Some parents believe that watching TV programs lead to over-weight in children.
1 پسندیده
lead → leads
over-weight → overweight is correct. It falls into closed compounds, not hyphenated ones.
3 پسندیده
leads
درسته. مورد اول که گفتید درسته. دوم نه کاملا.
1 پسندیده
Not perfectly? 
I’m afraid to say that’s another mistake in your sentence and it should be corrected.
3 پسندیده
دو تا غلط داره. بعد از جرند ( فعل + ing) فعل سوم شخص میباشد. غلط دوم بعد از
lead to
باید اسم بیاید نه صفت.
Overweightness
1 پسندیده
You get it wrong.
Overweight can be a noun, too. If you’re not sure, you can look it up in Collins dictionary.
I was aware it should be noun after leads to. 
2 پسندیده
Yo, OK, you’re right. Collins dic. is kinda shit but I’m not intended to capture image of my medical reference book written by American author, Barbara Janson Cohen where it uses overweight as a noun.
Take it easy, be more flexible.
My preferred dic. is Oxford but I make use of other dictionaries too.
1 پسندیده
My source is long man , I used overweight and examiner corrected.
1 پسندیده