I give mine some squash ( like pumpkin) every once in a while.. it cleans them out but they love it so I let em have it when I think theyve been "good".
Ive looked up the sugar content and its far less than most fruits..
Although, I dont see a problem with a strawberry here and there.
They should love, non sprayed, clean, hibiscus flowers. The leaves of hibiscus are also a good food item for them. Dandelion flower, is also a good treat, as are mallow flowers.
Instead of the strawberry itself (it has a high sugar content and can cause parasite blooms) feed the leaves of organic strawberries. Hibiscus flowers are great as mentioned above.
2 of my 5 tortoises love dandelion flowers, the other 3 won't touch them. All LOVE hibiscus flowers, I have 2 different kinds that bloom at different times in my garden. Right now miner's lettuce (google it for pics) is also growing under evergreen trees all over the place, and it is so tender, the torts LOVE it.
I might be a big meanie (my kids don't get sweets either), but I don't give my tortoises fruit at all. It's not good for them, and it's not like they will learn tricks... they know me as the 'food bringer' and will come to me and eat dandelion leaves out of my hand... no sweets necessary, just good consistent care, gentle handling, and lots of patience.