Key takeaways
- Body size sets your baseline: a 155 cm (5′1″), 52 kg (115 lb) woman with a desk job burns only about 1,400 kcal a day.
- Everyday movement is the part of TDEE that varies most, and the easiest to raise.
- After a long diet, TDEE falls because you weigh less and often move less, plus a modest adaptation.
- Feeling cold, tired and sluggish along with a low TDEE is a reason to see a doctor and check your thyroid.
On this page
First: is your TDEE really low?
A number feels low when you compare it with someone else’s, or with the 2,000 kcal on food labels. But that 2,000 is a reference value for labels, not a target for every adult. Many people, especially smaller women, need much less.
A 30-year-old woman who is 155 cm (5′1″) and 52 kg (115 lb), with a desk job and little exercise:
BMR = 10 × 52 + 6.25 × 155 − 5 × 30 − 161 = 1,178 kcal TDEE = 1,178 × 1.2 = 1,413 kcal a day
If she wants to lose weight, a 20% deficit would put her at about 1,130 kcal, below the 1,200 kcal a day usually recommended as a minimum without supervision. That is frustrating, but it is arithmetic, not a fault in her body. The answer is a smaller deficit, more movement, or both, rather than eating even less.
So the first question is whether your number fits your size and lifestyle. Compare it with the TDEE calculator, and if you measured it from your own log, read the section on measured numbers below.
Seven reasons a TDEE can be low
1. You are smaller or shorter
Every kilo of body weight adds about 10 kcal to resting metabolism, and every centimetre of height about 6. A petite body simply costs less to run and less to move. This is the most common reason, and the least worrying.
2. Your days involve little movement
Car to desk to sofa can mean fewer than 3,000 steps a day. Everyday movement outside exercise, called NEAT, is the most variable part of TDEE. In one well-known overfeeding study, the people who gained least fat were the ones whose everyday movement rose most. The reverse is true too: a very still routine keeps TDEE low even if you go to the gym.
3. You carry less muscle
Muscle burns about three times more energy at rest than fat per kilo, and it lets you train harder. People who have never done strength training, or who have lost muscle with age, illness or crash diets, tend to have a lower TDEE for their size.
4. You have been dieting for a while
Weight loss lowers TDEE in three ways. You weigh less, so you burn less. Many people move less without noticing when food is short. And the body becomes a little more efficient, an effect called adaptive thermogenesis. Research summarised by Rosenbaum and Leibel found that people keeping off 10% or more of their body weight burned about 20 to 25% less energy a day than before, roughly 10 to 15% less than their smaller size alone would predict.
5. Your age
Less than you might think. A 2021 study of over 6,000 people found that energy use, adjusted for body size and composition, stays fairly stable from about 20 to 60 and declines after that. In the Mifflin-St Jeor equation, each year takes off 5 kcal. Most of what people blame on age is really less muscle and less movement.
6. Your log or your settings
If your “low TDEE” was measured from your own food log, the most likely explanation is food that didn’t get recorded. In one classic study, people who said they couldn’t lose weight on low intakes were eating far more than they logged and moving less than they reported. Cooking oil, drinks, sauces and weekends are the usual gaps. A window that included water loss or gain can also skew the answer.
7. A health condition or medicine
An underactive thyroid (hypothyroidism) lowers metabolic rate, and treatment usually brings it back towards normal. Some medicines, such as certain antidepressants, antipsychotics, steroids and diabetes treatments, can affect appetite, weight or energy use. If you have symptoms such as tiredness, feeling cold, constipation, dry skin or unexplained weight gain, ask your doctor for a check-up. Don’t stop any medicine without talking to them.
If your measured TDEE is lower than the calculator
When people track food and weight and calculate their real TDEE, it sometimes comes out several hundred calories below the calculator. Before deciding your metabolism is slow, check these in order:
- Was the log complete? Weigh your food for one week, including oils and drinks, and compare it with your usual logging.
- Was the window long enough? Under two weeks, water swings dominate. Use three or four weeks.
- Did it start on the first week of a diet? Early water loss makes weight drop fast and can make TDEE look higher; a window that starts after a big carb meal can do the opposite.
- Did your activity drop? Compare your step count with the start of the period.
If all four check out and the gap stays large, it’s reasonable to see your doctor.
What actually helps
| Change | Roughly worth | Notes |
|---|---|---|
| 3,000 more steps a day | 50 to 120 kcal a day | More for heavier people. The easiest and most reliable lever |
| Strength training 2 to 3 times a week | Tens of kcal a day at first | Builds muscle over months, raises training capacity and protects muscle in a deficit |
| Standing and moving more at work | Small to moderate | Standing alone adds little; walking breaks add more |
| Higher protein intake | A little, through digestion | Mainly helps fullness and muscle |
| Diet breaks at maintenance | Indirect | Helps restore energy, training and daily movement |
| Better sleep | Indirect | Tired people move less and eat more |
Our guide on how to increase your TDEE goes through each of these with more numbers, and the steps calculator shows what extra walking is worth for your body.
Eating very little can push TDEE lower
When TDEE seems low, the natural reaction is to eat even less. That often backfires. A very large deficit makes you tired, so you move less without meaning to. It costs muscle, which lowers resting burn. It makes training sessions weaker, so they burn less. And it increases hunger, which makes the diet harder to keep. The result can be a lower TDEE and the same weight.
The way out is usually the opposite of what feels right: eat closer to maintenance for a few weeks, keep protein high, lift weights and walk more. Many people find their TDEE, and their energy, comes back up, and that the next diet phase works better.
Losing weight with a low TDEE
A low TDEE makes weight loss slower, not impossible. Some practical rules:
- Use a smaller deficit of 10 to 15% and accept a slower pace, such as 0.25 kg (½ lb) a week. Slow loss that you can keep beats fast loss you can’t.
- Raise your TDEE rather than cutting food further. An extra 3,000 to 5,000 steps a day can give you 100 to 200 kcal of room.
- Prioritise protein and vegetables, which keep you full on fewer calories.
- Don’t go below about 1,200 kcal a day without medical supervision.
- Take diet breaks at maintenance every couple of months if the diet is long.
Questions about a low TDEE
Is a TDEE of 1,400 normal?
For a small, mostly sedentary woman, yes. A 30-year-old who is 155 cm (5′1″) and 52 kg (115 lb) with a desk job has an estimated TDEE of about 1,400 kcal. For a larger or more active person it would be unusually low and worth checking.
Can I increase my TDEE?
Yes. The biggest, most reliable change is more daily movement, especially walking. Strength training builds muscle over time and lets you train harder. Cold water, spicy food and supplements make only tiny differences.
Is the drop in TDEE after dieting permanent?
Most of it is simply because you weigh less, and that part stays as long as your weight does. The extra adaptation is usually modest and tends to ease with time at maintenance, more daily movement and enough food. Extreme cases, like contestants on very aggressive TV weight-loss shows, are not typical.
Why is my TDEE lower than my friend’s?
Usually because of differences in size, muscle and daily movement. Two people who eat the same and go to the same gym can still differ by several hundred calories a day if one walks much more at work.
Should I eat under 1,200 calories if my TDEE is low?
Not without medical supervision. Use a smaller deficit and raise your TDEE with more movement instead. If you feel you can’t lose weight above 1,200 kcal, talk to a doctor or registered dietitian.
Could a medical problem be causing my low TDEE?
It can. An underactive thyroid is the most common one. If a low TDEE comes with tiredness, feeling cold or other symptoms, see your doctor for a simple blood test.
Sources
- Mifflin MD, St Jeor ST, Hill LA, et al. A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr. 1990;51(2):241-247. doi.org/10.1093/ajcn/51.2.241
- Levine JA, Eberhardt NL, Jensen MD. Role of nonexercise activity thermogenesis in resistance to fat gain in humans. Science. 1999;283(5399):212-214. doi.org/10.1126/science.283.5399.212
- Pontzer H, Yamada Y, Sagayama H, et al. Daily energy expenditure through the human life course. Science. 2021;373(6556):808-812. doi.org/10.1126/science.abe5017
- Rosenbaum M, Leibel RL. Adaptive thermogenesis in humans. Int J Obes (Lond). 2010;34(Suppl 1):S47-S55. doi.org/10.1038/ijo.2010.184
- Fothergill E, Guo J, Howard L, et al. Persistent metabolic adaptation 6 years after “The Biggest Loser” competition. Obesity (Silver Spring). 2016;24(8):1612-1619. doi.org/10.1002/oby.21538
- Lichtman SW, Pisarska K, Berman ER, et al. Discrepancy between self-reported and actual caloric intake and exercise in obese subjects. N Engl J Med. 1992;327(27):1893-1898. doi.org/10.1056/NEJM199212313272701
- American Thyroid Association. Thyroid and weight. Patient information. www.thyroid.org/thyroid-and-weight/