In this week's parshah we read about the Mann, the bread that fell from the sky, that our ancestors ate for 40 years in the desert. According to the Rambam the greatest of all miracles mentioned in the Torah is the manner in which Hashem provided for us in the desert.
But if you think about it, really all food is a great miracle from Hashem - no less then the Mann. In the words of Rabbi Avigdor Miller:
Hashem causes the food to result from the combined action of water, sunlight, carbon-dioxide, and soil. Carbon-dioxide is but three parts of ten thousand of the air, and the plant would immediately exhaust the surrounding air of its carbon-dioxide if not for the marvel of wind that moves air around and thus ensures a constant supply. The light comes from the sun which is 93 million miles away, but it speeds at 186,000 miles per second to reach the plant to perform the miracle of photosynthesis. Thousands of steps are performed in the production of food, each in precise sequence and according to a precise chemical process. This process is no less miraculously designed and executed than the falling of the Mann.The episode of the Mann and the holiday of Tu B'Shvat are annual reminders of the greatest miracle - the food we eat. But once a year is not nearly enough. That is why we have brachot that we say before we eat. Brachot are not only a way to thank Hashem, they are also a way to draw our attention to the miracle of the food that came from the ground so that we may better appreciate the great kindnesses that Hashem provides for us every second.