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体に悪い

B1 noun #4,500 most common 11 min read

体に悪い

karada ni warui Top 4,500

Practice it Examples Notes & Tips 体に悪い in 30 Seconds

Explanation 体に悪い in your Level:

At the A1 level, you should learn '体に悪い' (Karada ni warui) as a fixed phrase that means 'bad for the body' or simply 'unhealthy.' In Japanese, '体' (karada) means body, and '悪い' (warui) means bad. The small word 'に' (ni) acts like 'for.' You can use this phrase to talk about things like candy, soda, or not sleeping. It is a very useful way to express that something is not good for you. At this level, don't worry too much about the complex grammar; just remember the pattern: [Something] は体に悪いです. For example, 'Pizza は体に悪いです' (Pizza is bad for the body). This is a polite way to say something is unhealthy. It is one of the first phrases Japanese children learn because parents use it all the time! You will see the kanji for 'body' (体) and 'bad' (悪) very often in Japan, so learning this phrase helps you recognize them. When you see a sign with '体に悪い' in a grocery store or on TV, you will know it is talking about health risks. Try to practice it by pointing at things like cigarettes or greasy food and saying '体に悪い' to yourself. It is a very simple but powerful way to start talking about your health in Japanese.

At the A2 level, you can start using '体に悪い' (Karada ni warui) to build slightly more complex sentences. You should understand that '悪い' is an i-adjective, which means it changes its ending depending on the tense. For example, if you want to say something *was* bad, you say '体に悪かったです' (Karada ni warukatta desu). If you want to say something is *not* bad, you say '体に悪くないです' (Karada ni warukunai desu). You can also use it to describe a noun directly, like '体に悪い食べ物' (Karada ni warui tabemono - unhealthy food). This is a great way to expand your vocabulary for shopping or eating out. You might also encounter the opposite phrase, '体に良い' (Karada ni yoi - good for the body). Comparing these two will help you understand how particles work. Remember that 'に' is essential here. If you accidentally say '体が悪い' (Karada ga warui), people might think you are saying you are currently sick or have a physical problem. At A2, focus on using the phrase to give simple advice to friends, like '夜更かしは体に悪いですよ' (Staying up late is bad for your health). This shows you can use the phrase in a social, helpful way.

At the B1 level, you should be comfortable using '体に悪い' (Karada ni warui) in a variety of grammatical structures and social contexts. You should understand the nuance between this phrase and more formal terms like '不健康' (hukenkou - unhealthy) or '有害' (yuugai - harmful). While '体に悪い' is perfect for daily conversation, you'll start to notice it in health-related news articles and 'Kenko Bangumi' (health variety shows) on Japanese TV. You should be able to use nominalized verbs as subjects, such as '毎日カップラーメンを食べるのは体に悪い' (Eating cup ramen every day is bad for the body). This level also involves understanding the cultural context of health in Japan. For instance, you might hear people say '体に悪い' in relation to the 'tsuyu' (rainy season) or high humidity, reflecting the belief that the environment directly impacts physical balance. You can also use the te-form to connect reasons: 'この仕事はストレスが多くて、体に悪い' (This job is stressful and bad for my health). At B1, you are expected to not only state that something is bad but also explain *why* or *how* it affects you using this phrase. It’s about moving from simple labels to discussing lifestyle habits and their consequences.

At the B2 level, you should be able to use '体に悪い' (Karada ni warui) and its derivatives to discuss more abstract or systemic health issues. You might use it when talking about environmental pollution, the impact of 'black companies' (exploitative workplaces), or the sociological aspects of the modern diet. You should be able to distinguish between '体に悪い' and '体に障る' (karada ni sawaru), the latter being used when something specifically aggravates a pre-existing condition or interferes with recovery. You can also use more advanced adverbs to qualify the phrase, such as '著しく体に悪い' (ichijirushiku... - significantly bad for the body) or '長期的に見て体に悪い' (choukiteki ni mite... - bad for the body in the long term). At this level, you should be able to engage in a debate about health trends, using the phrase to argue against certain habits while acknowledging the 'guilty pleasure' aspect (e.g., '体に悪いと知りつつも、やめられない' - Even though I know it's bad for me, I can't stop). You should also be familiar with the use of '体に毒' (karada ni doku - poison for the body) as a more emphatic, often colloquial alternative. Your ability to use the phrase should now reflect a deeper understanding of Japanese sentence flow and the subtle social cues of giving health advice without being overbearing.

At the C1 level, your use of '体に悪い' (Karada ni warui) should be nuanced and contextually perfect. You should be able to analyze the phrase's role in Japanese 'omoiyari' (consideration) culture, where expressing concern for someone's health is a key social lubricant. You will understand how the phrase is used in literature or high-level journalism to critique modern society's detachment from physical well-being. You should be able to seamlessly switch between '体に悪い' and more academic terms like '健康被害を及ぼす' (kenko higai o oyobosu - to cause health damage) or '生理学的に悪影響を与える' (seirigakuteki ni... - to have a negative physiological effect) depending on the audience. You can discuss the etymology and the holistic view of 'body' in Japanese culture, where the distinction between mental and physical health is often more fluid than in Western concepts. Your mastery should include understanding when *not* to use the phrase—for instance, avoiding it in situations where it might sound patronizing or when a more specific medical term is required. You can use it in complex conditional sentences, such as 'これほどまでに体に悪い習慣が蔓延している背景には、現代社会の構造的問題がある' (Behind the spread of such unhealthy habits lies the structural problems of modern society).

At the C2 level, you possess a native-like grasp of '体に悪い' (Karada ni warui), including its metaphorical and idiomatic potential. You can use the phrase with a high degree of irony, sarcasm, or poetic flair. You understand its place within the broader tapestry of Japanese health philosophy, including 'Ishoku Dogen' and 'Yakuzen.' You can critique how the phrase is used in marketing to manipulate consumer fear or how it features in political discourse regarding public health policies. Your understanding extends to regional variations or archaic forms that might appear in classical literature or specific dialects. You can write sophisticated essays or give presentations on public health, using '体に悪い' as a foundational concept while layering it with technical, sociological, and philosophical terminology. You can detect the subtle difference in tone when a doctor uses the phrase versus a grandmother, and you can replicate those tones perfectly in your own speech. At this level, the phrase is no longer just a vocabulary item; it is a tool for expressing complex observations about the human condition, the environment, and the intersection of biology and culture. You can effortlessly navigate the fine line between casual concern and professional assessment, making you a highly effective communicator in any Japanese-speaking environment.

Practice it Examples Notes & Tips

体に悪い in 30 Seconds

Used to describe anything that negatively impacts physical health, from junk food to lack of sleep.
A very common everyday phrase used by parents, doctors, and friends to show concern.
Grammatically an i-adjective phrase; can end sentences or modify nouns directly.
Culturally reflects the Japanese emphasis on 'kenko' (health) and maintaining physical balance.

The Japanese phrase 体に悪い (Karada ni warui) is a quintessential expression used to describe anything that has a negative impact on one's physical health or well-being. At its most basic level, it translates to 'bad for the body' or 'unhealthy.' However, its usage in Japanese society carries a weight of social responsibility and personal concern that often goes beyond a simple dietary observation. In Japan, maintaining 'kenko' (health) is seen as a fundamental duty to oneself and one's family, and therefore, labeling something as karada ni warui is a common way to offer advice, express self-reproach, or criticize modern lifestyle habits.

Literal Breakdown: The phrase consists of '体' (karada), meaning body; the particle 'に' (ni), indicating the target or direction of the effect; and '悪い' (warui), the i-adjective for bad or evil. Together, they form a descriptive predicate.
Broad Application: While often associated with 'junk food' or 'smoking,' it is equally applied to lack of sleep, excessive stress, poor posture, or even negative environmental factors like pollution or extreme cold.
Social Context: Using this phrase is frequently a sign of 'omoiyari' (consideration). A mother might say it to a child eating sweets, or a colleague might say it to another who is working too many overtime hours.

夜更かしは体に悪いですよ。 (Staying up late is bad for your health.)

— A common warning given to students or night owls.

In a cultural sense, Japan has a deep-rooted concept of 'Ishoku Dogen' (medicine and food have the same source). This means that every meal is viewed as a potential medicine or a potential toxin. When a Japanese person identifies a food as 体に悪い, they are not just making a nutritional statement; they are identifying a disruption to the natural balance of the body. This is why you will hear the phrase used so frequently in daily conversations about lunch choices, work-life balance, and even the weather. For example, sudden temperature changes are often described as karada ni warui because they strain the body's ability to regulate itself.

インスタントラーメンばかり食べるのは体に悪いと分かっています。 (I know that eating nothing but instant ramen is bad for my body.)

Furthermore, the phrase can be used to describe emotional or mental states that manifest physically. Working in a toxic environment (black kigyo) is often described as karada ni warui because the stress eventually leads to physical illness. In this way, the 'body' in the phrase encompasses the entire physical and mental vessel of the person. It is a holistic term that warns against the erosion of vitality. Whether it is the grease in a burger or the pressure of an exam, if it wears you down, it is 体に悪い.

Grammatically, 体に悪い (Karada ni warui) functions as an adjectival phrase. Because it ends with the i-adjective '悪い', it follows all the standard rules for i-adjective conjugation. You can use it to end a sentence, to modify a noun, or in various conditional and connective forms. Understanding how to link it to the 'cause' of the health risk is key to sounding natural.

Sentence Ending (Predicative): The most common form is [Subject] + は + 体に悪い. For example: 'タバコは体に悪い' (Smoking is bad for the body). In polite speech, add 'です' (desu).
Noun Modification (Attributive): You can place the whole phrase directly before a noun: [体に悪い] + [Noun]. Example: '体に悪い習慣' (Unhealthy habits) or '体に悪い食べ物' (Unhealthy food).
Past Tense and Negation: Past: 体に悪かった (It was bad for the body). Negative: 体に悪くない (It is not bad for the body). Past Negative: 体に悪くなかった (It was not bad for the body).

そんなに体に悪いもの、食べないでください。 (Please don't eat such an unhealthy thing.)

When you want to emphasize *how* bad something is, you can add adverbs like 'すごく' (sugoku - very), '絶対' (zettai - definitely), or 'あまり' (amari - not very, in negative sentences). For example, 'あまり体に悪くないお菓子' (Sweets that aren't very bad for you). The particle 'に' is crucial; it acts as the bridge between the body and the 'badness,' indicating the target of the negative effect. If you omit 'に', the sentence becomes '体が悪い' which means 'My body is bad' (often meaning 'I am in poor health' or 'I have a physical disability'), which is a very different meaning.

In more complex sentences, you can use the 'te-form' (体に悪くて) to list multiple qualities. 'このお菓子は体に悪くて、値段も高い' (These sweets are bad for the body and expensive too). You can also use nominalizers like 'の' or 'こと' to make the act of doing something bad for the body the subject: '夜中にラーメンを食べるのは体に悪い' (Eating ramen in the middle of the night is bad for the body). This pattern is extremely common in health advice columns and parental scolding.

ストレスは体に悪いと分かっていても、なかなか避けられません。 (Even though I know stress is bad for my body, I can't quite avoid it.)

Finally, consider the register. In formal medical settings, a doctor might use the term '健康を害する' (kenko o gaisuru - to harm health), but in the consultation room, they will still frequently use karada ni warui to ensure the patient understands the immediate impact of their habits. It is a bridge between technical medical jargon and everyday concern.

You will encounter 体に悪い (Karada ni warui) in a vast array of social settings in Japan, ranging from the domestic to the commercial. It is one of those 'high-frequency' phrases that reflects the Japanese preoccupation with longevity and health maintenance. Whether you are watching a variety show on TV or sitting in a family restaurant, the concept of things being 'bad for the body' is never far away.

In the Kitchen / Dining Table: This is the primary battleground for the phrase. Parents use it to discourage children from eating too much candy or drinking soda. Friends might use it jokingly when ordering a second round of deep-fried 'karaage' at an izakaya.
In the Workplace: Japanese work culture is known for long hours. You will often hear colleagues say, 'そんなに遅くまで働くと体に悪いよ' (Working that late is bad for your body). It is a way of showing 'enryo' (restraint) and care for one's peers.
In Advertising and Media: Health-themed variety shows (often called 'Kenko Bangumi') are a staple of Japanese television. Experts will point to various foods or habits and label them as 'karada ni warui' to grab the audience's attention.

「最近、全然寝てないんだ」「それは体に悪いから、今日は早く帰りなよ」 ( 'I haven't slept at all lately.' 'That's bad for you, so go home early today.' )

Another interesting place you hear this word is in the context of seasonal changes. In Japan, the transition between seasons (especially the 'tsuyu' rainy season or the humid summer) is considered physically taxing. Older generations especially will warn that letting your stomach get cold or not eating enough 'unagi' (eel) during the hottest days is karada ni warui. This connects the phrase to traditional folk wisdom and 'yakuzen' (medicinal cooking) concepts.

Finally, the phrase appears frequently in self-deprecating humor. When someone indulges in a 'guilty pleasure'—like a massive bowl of fatty ramen after a night of drinking—they might say, '体に悪いものほど美味しいよね' (The things that are bad for the body are the most delicious, aren't they?). This shows that while the Japanese are health-conscious, they are also very aware of the temptations of the 'unhealthy.' It is a phrase that encapsulates the constant struggle between discipline and indulgence.

この部屋の空気、体に悪い感じがする。換気しよう。 (The air in this room feels bad for the body. Let's ventilate.)

While 体に悪い (Karada ni warui) seems straightforward, English speakers often stumble on the nuances of particles and the distinction between 'being unhealthy' and 'doing something unhealthy.' Avoiding these pitfalls will make your Japanese sound much more natural and precise.

Mistake 1: Confusing '体に悪い' with '体が悪い': This is the most common error. '体に悪い' (Ni) means 'bad FOR the body.' '体が悪い' (Ga) means 'The body IS bad.' If you say '私は体が悪い,' people will think you have a chronic illness or a disability. If you mean you have bad habits, you should say '私の生活は体に悪い' (My lifestyle is bad for my body).
Mistake 2: Using '不健康' (Hukenkou) in Casual Speech: '不健康' is a noun/na-adjective that means 'unhealthy' in a more clinical or abstract sense. While correct, it sounds stiff. In a conversation about greasy food, '体に悪い' is much more natural than '不健康な食べ物'.
Mistake 3: Forgetting the 'i' in 'Warui': Because it's an i-adjective, you must conjugate it correctly. Learners often say '体に悪いだ' (Warui da), which is incorrect. It should be '体に悪い' or '体に悪いです'.

❌ 昨日の食事は体に悪いでした。
✅ 昨日の食事は体に悪かったです。 (Yesterday's meal was bad for my body.)

Another subtle mistake is using it for things that are 'dangerous' but not necessarily 'unhealthy.' For example, if you are walking on a high ledge, you wouldn't say it's karada ni warui; you would say '危ない' (abunai - dangerous). Karada ni warui is specifically for things that erode health over time or through ingestion/exposure, like toxins, radiation, or bad habits. It’s about the physiological impact, not immediate physical trauma.

Lastly, learners sometimes over-rely on the phrase for moral judgments. While 'warui' can mean 'evil' or 'bad' in a moral sense, karada ni warui is strictly biological. If you want to say someone is a 'bad person,' you just say '悪い人' (warui hito). Adding '体に' makes it specifically about health. Conversely, don't use it for broken objects. A broken car isn't '体に悪い'; it's '故障している' (koshou shiteiru).

❌ このスマホは体に悪い。
✅ このスマホは壊れている。 (This phone is broken.)
*Unless you mean the radiation from the phone is unhealthy!

While 体に悪い (Karada ni warui) is the go-to phrase for most situations, Japanese offers several alternatives that can add precision, formality, or a different flavor to your speech. Depending on whether you are talking to a friend, a doctor, or writing a report, you might choose a different term.

不健康 (Hukenkou): Meaning 'unhealthy.' This is a na-adjective/noun. It is more abstract and formal. You use it to describe a lifestyle or a person's general state.
Example: 不健康な生活 (An unhealthy life).
有害 (Yuugai): Meaning 'harmful' or 'toxic.' This is a much stronger word. It is used for things like chemicals, illegal substances, or 'harmful content' on the internet.
Example: 体に有害な物質 (Substances harmful to the body).
毒 (Doku): Meaning 'poison.' In casual Japanese, people often say '体に毒' (karada ni doku) to mean 'poisonous to the body' or 'extremely unhealthy.' It's a hyperbole often used for delicious but fatty foods.

「このケーキ、砂糖がすごそうだね」「体に毒だけど、食べちゃおう！」 ( 'This cake looks like it has a ton of sugar.' 'It's poison for the body, but let's eat it anyway!' )

For the opposite meaning, the most common phrase is 体に良い (Karada ni yoi). You can also use '健康にいい' (Kenko ni ii). In more formal contexts, you might hear '養生になる' (Youjou ni naru), which means 'to be good for one's health/recuperation,' or '滋養がある' (Jiyou ga aru), meaning 'nutritious' or 'nourishing.'

Another useful phrase is '体に障る' (Karada ni sawaru). This specifically means something 'interferes' with or 'affects' your health negatively, often used when someone is already weak or recovering. For instance, '無理をすると体に障りますよ' (If you overdo it, it will affect your health). It carries a nuance of 'irritating' or 'aggravating' a physical condition, rather than just being generally unhealthy like karada ni warui.

酒は百薬の長といえど、飲みすぎれば毒になる。 (They say sake is the best of all medicines, but if you drink too much, it becomes poison.)

In summary, while 体に悪い is the most versatile and common, using doku adds a bit of flavor, yuugai adds seriousness, and hukenkou adds an air of clinical assessment. Choosing the right one depends on how much 'badness' you want to convey.

How Formal Is It?

Fun Fact

The kanji for 'body' (体) is a simplified version of '體.' The left side '亻' is the 'person' radical, and the right side '本' means 'root' or 'origin,' suggesting the body is the root of a person.

Pronunciation Guide

UK kɑːrɑːdɑː ni wɑːruːiː

US kɑːrɑːdɑː ni wɑːruːiː

Japanese is a pitch-accent language. In 'karada,' the pitch is low-high-high. In 'warui,' it is low-high-low.

Rhymes With

Marui (Round) Karui (Light) Surui (Sly) Yurui (Loose) Furui (Old) Akarui (Bright) Nurui (Lukewarm) Muzukashii (Difficult - only the final 'i')

Common Errors

Stressing the 'ni' too much.
Pronouncing 'warui' like 'wa-roo-ee' with a heavy 'w'.
Failing to pronounce the final 'i' in 'warui' clearly.
Using an English 'r' sound instead of the Japanese tap.
Stopping after 'karada' and losing the flow of the phrase.

Difficulty Rating

Reading 2/5

The kanji for 'body' and 'bad' are basic (JLPT N4/N5 level).

Writing 3/5

The kanji '悪い' has several strokes, but is very common.

Speaking 1/5

The phrase is phonetically simple and easy to remember.

Listening 1/5

It is a very distinct and frequently used phrase in audio.

What to Learn Next

Prerequisites

体 (Body) 悪い (Bad) に (Particle) 食べ物 (Food) 良い (Good)

Learn Next

不健康 (Unhealthy) 健康 (Health) 影響 (Influence) 習慣 (Habit) 害する (To harm)

Advanced

生活習慣病 (Lifestyle diseases) 滋養強壮 (Nutritional fortification) 摂生 (Hygiene/care of health) 有害物質 (Harmful substances)

Grammar to Know

I-adjective conjugation

悪い (Present), 悪かった (Past), 悪くない (Negative)

Particle 'ni' for target/effect

体に悪い (Bad for the body), 目に良い (Good for the eyes)

Nominalization with 'no'

食べるのは体に悪い (Eating is bad for the body)

Adverbial form of adjectives

体に悪く影響する (To affect the body badly)

Giving advice with 'hou ga ii'

体に悪いから、やめたほうがいい。

Examples by Level

タバコは体に悪いです。

Smoking is bad for the body.

Simple [Noun] は [Phrase] です structure.

お菓子は体に悪いですか？

Are sweets bad for the body?

Adding 'ka' to make a question.

コーラは体に悪いです。

Cola is bad for the body.

Using katakana nouns with the phrase.

体に悪い食べ物です。

It is an unhealthy food.

Attributive use: modifying the noun 'tabemono'.

夜更かしは体に悪い。

Staying up late is bad for you.

Casual sentence ending without 'desu'.

体に悪いから、食べないで。

It's bad for you, so don't eat it.

Using 'kara' to show reason/cause.

お酒は体に悪いですか。

Is alcohol bad for the body?

Polite question form.

体に悪い習慣です。

It is a bad habit for the body.

Modifying the noun 'shuukan' (habit).

甘いものばかり食べるのは体に悪いです。

Eating nothing but sweets is bad for your body.

Using 'no wa' to nominalize the verb phrase 'taberu'.

体に悪いと分かっていますが、やめられません。

I know it's bad for me, but I can't stop.

Using 'to wakatteimasu' (know that...).

昨日は体に悪いものばかり食べました。

Yesterday, I ate only things that are bad for my body.

Past tense of the main verb while 'warui' stays in present to describe 'mono'.

体に悪いから、野菜も食べてください。

It's bad for you (to not eat them), so please eat vegetables too.

Implicit subject in the 'kara' clause.

体に悪いお菓子は買わないようにしています。

I try not to buy sweets that are bad for the body.

Using 'you ni shiteimasu' to show effort/habit.

寝ないのは体に悪かったですね。

Not sleeping was bad for your body, wasn't it?

Past tense 'warukatta' + 'ne' for agreement.

体に悪い生活を直したいです。

I want to fix my unhealthy lifestyle.

Using 'naoshitai' (want to fix).

体に悪い影響があります。

There is a bad influence/effect on the body.

Using 'eikyou' (influence/effect).

ストレスが溜まるのは、体に悪いだけでなく心にも悪いです。

Accumulating stress is not only bad for the body but also for the mind.

Using 'dake de naku' (not only... but also).

体に悪いと知りつつ、深夜にラーメンを食べてしまった。

Knowing it was bad for me, I ended up eating ramen late at night.

Using 'shiri tsutsu' (while knowing) to show contradiction.

最近の若者は体に悪いものばかり好む傾向がある。

Young people these days tend to prefer only things that are bad for their health.

Using 'keikou ga aru' (there is a tendency).

体に悪い習慣を断ち切るのは、想像以上に難しい。

Breaking unhealthy habits is harder than you'd imagine.

Using 'tachikiru' (to cut off/break) and 'ijou ni' (more than).

保存料がたくさん入っている食品は体に悪いと言われている。

Foods containing many preservatives are said to be bad for the body.

Passive form 'iwarete iru' (is said to be).

体に悪い影響を及ぼす可能性があるため、使用を禁止します。

Usage is prohibited because there is a possibility of negative effects on the body.

Using 'oyobosu' (to exert/cause) and 'kanousei' (possibility).

体に悪いと思ったら、すぐにやめるべきだ。

If you think it's bad for your body, you should stop immediately.

Using 'beki da' (should/must).

不規則な生活は体に悪いので、早寝早起きを心がけましょう。

An irregular lifestyle is bad for the body, so let's try to sleep early and wake up early.

Using 'kokoro gakemashou' (let's keep in mind/try to).

過度なダイエットは体に悪い影響を与える恐れがあります。

Excessive dieting may pose a risk of negative effects on the body.

Using 'osore ga aru' (there is a fear/risk that).

添加物だらけの食事は、長期的に見て体に悪いのは明白だ。

It is obvious that a diet full of additives is bad for the body in the long run.

Using 'darake' (full of) and 'meihaku da' (is obvious).

体に悪いと分かっていても、付き合いで飲まざるを得ない時もある。

Even if you know it's bad for you, there are times when you have no choice but to drink for social reasons.

Using 'zaru o enai' (have no choice but to).

環境汚染が体に悪い影響を及ぼしていることは否定できない。

It cannot be denied that environmental pollution is having a negative effect on our bodies.

Using 'hitei dekinai' (cannot deny).

体に悪いものを排除するだけでなく、良いものを取り入れる姿勢が大切だ。

It's important not only to eliminate things that are bad for the body but also to have the attitude of incorporating good things.

Using 'haiju suru' (to exclude/eliminate).

その健康法は、やり方を間違えると逆に体に悪い結果を招く。

That health method, if done incorrectly, will conversely lead to bad results for the body.

Using 'gyaku ni' (conversely) and 'maneku' (to invite/lead to).

体に悪いと知りながら続けるのは、自己管理ができていない証拠だ。

Continuing while knowing it's bad for you is proof of a lack of self-management.

Using 'nagara' (while) and 'shouko da' (is proof).

体に悪いとされる成分を特定するため、詳細な調査が行われた。

A detailed investigation was conducted to identify components considered bad for the body.

Using 'to sareru' (considered to be).

現代社会における過度な情報摂取は、精神のみならず肉体的にも体に悪い影響を及ぼしかねない。

The excessive intake of information in modern society could potentially have a negative effect on the body, not just mentally but physically.

Using 'kanenai' (could potentially/might - usually for negative outcomes).

体に悪いと一概に決めつけるのではなく、その成分の摂取量に注目すべきである。

Instead of categorically deciding something is bad for the body, one should focus on the intake amount of its components.

Using 'ichigai ni... nai' (not necessarily/not categorically).

労働環境の悪化が、従業員の体に悪い影響を与えている事実は重く受け止められるべきだ。

The fact that deteriorating working environments are having a bad effect on employees' bodies should be taken seriously.

Using 'omoku uketomerareru' (to be taken seriously).

体に悪いというレッテルを貼られた食品が、実は健康に寄与する場合もある。

There are cases where foods labeled as bad for the body actually contribute to health.

Using 'retteru o harareta' (labeled/stigmatized).

体に悪いと分かっていても快楽を優先してしまう人間の心理は、非常に興味深い。

The human psychology of prioritizing pleasure even when knowing it's bad for the body is extremely interesting.

Using 'kyoumibukai' (extremely interesting).

大気汚染物質が微量であっても、蓄積されれば体に悪いのは自明の理である。

Even if atmospheric pollutants are trace amounts, it is a self-evident truth that they are bad for the body if accumulated.

Using 'jimei no ri' (self-evident truth).

体に悪いものを排除しようとするあまり、過度な清潔志向に走るのもまた問題だ。

Going too far in trying to eliminate things bad for the body and ending up with an excessive obsession with cleanliness is also a problem.

Using 'amari' (so much that...).

体に悪い影響を最小限に抑えるためのガイドラインが策定された。

Guidelines were formulated to minimize negative effects on the body.

Using 'saikutei sareta' (formulated/established).

飽食の時代において、「体に悪い」という概念そのものが贅沢な悩みとなりつつある。

In an era of gluttony, the very concept of something being 'bad for the body' is becoming a luxury problem.

Using 'tsutsu aru' (in the process of becoming).

体に悪いとされる嗜好品を文化的な文脈から切り離して論じることは不可能に近い。

It is nearly impossible to discuss luxury items considered bad for the body while separating them from their cultural context.

Using 'fukanou ni chikai' (near impossible).

体に悪い外部刺激に対する生体のレジリエンスこそが、真の健康の指標と言えるのではないか。

Could it be that the biological resilience against external stimuli that are bad for the body is the true indicator of health?

Using 'koso ga' (precisely/indeed).

科学的根拠に基づかず「体に悪い」と吹聴することは、風評被害を招く危険性を孕んでいる。

Publicizing that something is 'bad for the body' without scientific evidence carries the risk of causing reputational damage.

Using 'harande iru' (to be pregnant with/carry a risk).

体に悪いという主観的な感覚が、プラセボ効果の逆、ノセボ効果として作用することもある。

The subjective feeling that something is bad for the body can sometimes act as the nocebo effect, the opposite of the placebo effect.

Using 'sayou suru' (to act/operate).

都市生活の利便性を享受する代償として、体に悪い環境を甘受せざるを得ないのが現代人の宿命だ。

It is the fate of modern people to have no choice but to accept an environment that is bad for the body as the price for enjoying the convenience of city life.

Using 'daishou to shite' (as a price/compensation).

体に悪いという言説が、時として特定の社会集団を排除する装置として機能してきた歴史がある。

There is a history where the discourse of something being 'bad for the body' has sometimes functioned as a device to exclude specific social groups.

Using 'kinou shite kita' (has functioned).

体に悪いものを愛でるというデカダンスな感性は、文学や芸術において重要な役割を果たしてきた。

The decadent sensibility of cherishing things that are bad for the body has played an important role in literature and art.

Using 'mederu' (to cherish/appreciate).

Common Collocations

体に悪い習慣

体に悪い食べ物

体に悪い影響

体に悪いと分かっている

体に悪いもの

体に悪い生活

体に悪い油

体に悪い物質

体に悪い遊び

体に悪い姿勢

Common Phrases

体に悪いですよ

— A polite warning to someone. It implies concern for their health.

そんなに働いたら、体に悪いですよ。

体に悪いからやめなさい

— A command often used by parents to tell children to stop an unhealthy action.

体に悪いから、そのお菓子はやめなさい。

体に悪いものほど美味しい

— A common saying expressing the irony that unhealthy food often tastes best.

体に悪いものほど美味しいのはなぜだろう。

体に悪い気がする

— Used to express a vague feeling that something is unhealthy.

この空気、なんとなく体に悪い気がする。

体に悪いことはしない

— A personal rule or resolution to avoid unhealthy things.

私は体に悪いことはしないようにしている。

体に悪いと知って

— Doing something despite knowing it is unhealthy.

体に悪いと知って、タバコを吸う。

体に悪い影響が出る

— When negative health effects start to manifest.

不規則な生活のせいで、体に悪い影響が出た。

体に悪い食べ合わせ

— Refers to food combinations that are traditionally thought to be bad for health.

天ぷらとスイカは体に悪い食べ合わせだと言われる。

体に悪い仕事

— A job that is physically or mentally taxing to the point of causing health issues.

体に悪い仕事は長く続けられない。

体に悪い環境

— An environment (like a smoky room or a stressful office) that harms health.

体に悪い環境から抜け出したい。

Often Confused With

体に悪い vs 体が悪い

Means 'to have poor health' or 'to have a disability.' Use '体に悪い' for 'unhealthy habits/food.'

体に悪い vs 体調が悪い

Means 'to feel sick right now' (like a cold or fatigue). '体に悪い' is about long-term health impact.

体に悪い vs 気分が悪い

Means 'to feel nauseous' or 'to be in a bad mood.' Not related to the healthiness of an object.

Idioms & Expressions

"百薬の長も飲みすぎれば体に悪い"

— Even the best medicine (alcohol) is bad for the body if over-consumed.

酒は百薬の長だが、飲みすぎれば体に悪い。

Literary

"体に毒"

— Extremely unhealthy, likened to poison. Often used for delicious junk food.

夜中のケーキは体に毒だ。

Informal

"命を削る"

— To 'shave away at one's life.' Used for extremely unhealthy overwork or habits.

そんな働き方は命を削るようで体に悪い。

Dramatic

"腹を壊す"

— Literally 'to break the stomach,' meaning to get an upset stomach from bad food.

体に悪いものを食べて腹を壊した。

Common

"毒を食らわば皿まで"

— If you're going to eat poison, you might as well eat the plate. Used when committing to a 'bad' thing.

体に悪いと分かっているが、毒を食らわば皿までだ。

Idiomatic

"身を滅ぼす"

— To ruin oneself/one's body. Used for severe addictions.

酒は体に悪いだけでなく身を滅ぼす。

Serious

"体に障る"

— To interfere with health. Often used for someone already weak.

無理をすると体に障りますよ。

Polite

"病は気から"

— Sickness comes from the mind. Implies stress is bad for the body.

悩みすぎるのは体に悪い。病は気からと言うしね。

Proverb

"不養生の極み"

— The height of neglecting one's health.

毎日カップ麺とは、不養生の極みで体に悪い。

Formal

"骨身にこたえる"

— To penetrate to the bones. Used for extreme cold or labor that is bad for the body.

この寒さは体に悪いし、骨身にこたえる。

Descriptive

Easily Confused

体に悪い vs 不健康

Both mean unhealthy.

'不健康' is a noun/adjective describing a state. '体に悪い' is an adjectival phrase describing an effect.

彼は不健康な生活をしている vs この食事は体に悪い。

体に悪い vs 有害

Both imply harm.

'有害' is stronger and often refers to legal or scientific toxins. '体に悪い' is for everyday unhealthy things.

有害なガス vs 体に悪いお菓子。

体に悪い vs 危ない

Both mean 'bad/dangerous'.

'危ない' is for immediate physical danger (falling). '体に悪い' is for internal health damage.

その道は危ない vs その食べ物は体に悪い。

体に悪い vs まずい

Both are 'bad'.

'まずい' usually means 'bad tasting' or 'troublesome.' '体に悪い' means 'bad for health.'

この薬はまずいけど、体に悪くない。

体に悪い vs 障る

Both mean negative health impact.

'障る' is usually for things that aggravate an existing condition or interfere with rest.

仕事のしすぎは体に障る。

Sentence Patterns

[Noun] は体に悪いです。

お菓子は体に悪いです。

[Verb-Plain] のは体に悪いです。

寝ないのは体に悪いです。

体に悪い [Noun] は [Verb]。

体に悪い食べ物は食べません。

体に悪いと分かっているが、[Phrase]。

体に悪いと分かっているが、やめられない。

体に悪い影響を及ぼす [Noun]。

体に悪い影響を及ぼす添加物。

体に悪いとされる [Noun]。

体に悪いとされる生活習慣。

体に悪いだけでなく、[Phrase]。

体に悪いだけでなく、精神的にも辛い。

体に悪いという言説が [Verb]。

体に悪いという言説が広まっている。

Word Family

Nouns

体 (Karada - Body)

健康 (Kenko - Health)

不健康 (Hukenkou - Unhealthiness)

悪 (Aku - Evil/Badness)

Verbs

悪くする (Waruku suru - To make bad/worsen)

悪くなる (Waruku naru - To become bad/worsen)

害する (Gaisuru - To harm)

Adjectives

悪い (Warui - Bad)

悪くない (Warukunai - Not bad)

不健康な (Hukenkou na - Unhealthy)

不摂生 (Husessei - Neglect of health)

生活習慣病 (Seikatsu shuukan byou - Lifestyle diseases)

ジャンクフード (Junk food)

添加物 (Tenkabutsu - Additives)

ストレス (Stress)

How to Use It

frequency

Extremely high in daily conversation and media.

Common Mistakes

体に悪いだ → 体に悪い / 体に悪いです
Learners often treat i-adjectives like na-adjectives or nouns by adding 'da'. I-adjectives never take 'da'.
体が悪い (when meaning unhealthy food) → 体に悪い
Using 'ga' makes the body the subject that *is* bad, rather than the target of something bad.
体に悪いな習慣 → 体に悪い習慣
You don't need 'na' to connect an i-adjective to a noun.
体に悪いでした → 体に悪かったです
The past tense of an i-adjective is 'katta', not 'deshita'.
体に悪くありません (too formal) → 体に悪くないです
While grammatically correct, 'akukunai desu' is much more natural for 'not bad' in speech.

Tips

Adjective Conjugation

Remember that '悪い' is an i-adjective. To say 'was bad,' use '悪かった'. To say 'is not bad,' use '悪くない'. This is basic but essential for clarity.

Pair with Habits

Learn this phrase along with '習慣' (shuukan - habit). Saying '体に悪い習慣' is a very common way to discuss self-improvement.

The 'Omoiyari' Nuance

When you say this to a friend, you are showing that you care about their future. It's often followed by '...dakara, ki o tsukete ne' (so, take care).

Guilty Pleasures

Use '体に悪いものほど美味しい' when eating fast food with friends. It’s a great way to bond over shared indulgences.

Don't drop the 'Ni'

If you say '体が悪い', you are telling people you have a medical condition. Always include 'に' to mean 'bad FOR the body.'

Emphasis

Add 'すごく' (sugoku) or 'めちゃくちゃ' (mechakucha) before '体に悪い' to sound more natural and expressive in casual talk.

Context Clues

In Japanese TV shows, look for the text overlay (telop). '体に悪い' is often written in big, scary-looking fonts for effect.

Noun Modification

Practice using the phrase as a modifier: '体に悪い習慣を断ち切る' (Cut off unhealthy habits). It makes your Japanese sound more advanced.

Body + Bad

Just visualize 'Body' (体) + 'Bad' (悪い). The 'ni' is the bridge connecting the bad thing to your body.

Opposites

Always study '体に悪い' and '体に良い' together. They are two sides of the same coin in Japanese health talk.

Memorize It

Mnemonic

Think of a 'CAR' (Ka) with a 'RAD' (Ra) 'DA' (Da) - a body. If you put 'WAR' (Wa) in it, it's 'RU' (Ru) 'I' (I) - bad! Karada ni warui!

Visual Association

Imagine a person's body (体) with a big red 'X' (悪い) over it, specifically pointing to the stomach or heart.

Word Web

体悪い健康タバコお酒夜更かしストレス病気

Challenge

Try to find three things in your kitchen today and label them either '体に良い' or '体に悪い' in Japanese.

Word Origin

The phrase is a combination of the noun '体' (body), the dative particle 'に' (for/to), and the adjective '悪い' (bad). '体' comes from Old Japanese 'karada,' originally referring to the physical frame. '悪い' comes from 'waru-,' a root meaning inferior or undesirable.

Original meaning: Literally 'bad towards the body.'

Japonic

Cultural Context

Be careful when telling someone their habits are '体に悪い' as it can be seen as intrusive if you are not close friends or family.

In English, we often say 'That's bad for you.' In Japanese, specifying 'the body' (体に) makes it feel more literal and physical.

Kenko Bangumi (Health Variety Shows) - TV shows entirely dedicated to what is '体に悪い'. Ishoku Dogen - The proverb that food is medicine. Radio Taiso - The morning exercises done to avoid things that are '体に悪い'.

Practice in Real Life

Real-World Contexts

At a restaurant

体に悪いものは入っていますか？
体に悪いと分かっていても注文しちゃう。
この揚げ物、体に悪そう。
体に悪い油は使っていません。

At work

残業ばかりで体に悪い。
座りっぱなしは体に悪いですよ。
体に悪いから少し休みましょう。
ストレスは本当に体に悪い。

Parenting

体に悪いから食べちゃダメ。
好き嫌いするのは体に悪いよ。
夜更かしは体に悪いから寝なさい。
体に悪いお菓子は捨てますよ。

Doctor's visit

今の生活は体に悪いですか？
体に悪い習慣を教えてください。
タバコは著しく体に悪いです。
体に悪い影響が出ています。

Watching TV

体に悪い食べ物ランキング。
これは体に悪いと言われています。
体に悪い成分を解説します。
体に悪い生活を改善しましょう。

Conversation Starters

"「体に悪い」と分かっていても、やめられないことってありますか？ (Is there something you can't stop doing even though you know it's bad for you?)"

"最近、体に悪いなと感じる習慣はありますか？ (Are there any habits lately that you feel are bad for your body?)"

"あなたの国で、一番「体に悪い」と思われている食べ物は何ですか？ (In your country, what is considered the most 'unhealthy' food?)"

"「体に悪い」ものほど美味しいというのは、本当だと思いますか？ (Do you think it's true that the unhealthier things are, the better they taste?)"

"子供の頃、親に「体に悪い」と言われて禁止されたものはありますか？ (Was there anything your parents banned you from, saying it was 'bad for your health'?)"

Journal Prompts

今日は体に悪いものを食べてしまいましたか？その時の気持ちを書いてください。 (Did you eat anything unhealthy today? Write about how you felt.)

自分が持っている「体に悪い習慣」を一つ選び、どうすれば直せるか考えてみましょう。 (Choose one 'bad habit' you have and think about how you can fix it.)

現代社会で「体に悪い」と感じることをリストアップしてみてください。 (List things in modern society that you feel are 'bad for the body'.)

「体に悪い」食べ物をあえて食べる時の楽しさについて書いてください。 (Write about the joy of intentionally eating something 'bad for you.')

健康のために、体に悪いことを一切しない生活は可能だと思いますか？ (Do you think a life completely free of anything 'unhealthy' is possible?)

Frequently Asked Questions

10 questions

Usually, no. If you say a person is '体に悪い', it sounds like being near them makes you sick. To say a person is unhealthy, use '不健康な人' or '体調が悪そうな人'.

Yes, it is very common for doctors to use this phrase when giving advice to patients because it is clear and direct. However, in medical papers, they use '健康被害'.

They are almost identical. '体に悪い' is slightly more physical/literal, while '健康に悪い' is slightly more abstract. Both are used frequently.

Yes, it is often used for stress or overwork, implying that the mental strain will eventually hurt the physical body.

You say 'これは体に悪くないですよ' (Kore wa karada ni warukunai desu yo).

It is informal and hyperbolic. You can use it with friends when eating something very greasy, but don't use it in a formal setting.

Yes, '体に悪い空気' or '体に悪い水' are perfectly natural expressions for pollution.

The most common opposite is '体に良い' (Karada ni yoi).

No. '悪い' is an i-adjective, so you say '体に悪い食べ物'. Do not add 'na'.

It might be seen as 'osekkai' (meddling). Only use it with people you know or if you are in a position of authority (like a teacher or doctor).