Which is better trans fats or cis fats?

Trans fats are hydrogenated unsaturated fats and they are supposed to be the worst fats there are for your health. Unsaturated fats are healthy fats and saturated fats and trans fats are unhealthy fats. Trans fats are often added to processed foods to extend the shelf life.

There are no such fats as cis fats. There are certainly cis fatty acids and trans fatty acids and the difference between the two is in the hydrogen atoms positions and one could be regarded as an isomer of the other.

All fats are basically triglycerides which means glycerol triesterified with 3 fatty acids.