Calories Explained: How to Work Out What You Need

“How many calories do I need?” is one of the most common questions we hear from people starting out at our gym in Archway. Online calculators spit out a number to the exact calorie, which makes it look like a precise science. It is not. The number you get is an educated starting point, and the real skill is adjusting it based on what your body actually does. This guide explains the idea of TDEE, how to make a sensible estimate and how to fine-tune it week by week.

What a calorie actually is

A calorie is simply a unit of energy. Everything you eat and drink, apart from water, provides some. Everything your body does, from breathing to pushing a heavy set on the chest press, uses some.

• Eat roughly the same as you use and your weight tends to stay stable.
• Eat consistently less and you tend to lose weight.
• Eat consistently more and you tend to gain weight.

Food quality, protein, sleep and training decide what that weight change is made of, muscle or fat. But the energy balance sets the direction.

What is TDEE?

TDEE stands for total daily energy expenditure. It is the total number of calories you burn in a day, and it is made up of four parts:

1. BMR (basal metabolic rate). The energy your body uses at complete rest just to stay alive. For most people, this is the biggest chunk.
2. NEAT (non-exercise activity thermogenesis). Walking to the station, taking the stairs, fidgeting, housework. This varies hugely between people.
3. Exercise. Your gym sessions, boxing, running and so on. Often smaller than people expect.
4. Thermic effect of food. The energy used to digest what you eat. Protein has the highest effect.

Your TDEE is also called your maintenance calories, the intake at which your weight holds roughly steady.

How many calories do I need? Making a first estimate

You can use an online TDEE calculator, which typically asks for age, sex, height, weight and activity level. Or you can use a rough shortcut:

• Mostly sitting, little exercise: bodyweight in kg x 26 to 29
• Moderately active, training 3 to 4 times a week: bodyweight in kg x 30 to 33
• Very active job plus regular training: bodyweight in kg x 34 or more

For example, a 75 kg person who works at a desk but trains four times a week and walks a fair bit might start around 2,250 to 2,450 calories a day.

Treat this as a guess, not a prescription. Calculators can be off by a few hundred calories either way, because they cannot see your real daily movement.

The real method: adjust using your weekly weight

This is where most people go wrong. They pick a number and stick to it no matter what. Instead, let your body give you feedback.

Step 1: Track honestly for two weeks

Eat at your estimated number and log your food as accurately as you can. Include drinks, oils, sauces and the bits you pick at while cooking.

Step 2: Weigh in under the same conditions

Weigh yourself first thing in the morning, after the toilet, before food or drink, at least three or four times a week. Daily weight jumps around because of water, salt and carbs, so work out a weekly average.

Step 3: Compare the averages

• Average stays roughly the same: you have found your maintenance.
• Average drops: your maintenance is higher than you thought.
• Average rises: your maintenance is lower than you thought.

Step 4: Adjust in small steps

Change your intake by around 100 to 200 calories a day, then give it another two weeks. Small, patient changes beat dramatic swings.

Setting a goal from your maintenance

Once you know your maintenance, you can work from it:

• Fat loss: a moderate deficit below maintenance, aiming for steady, gradual weight loss. Keep protein high and keep training hard to help hold on to muscle.
• Muscle gain: a small surplus above maintenance, aiming for slow weight gain. Our guide to bulking without getting fat covers this in more detail.
• Recomposition or maintenance: eat around maintenance and focus on training and protein.

We are not giving individual calorie targets here, because the right number depends on you. If you have a medical condition, are pregnant, have a history of disordered eating or take medication that affects appetite or weight, speak to your GP before changing your intake.

Why the numbers stop working

Many people find their progress stalls after a few months. Common reasons include:

• Portions creeping up without being tracked.
• Less daily movement, often without noticing, especially when dieting.
• Weight changing, so maintenance changes too. Re-check every few months.
• Weekend eating undoing the work done Monday to Friday.

Getting a plan built around you

Counting calories is a skill, and it is far easier with someone checking in each week. Our Body Transformation coaching includes personalised nutrition and weekly check-ins, so your numbers are adjusted from real data rather than guesswork.

FAQs

How many calories do I need to lose weight?

It depends on your maintenance. Find that first, then eat moderately below it and adjust based on your weekly average weight.

Are TDEE calculators accurate?

They give a reasonable starting estimate but can be off by a few hundred calories. Your weekly weight trend is the real test.

Do I need to count calories forever?

No. Many people track for a period to learn portion sizes, then move to a more relaxed approach.

Do I burn lots of calories in the gym?

Less than most people think. Weight training is brilliant for building muscle, but daily movement and diet usually have a bigger effect on energy balance.

Talk to a coach

Want help working it out properly? Meet our coaches, Ian, Alberto and Artem, and ask about 1-2-1 training. We are a few minutes from Archway station, with easy access from Holloway, Highgate and Tufnell Park.