogram. Each gram has 9 kcal.
3. Carbohydrates: the remaining calories, your main training fuel. Each gram has 4 kcal.

For Ali on 2,300 kcal during a fat-loss phase, that could be 160 g protein (640 kcal), 65 g fat (about 585 kcal) and the rest, around 270 g, from carbohydrates (about 1,075 kcal).

Why the formula differs from reality, and how to adjust

Every formula is an estimate. Genetics, muscle mass, sleep quality, stress and how accurately you log food all affect the result. The best approach is to test your calculated number for two to three weeks and adjust based on your real weight trend:

• Weigh yourself every morning after using the bathroom and before eating, and use the weekly average, not a single day.
• If your goal is fat loss and your average hasn't moved after two weeks, cut 150 to 200 kcal per day or increase your daily steps.
• If your goal is weight gain and the scale is flat, add 150 to 200 kcal.
• Track your waist measurement and take monthly photos; sometimes the scale stalls while body composition improves.

As you lose weight, your TDEE drops a little too, because a smaller body uses less energy. Recalculate after every 4 to 5 kg of weight loss.

Safety notes

If you have an underlying condition such as diabetes, thyroid problems, kidney or heart disease, are pregnant or breastfeeding, or have a history of eating problems, speak with a physician or registered dietitian before making major changes to your calorie intake. Growing teenagers should not follow low-calorie diets without professional supervision.

Summary

Calculating your TDEE takes three simple steps: work out BMR with the Mifflin-St Jeor formula, multiply it by an honest activity factor, then subtract 300 to 500 kcal or add 200 to 300 kcal depending on your goal. After that, fine-tune the number using your weekly weight average. This simple, measurable method saves you from harsh, baseless diets. If you want your nutrition and training to work together, sign up for ProGym and track your progress step by step.

Frequently asked questions