@blackholeeyes calorie intake is ofc important. But more importantly,the type of substance that you consume is also important.
Example
Menu 1 : hotdog and fries.lets say 1kcal
Menu 2 : veg soup.grilled chix breast w/o skin.rice.omellete. about the same kcal. 1kcal.
Menu 2 would be better because of the reduced oil.even though they have the same amount of cal.
And never use the 'particular food' diet like keto etc. The human body is designed to process all foods. If u use that diet, you'll rebound easily once you eat carbs.
And rather than 2 or 3 full meal a day, it's better if you have 3 moderate meals and healthy snacks inbetween. This is to take care of your blood sugar level. I won't bore you with the specifics of why. Just know that this will help.
Moderate exercise will also help. A LOT.