You need to start by photosynthesis process that uses the sunlight, water from soil and carbon dioxide from air to help a plant to grow and to reach maturity.
The sunlight's enrgy is stored in plant as starch and sugar and it is crucial in development process of the plant.
Then, the plant is harvested and either you eat it, or it is given to animals to feed them. In the second case, the animals eat the plant and, in this way, the energy stored in the plant is transfered and stored in the fat or muscle tissues of animals.
Then, if you eat the animal's meat, the energy stored in muscle tissues and fat is transfered to your body. Thus, your body becomes energetic.
While your body makes use of the captured energy, you will exhale carbon dioxide during the respiration process. This carbon dioxide will be used by the plant in the process of photosynthesis and in this way the cycle keeps going on and on.
Energy absorbed by the earth is in the form of thermal energy- heat and light anergy. This is absorbed by plants and used to produce food for plants- ohotosynthesis.
Most of the food eaten by man is from plant. This proves that the food we ewat is majorly as a result of the energy from the sun.