Topamax questions here, so bear with me.
How long have you been on Topamax?
How "fast" (mg per week) did they increase your dose? (that can cause problems if increased too fast.)
Have they preformed blood work to check your levels on Keppra and Topamax?
Topamax can take ROUGHLY one week per 25mg tab to level out in your system. So they like to go slow when introducing it. They can go as fast as 50mg/wk if they think the person can handle it.
When doing LARGE increases (100mg) it is dangerous, but SOME patients can handle it (I could) when they increase the dose from (EXAMPLE 100mg to 200mg).
Topamax most likely is the CAUSE of your eating issues . You need to learn to FORCE yourself to eat. I found that aroma's triggered my desire to eat. Topamax also changes the taste of some foods (compared to pre medication). So best advice is try "snack sized" servings during the day and one REAL MEAL at night.
Even though the medication makes you think you are not hungry, EAT. You need the nutrition. It took me going two days (without food) when I had to develop a way to eat when on the medication. You just have to force the meal down.
As for the emotional questions... Keppra is known to cause "uncontrollable emotional outbursts" in a small group of patients.
Hope that helps you a bit.