We've gone over exercise with a previous running assignment (hopefully you've taken up some sort of aerobic activity on a regular basis), but the obverse side of the fitness coin is diet.
Rather than try to influence the variety of things you could eat we'll focus on something more immediately controllable and measurable. Women take smaller bites than men (and so should sissies!). This leads to eating slower, which leads to recognizing that you're full before you overeat.
Actual food content is important too, but in this simple assignment you will do a simple task: eat daintily like a lady for a whole day. Only fill the tip of your fork and spoon with food - not the whole thing. Never have a mouthful of anything. Sips and nibbles for the whole day!
Have the complete and utter comportment of a lady when you eat. No elbows on the table, no chewing with your mouth open and all the other perfect manners you would expect from a well-behaved lady.
And since there just aren't many pictures of sissies eating, I'll leave you ladies with this picture of the figure you could work towards, instead: