In proportion its not, but over doing it is. I am not overweight, I am 5"9 and weigh 11st 13 but still want to eat better than I am just now.
It is not as simple as stating overdoing fats is bad for you, without quantifying what fats, we need to get out of the habit of thinking about fats negatively.
There are numerous types of fat. Your body even makes its own fat from taking in excess calories. Fat is essential to your health because it supports a number of your body's functions. Some vitamins, for instance, must have fat to dissolve and nourish your body.
Monounsaturated fat for example improves blood cholesterol levels, which can decrease your risk of heart disease and benefits insulin levels and blood sugar control, which can be especially helpful if you have type 2 diabetes. Omega3 is also a fat and is highly recommended as part of a healthy diet.
There are two main types of potentially harmful dietary fat which are Saturated fat and Trans fat it is these which are bad for you.
Most fats that have a high percentage of saturated fat or trans fat are solid at room temperature while monounsaturated and polyunsaturated fats are liquid at room temperature.