Some people do gain weight on antidepressants, but the pill doesn't make fat out of nothing. More often, small changes add up: a bigger appetite, more sleepiness, a little less moving around. Here's how much the common drugs actually differ (duloxetine, sertraline, mirtazapine and others), why "I ate nothing" is often not the whole story, and why you shouldn't stop your medication on your own.
1. The pill isn't making fat out of thin air
Weight gain during antidepressant treatment is real for some people, but a pill doesn't manufacture fat from air. Over time, gaining fat still means more energy is coming in than going out.
Things that can push weight up include a bigger appetite, changes in cravings or in how full you feel, drowsiness that means you move less, your appetite coming back as depression gets better, and in some cases water retention rather than fat.[1][2]
You don't need to start eating two dinners a night. A bit more snacking, a few sugary drinks, some late-night food and a bit less walking can make a real difference when it happens every day for months.
2. How much do the drugs actually differ?
A 2024 study looked at the records of 183,118 patients across eight US health systems and compared eight antidepressants that doctors commonly try first.[3]
At six months, compared with sertraline, the average weight differences were +0.41 kg for escitalopram, +0.37 kg for paroxetine, +0.34 kg for duloxetine and -0.22 kg for bupropion. With escitalopram, paroxetine and duloxetine, the chance of gaining at least 5% of your starting weight was also 10–15% higher.
These are averages comparing one drug with another. They are not a prediction for any one person, and the study did not include people who took no medication.
Mirtazapine is a drug with a clearer link to appetite and weight. Its US prescribing information reports that in controlled trials, 17% of patients had increased appetite and 7.5% gained at least 7% of their body weight.[1]
So yes, the choice of drug matters. But the evidence doesn't suggest that antidepressants on their own commonly double someone's weight.
3. "One boxed meal a day, and I gained over 50 kg"
Viral stories often squeeze a complicated year into one sentence. The experience may be completely genuine. What caused it is a separate question.
Does "one meal a day" include chips, sweets, sugary drinks, alcohol, milky coffee, sauces, midnight bites and other food the person doesn't think of as a "meal"? Did they move a lot less than before? Were other medicines involved? Was some of the gain water? Was there a hormone problem or another medical issue?
The fair way to read it: the weight gain may be real, but one post can't show that the antidepressant alone caused all of it.
If you gain a lot of weight very fast and can't explain it, see a doctor instead of holding a calorie trial on the internet.
4. Could a "weight-gain pill" treat starvation?
The internet-brain shortcut is obvious: if a drug can make people gain weight, why not give it to people who are severely malnourished?
Because a tablet doesn't contain lunch.
Feeling hungrier doesn't create calories, protein, fat, vitamins or the right balance of body salts. Severe malnutrition needs real food and medical care, not just a stronger urge to eat.
The World Health Organization's guideline for young children who are dangerously thin or swollen from malnutrition uses ready-to-eat, high-energy treatment food. When children are treated at home, there is a recommended stage that provides 150–185 kcal per kg of body weight per day until they meet set recovery goals.[4]
An appetite drug says "I want fuel." Nutrition treatment is the actual fuel and building material.
Pressing the gas pedal doesn't fill the tank.
5. Everyday movement burns more than you think
Your body also burns energy on everything that isn't sleeping, eating or working out.[5]
That includes standing, walking to the shop, cleaning, cooking, taking the stairs, carrying things and fidgeting.
In a small lab study of 24 adults, compared with lying flat and still, energy use went up by about 13% when standing still, 54% when fidgeting while seated, 94% when fidgeting while standing and 202% when walking at 3.2 km/h.[6]
Those numbers only apply while you are doing the activity. They don't mean "stand up and you'll automatically burn hundreds of extra calories a day."
A separate 2005 study tracked 20 people in detail and found that the people with obesity sat about two hours longer per day than the lean people. The researchers estimated that if they sat and moved like the lean group, the difference could in theory be around 350 kcal a day.[7]
Interesting? Yes. A promise for everyone? No, it was a tiny study. The useful takeaway is simpler: ordinary movement isn't zero.
6. Moving without thinking vs. snacking without thinking
| Thing you do without noticing | Likely effect |
|---|---|
| Standing, walking, cleaning, walking to the store | burn more ↑ |
| Spending much more time sitting or lying down | burn less ↓ |
| Eating chips while staring at a screen | eat more ↑ |
| Treating sugary drinks as "not food" | eat more ↑ |
| Getting watermelon juice on a white shirt without noticing | almost no calorie effect; huge crime-scene effect |
The dangerous sentence is: "I ate nothing today." Meanwhile, the bag goes crinkle crinkle.
Nothing (except the chips). Your body counts that footnote anyway.
7. Does eating in front of a screen make you eat more?
A 2026 review pooled 50 studies on eating while distracted.[8]
Overall, people didn't clearly eat more during the distracted meal itself. But they did eat more at their next meal or snack. Passive distractions like TV were also more likely to increase how much people ate right then.
So it's not "watching a screen automatically doubles your snack." A more likely pattern is: you pay less attention while eating, you remember the meal less, and you eat more later.
8. A detour: from Mori Ōgai to Koji Takamori
In the conversation this article came from, a half-remembered catchphrase about a famous Japanese novelist, Mori Ōgai, kept turning into other names, including a manga hero, before finally landing on the right person: Koji Takamori.
The official "Sukiya RADIO" page of Sukiya, a Japanese beef bowl chain, lists Koji Takamori as the show's host.[9]
This has nothing to do with weight science. It's just a perfect example of the brain mixing up similar-sounding names without asking you first.
Mori Ōgai did not secretly become a beef bowl radio host.
9. The watermelon you didn't notice
Picture eating watermelon in a white shirt. Delicious. You head home. Later you find red juice all over the shirt.
Your memory says: "ate watermelon." Anyone who saw you on the way home thought: "should we call someone?"
This is a joke, not science. But it shows a real problem: people don't remember every bite or every movement, so food diaries and activity logs based on memory miss things.
10. Change your surroundings, not your willpower
Nobody can watch every bite and every step all day. It works better to set things up so the easy choice is the better one:
- keep water or unsweetened drinks within easiest reach;
- put snacks in a small bowl instead of bringing the whole bag;
- sometimes eat without a screen;
- walk short trips when it fits naturally;
- give yourself reasons to stand up and move instead of setting extreme rules;
- if you're worried about weight gain from your medication, talk to your doctor or pharmacist instead of changing it yourself.
The NHS (the UK's public health service) specifically warns against stopping antidepressants suddenly without agreeing a plan with a doctor to cut down slowly, because stopping can cause withdrawal symptoms.[10]
11. The bottom line: we move, eat and wear watermelon without noticing
Antidepressants can play a part in weight gain, but "the drug summons fat" is the wrong picture.
Appetite, sleepiness, getting better from depression, everyday movement, snacks, distracted eating, your own body, other medicines and other health conditions can all matter.
Moving without thinking → a small ally.
Snacking without thinking → a potentially serious enemy.
Watermelon without thinking → a disaster only for the white shirt.
Managing weight often depends less on heroic willpower than on which way your automatic habits point. Walk a little. Don't bring the entire chip bag to your desk. Not glamorous, but much more realistic.
References (10)
- U.S. National Library of Medicine, DailyMed. Mirtazapine — Prescribing Information, section “Increased Appetite and Weight Gain.” Current label accessed 2026-08-28 dailymed.nlm.nih.gov
- Mayo Clinic. Antidepressants and weight gain: What causes it? Updated 2024-08-17 mayoclinic.org
- Petimar J, et al. Medication-Induced Weight Change Across Common Antidepressant Treatments: A Target Trial Emulation Study. Annals of Internal Medicine. 2024;177(8):993-1003. PMID: 38950403 pubmed.ncbi.nlm.nih.gov
- World Health Organization. WHO guideline on the prevention and management of wasting and nutritional oedema (acute malnutrition) in infants and children under 5 years. 2023 who.int
- Levine JA. Nonexercise activity thermogenesis (NEAT): environment and biology. Am J Physiol Endocrinol Metab. 2004;286(5):E675-E685. PMID: 15102614 pubmed.ncbi.nlm.nih.gov
- Levine JA, Schleusner SJ, Jensen MD. Energy expenditure of nonexercise activity. Am J Clin Nutr. 2000;72(6):1451-1454. PMID: 11101470 pubmed.ncbi.nlm.nih.gov
- Levine JA, et al. Interindividual variation in posture allocation: possible role in human obesity. Science. 2005;307(5709):584-586. PMID: 15681386 pubmed.ncbi.nlm.nih.gov
- Gough T, et al. Eating while distracted: a systematic review and meta-analysis of the effect of distraction on concurrent and later energy intake in adults. Am J Clin Nutr. 2026;123(6):101315. PMID: 41999952 pubmed.ncbi.nlm.nih.gov
- Sukiya (すき家). すき家RADIO — Profil des Moderators: Koji Takamori (高森浩二) news.sukiya.jp
- NHS. Antidepressants — stopping or coming off antidepressants. Page last reviewed 2025-06-12 nhs.uk
