Jesus has been in the wilderness for 40 days, and he has not eaten during that time. 40 days is at the high end of what is considered possible for a long fast. Doctors reckon that most people could live for 4 to 6 weeks, but some have gone further and suffered permanent health problems as a result.
Jesus would have had to start out in a good state of health, and found an adequate water supply. The Bible simple says that at the end of this time he was hungry.
When I was in hospital earlier this year I was nil-by-mouth for about two days. When I recovering from the anaesthetic all I wanted to do was eat. Eventually a nurse made me some toast. At that time it was the best thing anyone could have done for me.
That was just two days, so after forty days Jesus, who was actually starving, would have wanted food more than anything. Food was his greatest physical need – it was a genuine need, much longer without and he will die.
How easy it would be to simply perform a miracle. Make some toast! He knew he had the power, but the question is asked “If you are the son of God .. ” You can prove who you are to yourself, and to me, by just alleviating your hunger. Where would it end? Having done one little miracle he could …
But, even in his state of imminent death due to starvation Jesus knows there's more to life than physical existence, he knows he has to pass these tests, he knows he has to overcome these temptations. “Man does not live by bread alone but by every word that comes from the mouth of God” He recalled the verse from Deuteronomy 8:3, where the Israelites in the desert are fed on Manna.