Dear student,

Eating oily food sometimes generally didn't cause any bad effect on healthy human body. But if you are eating oily food regularly then it can cause some bad effects on your health and on your body.

Some of these bad effects of eating oily foods regularly are :-

May impair brain function - for a student eating regularly oily food is not good for his/her brain

May cause acne - one of the most common effect of eating regularly the oily food in teenagers

May raise your risk of diabetes - there is also a high risk of diabetes and therefore the diabetic persons are advised not to take any type of oily food

May increase your risk of heart disease and stroke - this is one of the most dangerous side effect that can happen generally for old person taking oily food regularly is not advised as it can cause heart attack.

May lead to weight gain and obesity - if you want to look smart advantage keep your body fit then you must avoid eating oily food because this can lead to gain weight

Also there are more bad effects like stomach pain , or impairment of gut bacterias , etc.
So it is advisable that you should not eat oily foods regularly.