Energy balance is the difference between the calories you eat and the calories you burn, and fat loss happens when that balance sits in a modest deficit, often around 300 to 500 calories a day, for weeks at a time. Mr PT Fitness is a private home studio in Dee Why run by Matt Reilly, a personal trainer with 10+ years' experience. No diet style gets around energy balance for fat loss. Low carb, intermittent fasting and "clean eating" all work, when they work, by making it easier to eat a little less.
What is energy balance?
Energy balance is the relationship between the energy you take in from food and drink and the energy your body uses to stay alive, digest food and move. Eat more than you use and the surplus is stored, mostly as body fat. Eat less and the body draws on those stores to cover the gap.
The "energy out" side has four parts. The biggest is your resting metabolism, the energy needed just to keep you running, which is usually 60 to 70% of the daily total. Then comes digesting food, planned exercise, and everything else you do on your feet: walking to the car, standing at the kitchen bench, taking the stairs. That last category is called non-exercise activity, and for most people it burns more across a day than the workout does.
Australian food labels list energy in kilojoules rather than calories. To convert, divide kilojoules by 4.2. A 2,000kJ meal is roughly 480 calories.
Do calories in vs calories out still decide fat loss?
Yes. Across weeks and months, a sustained energy deficit is what drives fat loss, and no food, timing trick or eating style has been shown to get around it. What diets change is how easy the deficit is to hold, not whether one is needed.
That does not mean every calorie behaves identically once eaten. The table shows why a plate of chicken and vegetables and a bag of chips with the same calorie count feel very different by 3pm.
| Source | Energy per gram | Energy used to digest it | How full it tends to keep you |
|---|---|---|---|
| Protein | 4 calories (17kJ) | Roughly 20 to 30% of its calories | High |
| Carbohydrate | 4 calories (17kJ) | Roughly 5 to 10% | Moderate, higher when high in fibre |
| Fat | 9 calories (37kJ) | Roughly 0 to 3% | Moderate, easy to overeat |
| Alcohol | 7 calories (29kJ) | Varies | Low, and it tends to loosen food choices |
On paper, a daily deficit of 500 calories adds up to around 3,500 a week, which is roughly 0.4 to 0.5kg of fat. In practice the rate is usually a little slower, because the body adjusts as you get lighter and most people move slightly less when eating less.
Where do calories get miscounted?
Most miscounting happens in the foods that do not feel like meals: cooking oil, milky coffees, drinks, handfuls of snacks and weekends. Research on food diaries consistently finds that people under-report what they eat, and the gap is rarely in the chicken breast.
- Cooking oil: one tablespoon of olive oil is about 120 calories, and a free pour is often two or three
- Coffee: a large full-cream flat white can be around 150 to 200 calories. Two a day is a small meal
- Drinks: a standard glass of wine is roughly 100 to 130 calories and a schooner of full-strength beer around 150 to 200
- Tastes and leftovers: the crusts off the kids' toast and the last spoonful from the pan rarely get counted
- Weekends: the pattern we see most often at the Dee Why studio is a tight Monday to Thursday and a loose Friday to Sunday. Two 800-calorie surplus days can cancel most of a week's deficit
None of these foods are off limits. The point is that they are where the maths quietly goes missing, so they are the first place to look when progress stalls.
Want a second set of eyes on your week?
Free 15-minute consult at the Dee Why studio to look at where your energy balance is actually landing and what to change first. Book here or call 0422 745 334.
Why can the same deficit feel different for different people?
Because two people eating the same number of calories can differ in body size, daily movement, sleep, stress and food choices, and each of those changes how hungry a deficit makes you. The energy maths is the same. The experience of living inside it is not.
Non-exercise activity is the biggest variable. It can differ by several hundred calories a day between two people of similar size, which is why an office worker from Collaroy and a tradie from Brookvale can eat the same lunch and get very different results. Short sleep is associated with higher appetite the next day, and a deficit built on low-protein, low-fibre food tends to feel much harder than one built on meals that keep you full.
Scale weight also moves for reasons that have nothing to do with fat. Water, salt, carbohydrate intake and hormonal cycles can shift the number by 1 to 2kg day to day, which can hide a real deficit for a week or two. Judging progress by waist measurement, photos and how clothes fit gives a clearer picture, covered in how to track progress without the scales.
If you are eating less, moving more and nothing has changed after a month or more, or if you have a medical condition, are pregnant, or have a history of disordered eating, speak to your GP or an Accredited Practising Dietitian before cutting further. A personal trainer can give general guidance, but individual medical nutrition sits with them.
How do you create a calorie deficit without tracking obsessively?
Build a small number of repeatable habits that lower intake or raise activity automatically, then check the trend every three to four weeks instead of counting every meal. For most people this holds far longer than logging everything, because it survives a busy week.
- Anchor each meal with protein: it is the most filling of the three macronutrients and uses the most energy to digest
- Fill half the plate with vegetables: high volume, high fibre, low energy
- Keep portions consistent: the same bowl and the same serving spoon make intake predictable without weighing it
- Drink water first: swapping one daily soft drink, juice or second milky coffee is often 150 to 250 calories on its own
- Walk more: adding 3,000 daily steps is usually around 100 to 150 calories, and the Dee Why lagoon loop makes that easy
- Track briefly, not forever: one or two weeks of honest logging every few months shows where the extra energy is hiding, then you stop
Avoid very aggressive deficits. They tend to cost muscle, sleep and training quality, and they are much harder to sustain than a moderate one. If you want structure without the spreadsheet, the personal trainer nutrition plan explains what a general plan within PT scope covers. It pairs with 1-on-1 training from $50 per session, listed under services.
General information, not individual medical or dietary advice. See your GP or an Accredited Practising Dietitian (APD) for your situation.
Frequently asked questions
Is a calorie a calorie?
For fat loss, mostly yes. A calorie is a unit of energy, so 500 calories of chocolate and 500 calories of chicken carry the same amount. What differs is how full each keeps you, how much energy digestion uses, and how easy each is to overeat. That is why food choice still matters even though total intake decides the result.
Do I have to count calories to lose fat?
No. Counting is one way to create a deficit, not a requirement for one. Many people lose fat by eating protein at each meal, keeping portions consistent, cutting liquid calories and walking more. A short spell of tracking can still help when progress stalls, because it shows where the extra energy is coming from.
Why am I not losing weight in a calorie deficit?
Usually because the deficit is smaller than it looks. Cooking oils, drinks, snacks and weekends are commonly under-counted, and daily water shifts of 1 to 2kg can hide real fat loss for a week or two. Judge progress over three to four weeks. If nothing has moved after that, see your GP to rule out a medical cause.
Make the deficit easy to hold
Free 15-minute consult. We will look at your week, find where the energy is going, and set up training and eating habits you can keep on the Northern Beaches long term.