Calories in, calories out — and why it's more complicated than that

Eat less, move more. Calories in versus calories out. It's not wrong exactly — but it leaves out the part where your body has its own opinion about what those numbers mean, and that opinion is informed by years of what you've done to it.

What a TDEE calculator is actually doing

A TDEE (Total Daily Energy Expenditure) calculator estimates how many calories you need to maintain, gain, or lose weight. It takes your Basal Metabolic Rate — the calories your body burns at rest, based on your sex, height, weight, and age — and multiplies it by an activity factor to account for how much you move.

In theory this gives you a maintenance number, from which you subtract calories to lose fat or add them to build muscle. Simple. Logical. Frequently wrong.

The problem isn't the formula — it's that the formula assumes your body responds predictably to a given calorie number. It doesn't. Your body responds to what it has adapted to — and that is a very different thing.

A note on activity levels

If you do use a TDEE calculator, be conservative with the activity multiplier. Most people significantly overestimate how active they are. "Intense" exercise is genuinely intense — the kind that leaves you depleted, not just sweaty. For most people training 3–5 days a week, "moderate" or "difficult" is more accurate. The number the calculator spits out is a starting point, not a prescription.

For context: training on 2,190 calories as "moderately active" with "difficult" exercise produces a reasonable estimate. The same calculator set to "very active" and "intense" might suggest 2,500 — but if that number produces weight gain for you specifically, then for your body it isn't a maintenance figure, regardless of what the formula says.

There are people who have gained weight by decreasing their food intake, and lost fat by increasing it. A formula cannot account for that. Your body can.

Your body adapts to what you give it

How much you can eat while staying lean depends on how you have trained your body to adapt to that amount of food. This is the part no calculator captures.

Someone who has spent years eating 1,200 calories a day has, over time, trained their metabolism to function on that amount. Their body has downregulated energy expenditure, reduced hormone output, slowed recovery, and made itself as efficient as possible on minimal fuel. Eating less — even if a calculator suggests they should — often produces no fat loss and a great deal of misery.

Someone who has been eating at a reasonable intake and training consistently has a metabolism operating at a higher baseline. Their body is primed to respond to nutritional changes in a predictable way. A deficit from that baseline produces results.

Whether a specific calorie number represents a deficit or a surplus depends entirely on your unique body and its current state of adaptation. If you are not losing fat on a given number of calories, then for your body, in its current condition, that number is not a deficit — regardless of what any formula says.

How nutrition is actually built in coaching

Nutrition in my coaching process is never based on a TDEE calculator. It's based on BMR as a reference point, then adjusted around your previous dietary history, current strength level, training capacity, and body composition data.

Most times, starting calories are set at moderate if the goal is fat loss. Activity levels change from day to day, TDEE calculators tend to be generous, and starting too low leaves nowhere to go when adaptation inevitably occurs. By starting from a higher baseline, there is room to reduce calories meaningfully when it’s time for a deficit phase— rather than attempting a deficit on an intake that is already suppressed.

Then we measure the result. Body composition data, performance in the gym, hunger levels, energy, sleep — all of it informs what gets adjusted and in which direction. It is a process of informed trial and calibration, not formula application.

Food quality is not separate from this equation

Calories matter. But so does what those calories are made of. Whole, minimally processed food produces more satiety, better hormonal function, improved recovery, and more stable energy than the same calorie count from processed sources. When food quality is high, you can eat significantly more volume for the same calorie amount — which matters enormously for adherence, performance, and how your body composition responds over time.

This is why two people on the same calorie target can have completely different experiences and completely different results — if one is eating whole foods and the other isn't.

The goal is to train your body to function on as much food as possible while staying lean. The more food you can maintain on, the better a fat loss phase will be — because you are coming from a metabolically healthier place.

The goal: more food, not less

Most people come into coaching believing the goal is to eat as little as possible. It isn't. The goal is to train your body to function well on as much food as possible — building a metabolic foundation that makes every future phase, whether fat loss, maintenance, or a build, more effective and more sustainable.

Most people also need time — real time, with consistent training and structured nutrition — to understand what their actual maintenance, deficit, and surplus look like. Those numbers are not fixed. They shift as your body composition changes, your training output improves, and your metabolic health is restored. That's the process. And it works significantly better than any number a calculator can produce.