A calorie was defined a couple centuries ago as the amount of heat required to raise one gram of water one degree Centigrade. This is a tiny amount so the kcal (1000 calories) is used for food measurement. It's been shortened to calorie so EVERYTHING you read about kcals. is exactly the same as calories. Just forget the scientific definition (except in a Physics lab.)
A kilocaloire IS a Calorie for diet purposes.
(Forget about joules and kjoules if you live in the USA....just another measurement of heat more popular in Europe...for the curious 1 Kcal = 4.187 Kj.)
Food energy could just as readily be listed in kilowatt-hours !
On a 1300 calorie diet, maybe look to keep protein at 65 grams MINIMUM. THat should keep you healthy.
One ounce = 28.35 grams (say 28!)
You're going to need a good diet scale and an excellent nutrition value table like the US Department of Agriculture: http://www.nal.usda.gov/fnic/cgi-bin/nut_search.pl
Type in the food and hit ENTER!