Strictly speaking the products of photosynthesis are glucose, water and oxygen. The photosynthetic process takes carbon dioxide and water and uses the photons of light to fix the carbon and create the glucose.
Glucose is the then the "food" that allows other processes to take place. It is broken down by a process called glycolysis and then subsequently broken down further in the Krebs cycle. Both of theses processes create ATP which is the high energy compound that makes everything work. ATP has three phosphates in its structure and these are considered high energy chemical bonds. By splitting off a phosphate energy is release which is then used for other metabolic processes.
Essentially think of ATP as the money driving the economy. You need glucose to generate ATP via glycolysis, krebs cycle, and the electron transport chain. There are some other important things generated as well like NADH, etc but I won't make this more complicated.
The ATP, along with other things like the NADH are then used to create other important compounds via a variety of synthetic processes. These include generation of amino acids, lipids, and other more complex carbohydrates. In addition to metabolically creating these substances, some can be obtained by "food " intake. Proteins, fats, and complex carbohydrates are the actual food. They are then broken down to more simple amino acids, fatty acids, and glucose.
So you can see that intake of food provides energy, but in addition in plant and photosynthetic systems, the glucose can be generated by harnessing the suns energy as photons to fixate the carbon and create glucose.
It all plays together....I used to have chart that filled a wall and had all the metabolic processes laid out (was useful when studying biochemistry)- staring at it would boggle the mind!
Hope this helps and hasn't confused the issue further.
