Have you ever grown potatoes? My neighbor grows them and every year I would go over and help plant and harvest them. One day as we were starting to harvest them I noticed that some of the plants were bigger than others. I gazed with pride at the big huge plants and looked disappointedly at the small ones. I was sure that the bigger plants would naturally have bigger and better potatoes.
When we started to pull them up, I noticed that the bigger plants had smaller potatoes. I wondered about this for a while and then figured it out. Those impressive, huge plants had spent all their time making leaves but hardly any time making potatoes. On the other hand the smaller plants had made just enough leaves to take energy from the sun and then had spent the rest of the time making potatoes.
I think that this is a clear message from God saying "Do not neglect the care of your body but don't worry so much about the outside, it's the inside that counts." The smaller plants still made some leaves. If they hadn't made any leaves they couldn't have soaked up the sunshine and wouldn't have had the energy to make any potatoes at all. This is also a lesson. Don't forget to take care of your bodies or you might miss out on some Sonshine. A potato plant without leaves is useless because it has no energy. So is a Christian without a relationship with Christ, and how can we hear Christ if we are sleepy, sluggish or otherwise unhealthy?