One envelope of gelatin will thicken up to 2 cups of liquid. One package of gelatin has 25 calories and not fat.
To use the gelatin you must first soften it in cold water or other liquid for about 5 minutes. You will see the gelatin granules swell during this time. Then the gelatin needs to be gently heated and stirred for it to dissolve. Another method is to dissolve the gelatin in boiling water, this can be a bit trickier. If you get the gelatin too hot it will get stringy and not work.
An easy way to dissolve gelatin is in the microwave. In a glass measuring cup, sprinkle one envelope of unflavored gelatin over 1/2 cup of cold water. Let stand one minute. Heat the water and gelatin on high power for 15 seconds, then stir. Heat an additional 25 seconds on high and stir. Gelatin is fully dissolved when the granules dissolve. Continue stirring until it is completely dissolved, which can take up to 5 minutes.
Gelatin is used as a thickener and stabilizer for molded desserts, thickening juices, aspic, cold soups, marshmallows and candies.