油脂 and 脂肪: Oils, fats, and the residue on a fan
Compare 油脂 in food labels or greasy residue with 脂肪 in the body or fish. Follow the named target while allowing the meanings to overlap.
Oils and fats named as 油脂
油脂 means oils and fats. 「食品に含まれる油脂の量を表示で確かめた。」 reports checking the label for the amount of oils and fats in food. The amount included in the food is what was checked.
「換気扇に付いた油脂を専用の洗剤で落とす。」 has the English wording “Use a special cleaner to remove the greasy residue from the exhaust fan.” This imperative names residue attached to the fan; here the focus is the residue’s identity.
Fat in the body or food
脂肪 means fat. 「理科の授業で脂肪が体内に蓄えられる仕組みを習った。」 reports learning in science class how fat is stored in the body. Storage in the body is the subject studied.
「この魚は身に適度な脂肪があり、焼くと香ばしい。」 says this fish has a moderate amount of fat in its flesh and becomes fragrant when grilled. The fat belongs to the fish’s flesh.
The name and its target
The food-label 油脂 and the fish’s 脂肪 can both concern fat in food. These examples do not establish an exclusive plant-fat versus animal-fat division.
The fan’s 油脂 is attached greasy residue, while the body’s 脂肪 concerns stored fat. Read the location or containing object to identify the target; the examples do not add dietary recommendations or cleaning procedures.
Does 換気扇に付いた油脂 refer to fat stored in the body or to something attached to the fan?
Show the answer and why
It refers to greasy residue attached to the fan. Its target differs from the body-storage example of 脂肪; the two names are not divided exclusively into plant and animal fats.