How Many Calories to Lose Weight Safely
5 min read
Weight loss comes down to a sustained calorie deficit — taking in less energy than you burn over time. The practical questions are how big a deficit to choose, how low is too low, and how to keep going when the scale stops cooperating.
Start from maintenance
You cannot set a deficit without knowing your maintenance calories (TDEE). Get a first estimate from the TDEE calculator, then subtract. If your estimate has not been calibrated against a few weeks of real data, treat it as approximate — see how TDEE works.
How big a deficit
The common target is about 500 calories per day below maintenance, which trends toward roughly 0.5 kg (1 lb) of weight loss per week. That figure comes from the rough estimate that a kilogram of stored body fat holds about 7,700 calories (a pound holds about 3,500).
| Daily deficit | Approx. weekly loss | Trade-off |
|---|---|---|
| 250 | ~0.25 kg | Easiest to sustain, gentle on training and mood; good if you have less to lose |
| 500 | ~0.5 kg | The standard middle ground for most people |
| 750–1,000 | ~0.75–1 kg | Faster, but more hunger, fatigue, and muscle-loss risk; best kept short and used by people with more weight to lose |
A useful alternative to a fixed number is a percentage: aim for a deficit of roughly 15–25% below maintenance. That keeps the deficit proportional as you get lighter.
Safe floors
As a general guide, many health authorities advise not eating below about 1,500 calories a day for men or 1,200 for women without medical supervision. Below those levels it becomes genuinely hard to get enough protein, fibre, essential fats, vitamins, and minerals, and adherence usually collapses anyway. If a calculator hands you a target under those numbers, choose a slower rate of loss rather than eating less — or add activity to widen the gap from the other side.
Very-low-calorie diets (under ~800 calories) exist but are a medical intervention, done under supervision, not a DIY choice.
Protect muscle
Two things make the weight you lose come mostly from fat:
- Enough protein — around 1.6 to 2.2 g per kg of body weight per day. Protein is also the most filling macro, which helps with hunger. See macros 101.
- Resistance training — two to four sessions a week, keeping the weights genuinely challenging. This gives the body a reason to hold on to muscle. See progressive overload.
Skip both and a meaningful share of the loss will be lean tissue, which lowers your metabolic rate and makes the weight easier to regain.
Why the scale stalls
Plateaus are normal and usually not a sign the deficit has stopped working:
- Water retention masks fat loss for days or weeks — triggered by higher-carb or higher-sodium days, poor sleep, hard or novel training, travel, and (for women) the luteal phase of the menstrual cycle. Fat loss can be happening underneath a flat or rising scale.
- Adaptive changes. As you get lighter you burn a little less at rest, and NEAT (incidental movement) often drops unconsciously when you are underfed.
- Tracking drift. Portions creep up, “bites and licks” go uncounted, cooking oil is underestimated, and food labels are allowed a margin of error.
What to do: hold the target for two to three weeks and judge it on the weekly average weight, not day to day. If the average is genuinely flat, trim another 100–200 calories, add some steps, or take a planned week at maintenance (“diet break”) to recover physiologically and mentally before pushing again.
A month-by-month structure
Rather than dieting open-endedly, run it in blocks:
| Phase | Length | What to do |
|---|---|---|
| Set-up | Week 1 | Track your normal intake without changing it, to find your real starting point. Get a TDEE estimate. |
| Deficit block | 6–12 weeks | Eat at TDEE − 15–25%. Weigh daily, act on the weekly average. Adjust down 100–150 calories if two weeks are flat. |
| Diet break | 1–2 weeks | Eat at maintenance. Not a free-for-all — just remove the deficit. Restores hormones (leptin, thyroid), NEAT, and training drive, and makes the next block easier. |
| Repeat | Another deficit block, then break, until you reach your goal. | |
| Maintenance | Ongoing | Hold the new weight for at least as long as the diet took before considering another cut. This is where most regain is prevented. |
People who diet in blocks with planned breaks tend to retain more muscle, adhere better, and keep the weight off more often than people who grind a single long deficit.
Refeeds vs diet breaks
- A refeed is a single day (or two) at maintenance, usually with the extra calories coming from carbs, inside an otherwise continuous deficit. It can help training performance and morale on higher-activity days.
- A diet break is a longer stretch (1–2 weeks) fully at maintenance. This is the one with good evidence behind it for preserving metabolic rate and adherence over a long cut.
Neither is mandatory. If a straight deficit is working and you feel fine, keep going and take a break when progress or motivation stalls.
When to stop, or pause
- You have reached a healthy body composition and further loss would push you toward or below essential-fat levels.
- Sleep, mood, libido, training performance, or menstrual regularity are suffering — take a maintenance break.
- You have been dieting continuously for 3+ months — planned breaks improve long-term results and adherence.
The bottom line
Find maintenance, subtract roughly 500 calories a day (or 15–25%), and do not go below about 1,200 (women) or 1,500 (men) without supervision. Eat plenty of protein and lift weights to keep the loss coming from fat. Expect plateaus, judge progress on weekly averages, and adjust in small steps. The calorie calculator will set a target for the rate of loss you choose.