The forbidden fruit was "good for food" in one sense, but very bad in another

Genesis 3:6

"When the woman saw that the fruit of the tree was good for food and pleasing to the eye, and also desirable for gaining wisdom, she took some and ate it. She also gave some to her husband, who was with her, and he ate it."

The first thing that Eve sees when she looks at the fruit of the tree is that it is good for food. Now, she hasn't tasted it yet so she can only guess that the fruit must be good for food based on its outward appearance. When she compares it to the fruit of other trees that she has eaten from, the forbidden fruit looks delicious.

We, however, come to this passage from a different perspective. We have sinned already and we know that the forbidden fruit tastes delicious, because we have bitten into it and have tasted it and we have found it to be so. We know that the fruit of the tree is good for food in the sense that it does gratify our senses, and it is that fact that keeps us coming back for more.

However, though it tastes good, the forbidden fruit is not healthy for us spiritually. In that sense it is not good for food, but the exact opposite. Far from being beneficial to us, the fruit of the tree destroys us and kills us. What God says about it is true: "when you eat of it you will surely die."

The Word of God and Jesus Christ himself, on the other hand, are good for food, always and in every way. When Jesus was tempted by the devil to turn stones into bread, "Jesus answered, 'It is written: "Man does not live on bread alone, but on every word that comes from the mouth of God."'" (Matthew 4:4) Also in John 6:54 Jesus says, "Whoever eats my flesh and drinks my blood has eternal life, and I will raise him up at the last day."