The total of all energy in an object is its internal energy.
Heat is not the energy the body contains but the energy transferred from one body to another.
We can make clear distinctions between temperature, heat, and internal energy.
Temperature is a measure of the average kinetic energy of the individual molecules.
Internal energy is the total energy of all of the molecules in the object.
Heat refers to the transfer of energy from one object to another due to a difference in temperature.
The heat required to change the temperature of a material is proportional to the mass of the material and the temperature change. (Commonly seen as Q = m*c*deltaT)