Key takeaways
- Estimate maintenance calories with a standard formula and an activity multiplier. Treat the answer as a starting guess.
- A moderate deficit of roughly 300 to 500 calories a day suits most men.
- Your weekly average weight over two to three weeks tells you your real maintenance better than any calculator.
- Very low intakes need medical supervision. More restriction isn't better.
In this guide
A calorie deficit is the engine of fat loss: consistently eating a bit less energy than your body uses. But how much less? And how do you work out what your body uses in the first place?
Prefer not to do the maths? Our calorie deficit calculator does it for you. This guide walks you through a simple, three-step process: estimate your maintenance calories, choose a moderate deficit, and then adjust based on what actually happens. You don't need to count calories forever. Many people use this process for a few weeks to learn, then switch to simpler habits. See the beginner fat-loss guide for both approaches.
Step 1: Estimate your maintenance calories
Your maintenance calories are roughly the amount you'd need to eat to keep your weight stable. They're made up of your basal metabolic rate (the energy your body uses at rest) plus everything you do on top of that.
Estimate your basal metabolic rate (BMR)
A commonly used formula for men is the Mifflin–St Jeor equation:
BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age in years) + 5
Example: a 35-year-old man who weighs 90 kg and is 180 cm tall:
- 10 × 90 = 900
- 6.25 × 180 = 1,125
- 5 × 35 = 175
- BMR = 900 + 1,125 − 175 + 5 = 1,855 calories
Multiply by an activity factor
| Activity level | Description | Multiplier |
|---|---|---|
| Sedentary | Desk job, little walking, no exercise | × 1.2 |
| Lightly active | Some walking, 1–3 workouts per week | × 1.375 |
| Moderately active | Regular walking, 3–5 workouts per week | × 1.55 |
| Very active | Physical job or hard daily training | × 1.725 |
Continuing the example, a lightly active man: 1,855 × 1.375 ≈ 2,550 calories per day estimated maintenance.
Most people overestimate their activity. If you're unsure between two levels, choose the lower one.
Step 2: Choose a moderate deficit
A moderate deficit is enough to make steady progress without the hunger, fatigue and muscle loss that come with crash dieting. For most men, that's roughly 300 to 500 calories below maintenance per day.
In the example: 2,550 − 300 to 500 = about 2,050 to 2,250 calories per day.
A useful cross-check is the rate of loss. A commonly recommended pace is about 0.5% to 1% of body weight per week on average. For a 90 kg man, that's roughly 0.45 to 0.9 kg per week. If you have a lot of body fat to lose, you may be toward the upper end at first. If you're already fairly lean, or you want to build chest muscle while losing fat, a smaller deficit is usually better.
Step 3: Adjust using real results
Calculators are estimates. Your actual maintenance could be a few hundred calories higher or lower than any formula suggests. The fix is to let your results guide you:
- Eat your target consistently for two to three weeks.
- Weigh yourself several mornings a week under the same conditions and calculate a weekly average.
- Measure your waist every one to two weeks.
- Compare the trend with your target pace.
| What you see after 2–3 weeks | What to do |
|---|---|
| Losing about 0.5–1% per week, waist coming down | Keep going |
| No change in weekly average or waist | Reduce by 100–200 calories, or add 1,000–2,000 daily steps |
| Losing faster than 1% per week, feeling drained, strength dropping | Increase by 100–200 calories |
| Weight flat but waist shrinking and strength rising | Probably recomposition. Keep going |
Remember that the first week often shows a bigger drop, largely from water and stored carbohydrate. See water weight vs fat loss. Judge your pace from weeks two and three onward.
Making your target easier to hit
A number on its own doesn't create a deficit. Habits do. These make your target easier to live with:
- Protein at every meal, around 1.6 g per kg of body weight per day. See how much protein you need.
- Plenty of vegetables, fruit and fibre for volume and fullness.
- Fewer liquid calories, especially sugary drinks and alcohol.
- Consistent meal times rather than grazing.
- Planned meals for busy days. See meal prep for fat loss.
Tracking tips
If you track with an app for a while (see how to count calories without obsessing for the full method):
- Weigh foods with a kitchen scale for a week or two. Estimates of portion size are often far off.
- Log cooking oils, sauces and drinks. They're the most commonly missed calories.
- Don't chase perfection. Being roughly right most days beats being exact for three days and then quitting.
- Don't eat back exercise calories. Fitness trackers often overestimate what you burn.
When your deficit needs to change
As you lose weight, your maintenance calories fall, because a smaller body uses less energy. Eventually your deficit shrinks and progress slows. When that happens, repeat Step 3: look at your trend and make a small adjustment. Fat-loss plateaus covers this in detail.
After several months of dieting, a planned period of one to two weeks at maintenance can make the next phase easier.
When you reach your goal, how to maintain weight loss explains how to move to maintenance.
The bottom line
Estimate your maintenance with a formula, subtract a moderate 300 to 500 calories, then let your weekly averages tell you the truth and adjust in small steps. Combine it with protein, strength training, walking and sleep, and you have a plan you can keep for months. For the food side, see nutrition fundamentals.
Free printable resource
Put this into practice: the free 7-day starter checklist
Seven practical days covering your baseline, nutrition setup, a simple beginner workout, daily movement and a review. It comes with a grocery checklist, habit tracker, progress sheet and a planner for the next 30 days.
Free, printable and no sign-up needed right now.
How this guide was written
Written by the LoseManBoobs7 editorial team using established public-health guidance and peer-reviewed research, following our editorial policy and health content policy. It has not been individually reviewed by a medical professional. Last reviewed . Spotted an error? Tell us.