If looking for nutrition of products should i look at the calories fat or carbohydrates?

All of these: For a healthful diet you need to limit calories and saturated fats. Carbohydrates do contribute to calories and excess of any one type of food is not good. Eat a diet rich in fresh vegetables, fruits, whole grains, nuts; low in saturated fats; no tobacco and no more than one drink a day. Exercise at least 30 minutes each day.

<30% Cal from Fat: Look at the "percent calories from fat". If it is more than 30%, the product is a high fat food and should be avoided. For example, 2% fat milk gets more than 30% of its calories from fat and is not a low fat food, although it is often labeled as "reduced fat". But skim and 1% fat dairy products are truly low fat, with less than 30% of their calories from fat.

All: all are important 20-30% of your total calories should be fat and not higher- so try to choose foods that are not higher in fat. Try to food foods that don't have more than 10 grams of simple sugars per serving...to much sugar is not a good dietary practice. I suggest less looking at boxes and processed foods and more fresh fruits and vegetables- don't need to read a label on an orange

Entire label.: The whole nutrition facts label needs to be read. Focus on fiber, monounsaturated and polyunsaturated fats and protein as indicators of a good choice. Limit simple sugars, saturated and trans fats.