To me it seems like overweight people are always eating fried foods.
I have this image that obese people only eat fried foods.
I get the impression that obese people only eat fried foods.
「太ってる人 」は直訳しますと "fat people" になるのですが、失礼に聞こえますので、科学的な "overweight"や"obese"(極端な場合)を使った方が良いです。
(私にとって)〜イメージがあります = "To me it seems like 〜 " / "I have the/this image that 〜 " / "I have/get the impression that 〜 "
ご参考になれば幸いです。