Here’s how the toning equation goes:

No workout + Diet = less muscle and less fat = same perceived level of ‘toning’ just with small size.

Workout + No Diet = more muscle and the same amount of fat = same perceived level of ‘toning’ but now with bigger arms that you hate and blame your trainer for making you look ‘bulky’.

Workout + Diet = EQUAL muscle and less body fat (since you’ll be losing muscle as you lose fat but then gaining it back as you work out for a zero sum loss)