Q:

What is the difference between cal and Kcal?

When I started working out, I came across these two terms that are used interchangeably.
On edible products energy is written in terms of Kcal
While when running on a treadmill we lose calories.
What is the difference between them? And which one is the real deal?

A:

Answer: 1 Kilocalorie equals 1 Calorie. Note the capital "C". 1 kilocalorie equals 1000 calories. Note the lowercase "c". So Calories and kilocalories are pretty much the same thing.
Kilocalories

It's easy to get confused about calories and kilocalories since, in a
  nutrition context, values are actually given for the number of
  kilocalories in a food, but referred to simply as calories.

1000 calories= 1 Kcal
Nutrition.gov

The "calorie" we refer to in food is actually kilocalorie. One (1)
  kilocalorie is the same as one (1) Calorie (upper case C).

Rapidtables.com

1 Cal = 1 kcal
1 small calorie (cal) is equal to - 1/1000 small kilocalorie (kcal):
1 cal = 0.001 kcal

May help you understand the relationship between them. 

A:

Generally speaking, 1 kilocalorie = 1000 calories (definition here).
But the confusing part is explained here:

The energy used in physical activity and the energy stored in foods is actually given in kilocalories (the heat energy required to raise the temperature of one kilogram of water by one degree Celsius). Often kilocalories are referred to as kcals or as large calories or as Calories, where the capital ‘C’ indicates kilocalories. However, because a calorie is such a small unit of energy the word ‘calorie’ to define a small calorie is mainly used in scientific literature. Most of the time ‘calorie’ spelled with the small ‘c’ actually refers to the kilocalories provided in food and used during exercise. (you can read about it more here)

So, the answer is, in your case, "calorie" means the same as "Kcal" or "Kilocalorie".

