Calories per day: how many should you eat to lose weight without going too low?
Key takeaways
- The Thai nutrition flag uses about 1,600 kcal for working women and 2,000 for men; your TDEE decides
- To lose about 0.5 kg a week, eat about 550 kcal a day less than your TDEE
- If weight stalls for 2–3 weeks, cut 100–200 kcal, staying above 1,200 for women or 1,500 for men
The calories per day you need depend on how much energy your body uses in a day, your TDEE. Thailand's Department of Health nutrition flag uses about 1,600 kcal for working-age women and 2,000 kcal for working-age men. To lose weight, eat about 550 kcal a day less than your TDEE to lose about 0.5 kg a week, but women should not go below 1,200 kcal and men not below 1,500 kcal a day.
In this guide (7 sections)
- How many calories per day should you eat?
- What are BMR and TDEE, and how are they different?
- How different are calories per day for women and men?
- How many calories should you eat a day to lose weight?
- Why shouldn't you eat less than 1,200 or 1,500 calories per day?
- You know your number. How do you plan meals around it?
- Don't want to count calories at every meal?
How many calories per day should you eat?
As a broad guide, the nutrition flag (thong pho-cha-na-kan) from Thailand's Department of Health sets 3 energy levels for Thai people. It is a good starting point.
| Energy per day | Suits |
|---|---|
| 1,600 kcal | Children aged 6–13, working-age women aged 25–60, and people aged 60 and over |
| 2,000 kcal | Teenagers and young adults aged 14–25, and working-age men aged 25–60 |
| 2,400 kcal | Women and men who use a lot of energy, such as manual workers, farmers and athletes |
These are averages for large groups, and people use different amounts of energy. A small person who sits all day may use less than 1,600 kcal, while a large person who trains often may use more than 2,400. To get your own number, you need to know your BMR and TDEE.
What are BMR and TDEE, and how are they different?
BMR is the energy your body uses at complete rest, to keep your heart beating, your lungs breathing and your organs working. TDEE is the energy you really use in a whole day: your BMR, plus digesting food, plus every kind of movement. So TDEE is always higher than BMR. Digesting food alone uses about 5–15% of daily energy, according to a paper by Westerterp (2004).
CleanFit's TDEE calculator (the page is in Thai) uses the Mifflin-St Jeor equation, published in 1990, to find your BMR, then multiplies it by an activity factor.
- Men: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) + 5
- Women: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) − 161
- TDEE = BMR × activity factor
| Activity level | Factor |
|---|---|
| Desk job, little or no exercise | 1.2 |
| Light exercise 1–3 days a week | 1.375 |
| Moderate exercise 3–5 days a week | 1.55 |
| Hard exercise 6–7 days a week | 1.725 |
| Very hard exercise or physical work | 1.9 |
How different are calories per day for women and men?
Men usually have a higher BMR, because the equation adds more for men and men are often larger. Here are 4 examples, worked out with the equation above.
| Example | Activity | BMR | TDEE |
|---|---|---|---|
| Woman, 30, 160 cm, 55 kg | Desk job (1.2) | 1,239 kcal | about 1,487 kcal |
| Woman, 30, 160 cm, 70 kg | Light exercise (1.375) | 1,389 kcal | about 1,910 kcal |
| Man, 30, 170 cm, 70 kg | Desk job (1.2) | about 1,618 kcal | about 1,941 kcal |
| Man, 35, 172 cm, 80 kg | Light exercise (1.375) | 1,705 kcal | about 2,344 kcal |
Notice that the smaller woman with a desk job uses less than 1,600 kcal, while the heavier woman who exercises a little uses almost 2,000 kcal. The equation gives an estimate that can be about 10% off. Use it as a starting point and check it against your real weight.
How many calories should you eat a day to lose weight?
Eat about 550 kcal a day less than your TDEE to lose about 0.5 kg a week. This comes from the rule that 1 kg of body fat is roughly 7,700 kcal, converted from Wishnofsky's (1958) estimate of 3,500 kcal per pound of fat, and it is the same figure our TDEE calculator uses. In real life, weight loss usually slows over time, so work out your numbers again every so often.
- Safe plan: about 0.5 kg a week, and no more than 0.75% of your body weight
- Fastest plan we still suggest: no more than 1 kg or 1% of your body weight a week
- Daily minimum: 1,200 kcal for women and 1,500 kcal for men, unless a doctor is supervising you
| Example (from the table above) | TDEE | Eat per day | Weekly loss (approx.) |
|---|---|---|---|
| Woman, 55 kg, desk job | 1,487 kcal | 1,200 kcal (minimum) | 0.25 kg |
| Woman, 70 kg, light exercise | 1,910 kcal | 1,360 kcal | 0.5 kg |
| Man, 70 kg, desk job | 1,941 kcal | 1,500 kcal (minimum) | 0.4 kg |
| Man, 80 kg, light exercise | 2,344 kcal | 1,794 kcal | 0.5 kg |
People whose TDEE is already low, such as smaller women with desk jobs, will lose weight more slowly. Rather than eating even less, it works better to move more, for example by walking more every day. Your TDEE goes up, and you have more room to eat.
Why shouldn't you eat less than 1,200 or 1,500 calories per day?
Eating too little makes it hard to get enough nutrients, leaves you too hungry to keep going, and makes it easier to lose muscle. Very strict diets rarely last long. That is why our calculator does not go below 1,200 kcal for women or 1,500 kcal for men.
- As you lose weight, your TDEE drops too. Work out your numbers again every 4–6 weeks, or when your weight changes by more than 3–5 kg
- Weigh yourself regularly for 2–3 weeks. If your weight does not move, lower your calories by 100–200 kcal at a time, but not below the minimum
- Eat enough protein. When losing weight, use 1.6 g per kg of target weight. Details are in protein for weight loss
If you are pregnant or breastfeeding, have diabetes or kidney disease, or take regular medication, talk to a doctor or dietitian before cutting calories. For the bigger picture on weight loss you can keep up, read how to lose weight.
You know your number. How do you plan meals around it?
First, enter your weight, height, age and activity in our free TDEE calculator (in Thai). You get your calories, protein and a plan in 4-week phases. Then split the total into meals. For example, a 1,400 kcal target could be 350 for breakfast, 450 for lunch, 400 for dinner and a 200 kcal snack.
The hard part is knowing how many calories each meal has. Every CleanFit dish shows its calories and protein, at 70–330 kcal per meal, without rice. For example, Ka Pow Kai has 180 kcal and 33 g of protein. Fill the rest of that meal's budget with rice and vegetables. Every dish is made with no cooking oil, no MSG, no added sugar and no preservatives, is Thai FDA approved, and has lab-tested nutrition.
For full-day examples, see 1200 calorie menu and 7-day weight loss menu. If you are just starting, the first-week steps are in diet control for beginners.
Don't want to count calories at every meal?
The easiest way is to keep food with known numbers close at hand. Pick a main dish that fits the meal's calories and adjust only the rice, so you do not have to guess oil or sauces. Order a pack and choose every dish yourself. Meals keep in the freezer for up to 120 days.
Frequently asked questions
How many calories per day should a woman eat?
The Department of Health nutrition flag uses about 1,600 kcal for working-age women, but your real number depends on your size and activity. A 30-year-old woman who is 160 cm, 55 kg and has a desk job has a TDEE of about 1,490 kcal. When losing weight, do not go below 1,200 kcal.
How many calories per day should a man eat?
The nutrition flag uses about 2,000 kcal for working-age men. Larger men or men who exercise often use more. When losing weight, do not go below 1,500 kcal a day.
Can I eat 1,000 calories a day?
Not without a doctor's supervision. It is below the minimum for both women and men, makes it hard to get enough nutrients, and is hard to keep up. Try moving more instead of cutting food further.
Do I need to eat more when I exercise?
If the activity level you chose already includes your exercise, do not add more, or you will count it twice. On a day with much more exercise than usual, you can add a little.
I eat to my calorie target but my weight is not going down. What should I do?
The equation can be about 10% off. Weigh yourself regularly for 2–3 weeks, then lower your calories by 100–200 kcal at a time without going below the minimum. Also check that you are counting cooking oil, drinks and snacks.
Written by the CleanFit teamCalories and protein for each CleanFit dish come from our ordering system. Figures for other foods cite the sources named in the guide.
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