Tomatoes starting to turn red

I noticed that a couple of my tomatoes are finally turning red and rippening. I am actually going to taste one in the next day or two. The leaves on the lower parts of the stem have started to turn brown and die. I think is the natural growth cycle of the plants because there is new growth on the upper stems of the plants. All of the red fruit is on the lower section of the plants and the higher sections have lots of flowers so I hope that once I pick the ripe fruit some of the nutrients will then start to produce fruit on the rest of the plant.