can someone tell me about healthy vs unhealthy fats?

I was wondering if someone could help me find sources of healthy fat...first off I am a vegetarian, and I eat about 1200-1400 calories a day, without exercise.  What foods can provide me with "good" fat without upping my calories too much?

Thanks :)

All fats are about 100 calories a tablespoon, whether good or bad.  Olive oil is about the best. However all-natural peanut butter is also great, almost as good as olive oil, but you get some protein, and it is food for the Gods.

thank you, shiptona...how would I incorporate olive oil in to my diet?  Just with cooking, or maybe salad dressing?

Olive oil is awsome for cooking, I pretty much don't use any other types of oil to pan cook anything any more.  A couple tablespoons in the fry pan when I cook sliced veg, or in the water when I boil/blanche string beans and the like, it's yummy and I've found I don't need any butter anymore.  There are different grades of olive oil, I use the medium one mostly, but my mother uses the dark in a lovely garlic balsamic vineger salad dressing, a couple of tablespoons of that dressing on a really fresh salad and all my comments about salad being rabbit food goes out the window!

When it comes to fat though, the most important thing is to avoid trans fats. All those stick margarines, even the light ones? Full of trans fats. Their chemical makeup is worse for our bodies then other normal fats, and they're mostly found in highly processed foods anyway.

Edited for typo

Fats are a necessity to every diet. Fats helps nutrient absorption, nerve transmission, maintaining cell membrane integrity etc. But, when consumed in excess amount, fats contribute to weight gain, heart disease and certain types of cancer. Some fats promote our health positively while some increase our risks of heart disease.

bad fats: saturated and trans fats

good fats: monounsaturated and polyunsaturated (omega 3's included in this group)- both help lower cholesterol

You can get good fats by eating grilled salmon, nat'l peanut butter, nuts , avacodos, canola oil, olive oil, flaxseed oil, other fishes and yes you can use olive oil for both cooking and dressings (and of course take it easy on the portions)

very helpful, thank you!!