No! There are different types of fat some of which are good and others that are bad for you. If you are talking about weight gain, the main culprit is carbohydrates.
Anything that you eat that has a liver will have cholesterol and again there is the good and bad. Fat in our body is necessary for adequate hormone function, however and excess can be harmful to the body. But also, one can be “fat” but also fit. That is have a healthy heart. You can outrun a bad diet.