Is it good to eat sweetcorn every day? will it increase body weight?

I think corn: is a fine food: it is rich in anti-oxidants, contains carotenoids which may be good for your eyes, has some fiber so helps with digestive regularity. You could eat it every day as one of your 5+ vegetables. If you don't exceed calories needed to maintain weight, you will not gain weight just because some of them are from corn. Enjoy this yummy vegetable (watch the salt and butter!). Good wishes:)

No and yes: No, that is not considered a good source of calories. Yes, depending on your exercise levels and other nutrition, you might gain weight over time.