Have you ever wondered if you should remove the lower leaves of your tomato plants? Once someone showed me a picture with hardly any leaves on his tomato plants, wasn’t a pretty sight, it was like a sheep after shearing, and then he wondered why the fruits did not grow bigger. It is just like everything else in life, do it with moderation!
It is wrong to think that exposing the fruits to direct sunlight will encourage them to ripen faster; it is actually the right temperature which speeds up ripening and not the sunlight. In the greenhouse especially direct sunlight on the fruits can be harmful as it could overheat the fruits and blotchy patches will appear on them. I know it is not really a problem outdoors right now, but indoor tomatoes already bear fruits and I will have to paint my greenhouse too as the sun came out today and got really hot under glass. Also the plants produce their food in the green leaves so if you remove too many you will restrict plant and fruit growth.
If your plants look similar to the above picture you should definitely remove the lower leaves which are touching the soil, also any yellowing leaves too. Normally the lower leaves start to yellow, break them off as the season goes along. Also in the greenhouse in perfect conditions the tomato plants can get very bushy and the leaves get very thick, strip the lower leaves and some of the middle leaves too of these plants as the humid trapped air will encourage fungal diseases. The removal of some of the leaves helps with air circulation around your plants, also the weak yellowing leaves more likely to catch diseases.